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CLOSE THIS BOOKRoadside Bio-Engineering - Site Handbook (DFID, 1999, 160 p.)
Sector Four - Production of bio-engineering plants
VIEW THE DOCUMENT(introduction...)
VIEW THE DOCUMENT4.1 Nursery establishment
VIEW THE DOCUMENT4.2 Components of a nursery
VIEW THE DOCUMENT4.3 Propagation of grasses
VIEW THE DOCUMENT4.4 Propagation of shrubs and trees
VIEW THE DOCUMENT4.5 Propagation of bamboos
VIEW THE DOCUMENT4.6 Nursery management
VIEW THE DOCUMENT4.7 Seed collection, treatment and storage
VIEW THE DOCUMENT4.8 Assessing the quality of bio-engineering nurseries

Roadside Bio-Engineering - Site Handbook (DFID, 1999, 160 p.)

Sector Four - Production of bio-engineering plants


Figure

This section gives the following information:

· where to establish a nursery (Section 4.1);
· the components, layout and materials of a nursery (Section 4.2);
· propagation of grasses (Section 4.3);
· propagation of shrubs and trees (Section 4.4);
· propagation of bamboos (Section 4.5);
· nursery management (Section 4.6);
· seed collection and storage (Section 4.7);
· assessing the quality of bio-engineering nurseries (Section 4.8)


Figure 4.1: Nursery activity calendar: low-altitude nurseries For nurseries below about 1200 to 1500 metres above sea level


Figure 4.1: Nursery activity calendar (continued): high-altitude nurseries For nurseries above about 1200 to 1500 metres above sea level

4.1 Nursery establishment

What are nurseries for?

A nursery is a factory to supply plants, in this case, for a bio-engineering programme. A good nursery will supply:

· enough plants of the right species,
· in good, healthy condition,
· in the form required for planting;
· at the right time; and,
· at a reasonable cost.

Young plants are delicate organisms and their production is a skilled business. For this reason, nurseries require careful organisation and operation.

When are nurseries used?

Nurseries are a permanent feature. The production of plants is seasonal at lower altitudes (below about 1200 or 1500 metres, depending on the warmth of each individual nursery location) but continues throughout the year above this altitude. The calendars in Figures 4.1 show the variations.

Selecting a suitable site

Before choosing a site, carefully define the objectives of the nursery, including:

· the approximate number of plants of each type (i.e. grass, shrubs/trees and bamboos) to be produced each year;

· the location of the planting sites that the nursery must supply;

· the availability of land belonging to the Department of Roads.

The choice of site is the single largest factor affecting the quality of plants. The nursery must be carefully prepared to receive seeds and cuttings. Therefore, you must choose the site at least six months before the first seed is to be sown.

Nurseries need to be on land owned by the Department of Roads (or leased for at least 10 years) and as close as possible to the sites they will serve. At the same time, however, the location must be technically suitable. You will rarely be able to get everything just right, so the final selection should be based on evaluating the relative advantages and disadvantages of three or more possible sites after you have thoroughly inspected them

The following are the main technical factors that must be satisfied when establishing a nursery.

Water supply

A reliable, adequate water supply is essential for all nurseries. A guaranteed supply is required at the following rates:

· 150 litres (0.15 cu. m) of water per day for every 10 sq. m of grass beds;
· 500 litres (0.5 cu. m) of water per day for every 10,000 polypot seedlings;

if watering is done with a watering can, and rather more for watering with hose pipes. Whatever the source of the water, check that it is available throughout the year; especially check the flow in the driest months: March, April and May (Chaitra to Jestha).

Figure 4.2: Calculating the nursery size

NURSERY COMPONENT

CALCULATION BASIS

AREA ALLOWED

Office/Store/Chowkidar's hut

Estimate

Normally allow 15 sq. m

Vehicle access and turning area

Estimate

Normally allow 50 to 100 sq. m

Pathways to all parts of the nursery

Estimate

Normally allow 50 to 100 sq. m

Working area

Estimate

Normally allow 25 sq. m

Soil and sand stores

Estimate

Normally allow 20 sq. m

Compost bays

Standard size

Normally allow 10 sq. m

Water tank and accessories

Standard size

Normally allow 10 sq. m

Drainage systems

Estimate

Normally allow 25 to 50 sq. m

Grass beds: see Figure 4.4

100 cuttings per sq. M

Depends on requirement: see below

Seed beds


Normal requirement Normally allow 5 sq. m

Standout beds for polypot seedlings

128 polypots per sq. m

Number of seedlings required × 1.25 ÷ 128

Beds for hardwood cuttings

40 cuttings per sq. m

Above 1500 m: number required × 2 ÷ 40



Below 1500 m: number required ÷ 40

Bamboo beds

4 cuttings per sq. m

Above 1500 m: number required × 3 ÷ 4



Below 1500 m: number required × 2 ÷ 4

Space between beds

Estimate

Total area of beds × 0.75

Space for terracing on slopes

Estimate

Total area of nursery × 0.5

General location

The site should be near to the road and as close as possible to the centre of the area to which plants will be supplied.

Physical features

Aspect is very important. North-facing slopes are cooler and more humid and are better for nurseries at lower elevations, whereas nurseries above 1200 metres are better on warmer southern slopes.

Drainage is important to avoid waterlogging of the beds. In the Terai, a slope of 2 - 3 percent is best if possible. In the hills, terracing is usually necessary.

Avoid areas threatened by landslides, flooding or strong winds, and at higher elevations avoid sites which are particularly liable to frost (e.g. small valley bottoms).

Availability of materials and labour

You should select a location with the best quality soil available. If possible, it should be an old forest soil, loamy and with a good content of organic matter, and on a well-drained site.

Additional soil will be required for the production of polypot seedlings. This should be a sandy loam forest topsoil; if the available soil is too heavy (i.e. contains too much clay), sand will also be required.

Easy access to stone for building the nursery wall and beds as well as other items, such as a water tank, a shed and a compost bin, is also an advantage. Otherwise stone or bricks have to be brought in.

A lot of labour is required for constructing the nursery and later on for tasks like transplanting grasses, carrying soil and filling pots. You should locate the nursery where it is possible to obtain labour without difficulty at most times of the year.

Calculating the appropriate size

The amount of space required for a nursery depends upon the number of plants to be produced, the time they will spend in the nursery and the density at which they will stand in the beds. The slope and the quality of the site will also influence the decision on how much space to allocate.

Before you start to calculate the area needed, list the various components of the nursery that you require and calculate the area required for each. Figure 4.2 summarises this.

Figure 4.2: Calculating the nursery size (continued): worked examples

NURSERY COMPONENT

TERAI NURSERY**

NURSERY AT 1400 METRES

NURSERY AT 2000 METRES

Fixed elements (Office/Store/ Chowkidar's hut, vehicle access, pathways, working area, soil and sand stores, compost bays, water tank and drainage)

265 sq. m

265 sq. m

265 sq. m

Grass beds

290

633

633

Seed beds

5

5

5

Standout beds for polypot seedlings

98

98

195

Beds for hardwood cuttings

25

25

25

Bamboo beds

50

50

75

Sub-total: beds

468 sq. m

811 sq. m

958 sq. m

Space between beds

351

608

718

Sub-total: all above components

1,084 sq. m

1,684 sq. m

1,941 sq. m

Space for terracing on slopes

0

842

970

Total area required*

1,084 sq. m
or 2.1 ropani
or 0.2 bigha

2,526 sq. m
or 4.8 ropani

2,912 sq. m
or 5.6 ropani

*1 ropani = 0.052 hectare.

**Assume that each nursery is expected to produce, per year 100,000 grass slips, of which 10,000 are amliso; 10,000 polypot shrub and tree seedlings; 1,000 rooted hardwood cuttings; and 100 rooted bamboo culm cuttings.


Figure


Figure 4.3: Typical low-altitude nursery that has been well laid out

The main components of a nursery are as follows:

General:

Compound wall or fence


Office/Chowkidar's hut


Vehicle access and turning area


Pathways to all parts of the nursery


Working area

Storage:

Nursery store


Soil and sand stores


Compost bays

Water:

Water tank and accessories


Drainage systems

Beds:

Grass beds


Seed beds


Standout beds for polypot seedlings


Bamboo beds


Shades for beds

Other areas and corners for perennial grass and hardwood stock plants

How to estimate the requirement for grass beds

Grass slips are produced in nursery beds from cuttings made from either a portion of root and stem, or just stem. They are planted in nursery beds at a density of 100 per sq. m.

Bio-engineering nurseries have to produce more grass slips than any other plants. It is therefore important to estimate the quantity of grass slips required, and the nursery space they need, early on. This is done in two stages: determining the number of slips per planting drill, which depends on the type of grass; and then calculating the multiplication factor for the production of the grass.

Number of grass slips per planting drill

The planting drills described in the rate analysis norms, given in the Reference Manual, consist of different numbers of slips, depending on the type of grass, the nature of its rooting and the parts used for vegetative propagation. Rhizomatous grasses1, such as amliso, require only one slip per planting drill. Fibrous rooting grasses, such as babiyo, kans, khar and phurke, require two slips per drill. Grasses grown from single or double-node stem cuttings, such as dhonde, narkat and napier, require only one slip per planting drill.

1 Some grasses, especially bamboos, grow with a form of underground stem called a rhizome. Roots and shoots form from nodes on the rhizome.

Calculation of grass slip multiplication in the nursery

The nursery multiplication of grasses by slips produces a three to seven times increase in the number of plants each time the grass clumps are split out, depending on the species, altitude and time of planting in the nursery. At altitudes below 1200 metres, slips of grasses except amliso can be multiplied by seven times; amliso can usually only be multiplied by three times. At higher altitudes, usually above about 1200 metres, a three-times multiplication is usually only possible in one warm season. However, the timing of planting in the nursery bed also regulates the productivity. Figure 4.4 summarises all this information.

How to estimate the requirement for hardwood cutting beds

Hardwood cuttings can be propagated at the rate of 40 cuttings per square metre of bed. However, in nurseries above 1500 metres, you need to allow two complete bed areas. The reason for this is that above 1500 metres the cuttings often have to remain in the nursery for 16 months or more.

Figure 4.4: Calculation of grass slips numbers

NURSERY ALTITUDE

PROPAGATION METHODS

SPECIES

CUTTINGS PLANTED IN NURSERY

NUMBER TO PLANT

Above 1800 m

Rooted slip cuttings

Amliso

Previous August

Final site number ÷ 3



Any other grasses

Previous August

Final site number × 2 ÷ 3


Stem cuttings

Dhonde, narkat

Previous August

Final site number × 0.25

1200 to 1800 m

Rooted slip cuttings

Amliso

February/March

Final site number ÷ 3



Any other grasses

February/March

Final site number × 2 ÷ 3


Stem cuttings

Dhonde, narkat

February/March

Final site number × 0.25

Terai to 1200 m

Rooted slip cuttings

Amliso

February

Final site number ÷ 3



Any other grasses

February

Final site number × 2 ÷ 7




April/May

Final site number × 2 ÷ 3


Stem cuttings

Dhonde, narkat

March

Final site number × 0.25

Figure 4.5: Main construction features of nursery beds

BED TYPE

GRASS BEDS

SEED BEDS

STAND OUT BEDS

BAMBOO CUTTING BEDS

Purpose

Beds for grass seeds, grass slips, hardwood and stump cuttings of shrubs and trees

Very finely prepared beds for germinating small shrub and tree seeds

Frames in which to stand polypot seedlings

Beds for the propagation of bamboo culm cuttings

Bed size *

1000 mm wide × 250 mm high

1000 mm wide × 170 mm high

1000 mm wide × 150 mm high

1000 mm wide × 300 mm high

Details of construction

50 mm of washed gravel placed above the ground; then 50 mm of 1:1 mix of sieved soil and compost; and topped with 150 mm of 3:1 mix of sieved forest topsoil and washed sand

50 mm of washed gravel placed above the ground; then 50 mm of unsieved forest soil; 50 mm of 1:3 mix of sieved forest soil and washed sand; and topped with 20 mm of washed, sieved and sterilised sand.

50 mm drainage layer of gravel placed above compacted ground. A flat stone or brick surround

Ground below the bed is dug to a depth of 300 mm. Bed is made with 100 mm of unsieved soil (lower) and 200 mm of sieved soil (upper). A bund 100 mm high is formed around the edge

Shade type

No shade; hessian sheet can be laid on the surface if required

Complete top shade of thick thatch and polythene sheet

Removable top shade of rolling bamboo slats, made from split culms

Top shade of thick thatch; side shades of hessian sheet

* Beds may be constructed to any length

How to estimate the requirement for bamboo beds

Bamboo culm cuttings can be propagated at the rate of four cuttings per square metre of bed. However, in nurseries below 1500 metres, you need to allow two complete bed areas, and in nurseries above 1500 metres, three complete bed areas. The reason for this is that below 1500 metres the cuttings remain in the nursery for 16 months and, above 1500 metres, for 28 months.

Layout and construction of the nursery

Nurseries are essentially a form of factory and need to be laid out with the production process in mind. Some aspects are usually pre-set. For example, the point of road access is usually fixed. The office/store/chowkidar's hut is normally placed near this gate. In the hills, the water tank has to be at the highest point of the nursery in order to allow gravity feed by hose pipe; in the Terai it should be located in the centre, as water is needed equally throughout the nursery (see Figure 4.3).

Other considerations are as follows.

· Place the soil and sand store beside the vehicle access and turning area.

· Locate the working area beside the soil and sand store.

· Locate the seed beds close to the chowkidar's hut, since these require more attention.

· If it is a remote area, make the chowkidar's hut big enough for his family as well.

· Ensure easy access to all parts of the nursery. Do not put the beds too close together. Remember that when shades are erected, they will reduce the space between the beds.

· Make sure that the whole nursery is well drained. In particular, check that there is no risk of any of the plant beds being flooded.

· Use any remaining corners and rough areas for long-term production of grass and hardwood cuttings.

All construction must be done to a high standard, as per the norms and specifications. Nurseries are usually permanent fixtures, and therefore must be designed and built to last.

Figure 4.5 summarises the main features of nursery bed construction.

4.2 Components of a nursery

Nursery equipment

Main permanent equipment

The main equipment required is as follows.

Pate kuto

Chuche kuto

Hasiya

Shovel

Kodalo

Kodali

Chuppi

Khukuri

Dante

Axe

Hammer

Doko

Crowbar/khanti

Watering can with roses

Hose pipe

Scissors/secateurs

Tin trunks with

Flit gun sprayer

padlocks

Leather or paper punch

Soil and sand sieves

First aid kit

Tape measure

Plant carrying trays (metal or wood, ideally 400 × 2009 mm, with sides 100 to 200 mm high)

Seed trays (optional; make by cutting oil tins in half).

Tools and equipment must be kept in good working order. Replace defective items before they are needed, and keep blades sharp.

Expendable materials

The main expendable materials required are as follows:

Soil

Sand

Compost

Seeds

Grass slips

Bamboo cuttings

Hardwood cuttings

Fungicide and insecticide

Fertiliser

Polypots: 4" × 7", 200

Heavy gauge


gauge black


polybags for


polythene


storage

polythene sheeting

Shade material

String


(bamboo,

Wire mesh


thatch, hessian)

Soap

Wire

Waterproof marker pens

Nails

Registers: grass slip/

Seedbed labels


hardwood cutting,

Pens/pencils


seedling

Expendable materials need to be re-supplied each year and you should order them well in advance, normally by the end of Mangsir, after discussion with the naike.

Most of these materials are simple and easily obtainable. Some technical details about the more complex items are given below.

Soil

For polypot seedlings especially, you will need to bring in large quantities of sandy loam or loam forest topsoil. If only heavy soils such as clays are available, they will have to be mixed with sand.

SOIL TEXTURE TEST

You can tell when the soil texture is right by trying to roll a little moist soil to pencil thickness between your fingers. If this is not possible, there is too much sand. If the roll can be bent in a semi-circle without breaking, there is too much clay.

Certain species of trees have special requirements for micro-biological soil constituents. To satisfy these, you need to try to collect soil from under existing stands of the trees concerned. The species in this category are given below; of all of them, it is most important that soil for pine seedlings comes from under pine trees (the other species usually grow reasonably well without the relevant microbes).

Pines (salla) require special mycorrhizal soil1.

The legume genera Acacia (e.g. khayer), Albizia (siris) and Dalbergia (sisau) require soil containing Rhizobium bacteria2.

The genus Alnus (utis) requires soil containing Frankia3.

1 Mycorrhizae are a living arrangement produced between special fungi and the roots of a plant, which increase the growth of the plant considerably. This is a form of symbiosis, where two organisms live together for mutual benefit. Soils from pine forests contain the necessary fungi to bring this about.

2 Rhizobia are the nitrogen-fixing bacteria that form nodules on the roots of many leguminous species, including those listed here.

3 Frankia are actinomycetes that form a symbiotic relationship with the roots of certain species, and which also fix nitrogen.

The quantity of soil required is often under-estimated. A nursery with a target of 10,000 usable plants would fill 12,500 pots. For 100 × 175 mm (4" × 7" inch) pots, this would require 6.1 cu. m of potting mixture. For a 2:1:1 soil: sand: compost mixture you would need about 3.1 cu. m of soil and 1.6 cu. m of sand, which would weigh about 4.5 and 2.7 tonnes. If sieving was done in the nursery you need 15 percent more soil and 5 percent more sand.

Compost

Details of the making and use of compost are given in Section 4.6. Compost is used to enrich the soil in the nursery beds.

Seeds

Seed collection and storage is covered in Section 4.7.

Grass slips

The collection and propagation of grasses from slips are covered in Section 4.3.

Hardwood cuttings

The propagation of shrubs and trees from hardwood cuttings is covered in Section 4.4.

Bamboo cuttings

The propagation of bamboos in nurseries from single node culm cuttings is described in Section 4.5.

Registers

The use of nursery registers is described in Section 4.6. The register forms are given in Annex C.

Nursery staff

Each nursery normally requires a staff of one naike, one watchman and two labourers. During the peak nursery season of February to June (Magh to Ashad), the number of labourers may need to be increased to five.

The staff of bio-engineering nurseries should be drawn from rural areas, to ensure that they have a good understanding of how to handle delicate plants. Only naikes and specialist seed collectors are considered to be skilled workers. The abilities and roles of the various staff are given below.

Nursery naikes

Naikes (or nursery foremen) are each responsible for the operation of one nursery. They must understand all aspects of nursery work and be able to motivate labourers and keep them busy. Training is usually necessary, but this can either be done within the Division (perhaps by the Supervisor), by attachment to another Division with a well-established nursery, or with help from the Geo-Environmental Unit. Literacy (in Nepali) is required for record keeping. The Naike should work full time in his nursery and manage his team of labourers. Duties include:

1 Daily operation of the nursery and attendance to all matters concerned with keeping a clean and healthy environment for seedlings and plants to thrive in.

2 Carrying out with due care all nursery operations.

3 Reporting to the local and senior road line supervisors any problems of plant health or growth.

4 In general, the provision of quality planting material for use in roadside planting.

5 Keeping records of all nursery stock.

In summary, nursery naikes should have the following attributes:

· good understanding of local plants;
· experience in nursery work;
· very active in the nursery at all times;
· knowledge of seed collection, treatment and storage;
· know how to motivate others.

Nursery watchmen

Anyone employed as a watchman has to be thoroughly trustworthy. He will be working alone all the time and has to be sufficiently motivated to work long hours in uncomfortable conditions. He should be in the nursery 12 hours a day or night, seven days a week. The best watchmen are usually the most reliable of the labour force and may be non-literate and poorly educated. In summary, nursery watchmen should have the following attributes:

· reliable and trustworthy;
· intelligent approach to work and show initiative;
· self motivated.

Labourers

Whenever possible, employ local farmers as labourers as they have a good understanding of plants. They should be from as close to the nursery or work site as possible. There is no need for literacy, but a good level of intelligence helps a lot. In summary, nursery labourers should have the following attributes:

· local farmers;
· good understanding of local plants;
· reliable.

Seed collectors

Seed collection requires skilled personnel who have been specifically trained for the job. There are three distinct elements: timing of seed collection and selection of good seed trees; ability to climb trees safely and pick the seeds; and knowledge of seed treatment and storage. People selected for this job should, therefore, be experienced, with a sound knowledge of local trees.

Some literacy is useful for reading training information and seed-collection calendars. In summary, seed collectors should have the following attributes:

· good understanding of local plants;
· knowledge of seed collection, treatment and storage;
· specially trained in tree climbing and seed collection.

In practice, each Division or project is unlikely to have specially trained seed collectors. Instead, labourers who are particularly good at this can be retained on the payroll to ensure that they are always available.

Tree climbing equipment can be partly purchased and partly made in the nursery. The Department of Forests sometimes gives training courses on making equipment.

The following questions can be used when interviewing people who are possible employees as nursery naikes, watchmen and labourers.

· Have they worked in the subject area before? For how long? Where?
· Have they ever done anything beyond the normal requirements of their job? What?
· How can you show a previous interest in or commitment to this job?
· What do they know about this job and why do they think they can do it?
· What tasks required in this job have they actually performed before?
· Have they ever worked in a team before? To do what?
· Have they ever organised others to work before?
· Have they ever had a bad accident or injured anyone? How?
· Do they live locally? Where exactly?
· How much land do they have? What do they grow on it? Do they have many private trees?
· Why did they leave their last job?
· How many days per month do they take off?
· Ask them to show you a khukuri or hasiya; if it is sharp and in good condition, the person should know how to look after their tools.

4.3 Propagation of grasses

This section explains how to produce grass plants in simple soil beds in a nursery.

Introduction: the methods of grass production

Perennial grasses usually form the main part of a bio-engineering scheme. Propagating these grasses vegetatively (i.e. from cuttings) is not difficult technically and various vegetative methods of propagation are highly successful. However, the reason for using a particular propagation method in the nursery is often related to the availability of material.

There are three methods for propagating grasses in bio-engineering, as described in Figure 4.6. Some grasses (e.g. dubo and kikiyu) can also be propagated from stolon cuttings1, but these are not normally used in bio-engineering. Seed is a cheap means of propagating grasses, but requires much longer growing in the nursery before the plants can be used on site.

1 A stolon is a stem that grows along the ground, producing at its nodes new plants with roots and upright stems.

Grasses from cuttings always grow much faster than those produced from seed. Also, they are tougher and do not go through such a delicate stage as seedlings.

Propagation of grasses from slip and rhizome cuttings

All of the bio-engineering grasses can be propagated by this method. It is by far the most widely used method of propagation in bio-engineering.


Grass clumps are split up and trimmed.


Grass clumps are split up to make slips.


Slips are then planted in nursery beds to multiply.

Take a clump of the grass, cut the shoots off about 100 to 150 mm above the ground and then split the whole clump carefully into sections. Each section should include several old shoots, any new buds that are visible and as much root as possible. You need to balance getting the maximum number of transplants from one clump while making sure each is a viable plant.

When you are planting the slips, bury the root parts carefully into loose, moist soil, trying to keep them as straight as possible and about 20 mm below the surface. If they are more shallow they may dry out. The tops can be either at an angle or vertical. After planting, lay a sheet of hessian over the tops of the cuttings to give shade. Keep it there until the new shoots are about 50 mm long and then remove it in stages, starting by removing the hessian for a few hours a day.

Rhizome cuttings

Some grasses have a rhizome system (e.g. amliso and the small bamboos, padang and tite nigalo). The method involves making a slip, which includes part of the rhizome.

Take a clump of the grass and cut off the shoots above the first or second node above the ground. Separate the clump, taking care not to damage the rhizomes and fine roots. Keep at least 50 mm of the rhizome, or horizontal part, per cutting. Each cutting should have some buds at the nodes on the rhizome, but often these are difficult to see. The new growth will come from these buds. When you plant the slip, keep the level of the soil as it was originally, making sure the rhizome is well covered. The method of planting and covering is similar to that of other slip cuttings.

Propagation of grasses from culm or stem cuttings

This is suitable for grasses that have heavy branching, such as dhonde and narkat. Usually, a piece of stem with at least two or three nodes is used, but the most vigorous species, such as napier, can be propagated from single-node cuttings if material is scarce.

Select material that is between one and two years old. Cut the stem horizontally about 30 mm above the higher node and at 45° about 30 mm below the lower node. The different cuts help you to tell at a glance which way up the cutting should be planted.

Insert the cutting into loosened, moist soil, so that it is two-thirds buried. Cuttings can be inserted at an angle of about 45° but vertical insertion is also acceptable. Many plants survive equally well if cuttings are planted horizontally. Often the upper node gives shoots and the lower node gives roots, but a large, strong shoot may also emerge from the lower node.

After planting, lay a sheet of hessian over the tops of the cuttings to give shade. Keep it in place until the new shoots are about 50 mm long, and then remove it in stages, starting by removing the hessian for a few hours a day.

Stolon cuttings

If the grass produces a stolon, it is usually possible to make cuttings from the individual nodes. This is particularly easy with dubo and kikiyu.

Often, roots grow naturally from the nodes on the stolon. This is called 'layering'. If this happens you only have to cut the stolon mid-way between the nodes and carefully transplant it with its roots and shoots intact. It is already a new plant. If roots have not yet appeared, you can cut off a node and plant it not more than 10 mm below the surface. Keep any leaves attached to it and plant the cutting with them above the ground. Avoid damaging any shoots or buds that exist. The node will shoot and root very quickly.

Figure 4.6: Propagation methods for bio-engineering grasses

PROPAGATION METHODS

DESCRIPTION

MAIN SPECIES

Slip cuttings

The main method of propagating grasses for bio-engineering. Rooted cuttings are made by splitting out grass clumps grown in the nursery. If the grass is rhizomatous (like amliso or tite nigalo), then the slip consists of a section of the rhizome and some shoots, and must include root buds

All bio-engineering grass species

Stem cuttings

Propagation by planting a section of the stem, usually with two nodes and a section of culm. This is carried out either in the nursery for transplanting as a rooted cutting, or directly on site

Dhonde, napier, narkat

Seeds

Grass plants are grown up from seeds. This is carried out either in the nursery for transplanting as a rooted plant, or directly on site

Babiyo, dhonde, kans, katara khar, khar, phurke, sito

Propagation of grasses from seeds

Most grass seeds will remain viable for several years, but you should use them within one year if possible.

Sow the whole remains of the seed heads on the surface of a recently cultivated bed. Dense sowing is usually the best method (i.e. 25 g of seed per 1 sq. m of bed), so that several thousand seeds germinate per square metre.

Very young grass seedlings can be scorched by the sun and killed if they do not have enough shade. Avoid this problem by covering them with a sheet of dampened hessian. Similarly, spreading a layer of dampened hessian jute over newly sown seeds can protect them from intense heat. Keep the jute damp as much as possible, because very intense sun can dry out the surface even underneath it. Remove the hessian in stages once the seedling stems are about 10 mm long. First remove it for a few hours during the early morning and late afternoon, then for longer, and finally completely. Thin the seedlings heavily from time to time.

Most of the soil conservation grasses require warmth before the seeds will germinate. This may be an in-built survival mechanism, as small seeds do not have very big reserves. In order to overcome this problem, do not sow too early. If you have to sow early, you can use cloches1 to increase the temperature in the seed bed.

1 A temporary tunnel of clear polythene sheeting used in nurseries and horticulture farms during the winter. The tunnel produces a warm, sheltered microclimate around young plants.

A cloche is made by placing bamboo hoops across the bed and covering the bed with polythene, which is kept well clear of the seeds.

Management of grasses in the nursery

Keep grass beds well watered and weeded. Replant any gaps where plants have failed as soon as possible. Grass seedlings will need to be thinned heavily every week or so, to allow clumps to develop. Eventually you should aim to have 100 plants per square metre.

When grasses grown from slips have grown up and completely filled the beds, there are two options. The usual one is to cut the shoots off about 150 mm above the soil, to encourage the development of new shoots. However, if the planting season is a long time off, you can lift the grasses out, split them up and replant them. One bed of large plants ready for splitting usually fills three to seven beds after transplantation.


Grass beds in a bio-engineering nursery

4.4 Propagation of shrubs and trees

This section explains how to grow shrubs and trees2 in a nursery, starting from either seed or from hardwood cuttings.

2 A shrub is a woody plant with multiple stems growing up from the ground; a tree has usually one stem growing up from the ground. For bio-engineering purposes, shrubs and small-stature trees have the same functions.

Introduction: methods of shrub and tree production

There are many ways of propagating shrubs and trees. Although this is a very specialised activity the bio-engineering species have been chosen partly for ease of propagation. In the road sector, two main methods are used: polypot seedlings and hardwood cuttings. A third method (stump cuttings) is particularly useful for sisau and some other species, and is also described here (see Figure 4.7 for a summary of these methods).

Polypot seedlings

There are distinct steps in the production of seedlings in polythene pots ('polypots') (see Figure 4.8). These depend on the size of the seed, and whether they need to be sown into a seed bed, or can be sown directly into the polypots.

Figure 4.7: Propagation methods for shrubs and trees

PROPAGATION METHODS

DESCRIPTION

MAIN SPECIES

Polypot seedlings

Plants are raised from seed in a nursery. They are grown on in polythene containers ('polypots'), and also moved in them to site for final transplanting. If the seed is reasonably large (e.g. khayer or sisau), it is sown directly into the prepared polypot. If it is very small, however, like utis seed, it is sown in a seed bed and later is pricked out to the polypot

Areri, dhanyero, dhusun, keraukose, bakaino, chilaune, gobre salla, kalo siris, khanyu, khayer, lankuri, painyu, khote salla, rato siris, seto siris, sisau, utis

Hardwood cuttings

A section of woody stem (a 'cutting') is cut from a parent plant and inserted into the soil. From the buds on the cutting, shoots and roots develop to form a new plant. This is usually done on site but, in some cases, it is done in the nursery, and the entire rooted plant moved to site later on. Techniques such as brush layering (Section 3.10) and palisades (Section 3.11) use hardwood cuttings

Assuro, bainsh, kanda phul, namdi phul, saruwa/bihaya, simali, dabdabe, phaledo

Stump cuttings

'Stumps' are cuttings consisting of sections of the plant that include both root and shoot. They are made from seedlings more than one year old raised in soil beds (e.g. standard nursery grass beds)

Sisau

Direct seeding

Plants are sown directly on site, either by broadcasting small seeds across the surface, or by inserting larger seeds directly into the soil. This technique is described in detail in Section 3.8. It does not involve a nursery stage

Broadcasting: khanyu, utis; direct seeding: areri, bhujetro

Root suckers

Some plants put out new shoots from the root level: banana trees are a common example. You can propagate new plants by digging around the existing plant and separating off the new shoot or 'sucker' growing from the roots. This technique does not involve a nursery stage

Kettuke

Budding, grafting and layering

These are specialist techniques used mostly in horticulture and the production of high-yielding fodder trees. Budding and grafting combine different plants for specific properties. For example, one plant may contribute better root stock to fruit or fodder trees. Layering encourages the development of roots from a node on a branch, which is then separated to form a new plant.

Not normally used in bio-engineering

Preparing seed beds.

See Section 4.1.

Polypots

Polypots should have the following attributes.

Material: 200 gauge (0.05 mm thick) black polythene.
Size: 4" × 7" laid flat.
Drainage holes: 8 to 12 holes, about 5-6 mm in diameter, in the lower third of the pot; corners may also be cut off.

Potting mixture in polypots

Use only topsoil with the texture of sandy loam or loamy sand (40 to 70 per cent sand). You can identify these soils by trying to roll a little moist soil to pencil thickness between your fingers. If this is not possible, there is too much sand. If the roll can be bent in a semi-circle without breaking, there is too much clay. Add washed sand as required to improve the soil texture. Add sieved, well-rotted compost to improve the fertility and moisture retention.

An ideal potting mixture has the following characteristics:

· light weight;
· homogeneous;
· easily available;
· fertile, and retains nutrients well;
· a pH between 4.5 and 6.0;
· well drained, but retains sufficient moisture;
· sufficiently cohesive to maintain the root ball after removal from a polypot.

Soil for growing pines must be collected from a pine forest. Alternatively, add mycorrhizal soil to the potting mixture. If possible, when propagating khayer, siris, sisau or utis, soil should be used from forests of these species; however, this is not as critical as it is for pines.

Filling polypots

When the mixture of soil/sand/compost is ready you can fill the polypots by hand. A scoop made from an old half-litre plastic bottle will help speed up the process. Make the mixture very slightly moist, but keep it loose so that you can easily pour it. Fill the pot in three or four stages, firming down the mixture after each stage. Do not fill the whole pot and then try to firm all the soil at once, because this leaves air pockets. Fill the pot completely. Allow the mixture to settle for about four weeks. Do not allow the pots to dry out during this period. Water them periodically to permit the development of micro-organisms. This is especially important if the soil has been stored dry for some time. The pots are then ready to take seeds or transplants.


Figure 4.8: The main steps in producing polypot seedlings

Preparing seeds

Most species used for bio-engineering have seeds that will germinate quickly when sown. Others may take several months to germinate unless they are treated properly. Such seeds are said to be dormant. There are several ways to overcome dormancy, depending on the species. These are summarised in Figure 4.9.

Sowing small seeds in seed beds.

Estimate the sowing density so there will be about 4,000 seedlings per sq. m. Taking khanyu as an example, there are about 1,500,000 seeds per kg. Assume an effective germination of 25 per cent (the percentage is low because experience has shown that naikes have great difficulty in germinating very small seeds). If 25 per cent of 1 g of seed (i.e. about 1,500 seeds) germinates, we can expect 375 seedlings. Dividing the desired seedling density (i.e. 4,000/sq. m) by 375 gives the weight of seed to sow on 1 sq. m as 10.67 g.

Press down the soil with a small block and water it. The surface must be perfectly level. Mix small seed with two or three times its volume of clean, fine, dry sand. Then broadcast the seed/sand mixture over the surface. Distribute the seed/sand evenly by placing it on a flat piece of card, holding this just above the soil and tapping it lightly underneath. The seed bounces off, making it easier to control its distribution.

After sowing, cover the seed evenly with pure washed sand. Use just enough to cover the seed. Make the seed cover firm with a wooden block, cover lightly with a mulch of rice husks, pine needles or straw and water the tray with a watering can fitted with a fine rose. The mulch will prevent the seed from drying out. Protect the bed or tray from heavy rain with a strong shade.

Small seeds must not be allowed to dry out, so you must inspect the beds several times a day and water when necessary. However, too much water will also reduce germination.

When germination is nearly finished, remove the mulch and expose the seedlings to full light for a few hours each day. If the soil becomes too wet, or if damping off becomes a problem, allow them to dry out a little by reducing the amount of shade.


Polypots are filled with a fertile topsoil of loamy or sandy loam texture


Polypots are filled with a fertile topsoil of loamy or sandy loam texture and placed in standout beds

Pricking out

This is the process of transferring seedlings from the seed beds to polypots. It is a very delicate operation that should be done with great care, preferably by experienced workers. Prick out shortly after germination, when the seedlings have only three or four primary leaves in addition to the cotyledons1. Pine seedlings can be pricked out three or four days after germination, when the seed coat is still attached to the cotyledons giving the appearance of a match-stick. Do the pricking out on a cloudy day or in the late afternoon or evening.

1 Part of the embryo of a seed plant. The cotyledon often becomes the first photosynthetic (green, light-gathering) organ of the young seedling.

When the seedlings have started to produce new leaves, start to remove the shade as explained in Section 4.6. Generally, after about a week no shade should be given.

Sowing larger seeds directly into polypots

Thoroughly water the pots the evening before sowing, and lightly water again immediately before sowing. Sow two seeds in each pot. Push the seeds into the soil surface in the centre of the pot and cover it with sand. Never sow seed deeper than twice its width and in any case not more than 5 mm deep. Shade the pots and water them again.

Re-spacing seedlings between polypots

After germination, pots will have 0, 1 or 2 seedlings each. When germination is almost finished, prick out plants from pots that have more than one into pots without any. This may still leave some pots with more than one seedling. Remove the extra plants, once germination and pricking out have been successfully completed, by pulling them up or by breaking or cutting the stem near soil level.

Shading and watering

These are covered in Section 4.6.

Figure 4.9: Pre-sowing treatments for the main bio-engineering shrubs and trees

TREATMENT

SHRUB SPECIES

TREE SPECIES

No treatment required; just sow

Areri, bhujetro, dhanyero, dhusun, keraukose, tilka

Chilaune, gobre salla, khanyu, khote salla, utis

Soak in warm water for 24 hours before sowing

-

Bakaino, painyu, sisau

Chipping: cut off a small piece of the seed coat with nail clippers on the side of the seed opposite the hilum (the scar from which the seedling root emerges

-

Kalo siris, khayer, rato siris, seto siris

Avoid dormancy by sowing immediately

-

Lankuri (green)

Keep over a winter before sowing

-

Lankuri (brown)

Spacing out polypot seedlings

Plants growing close together in the nursery compete for moisture, nutrients and light. Their growth and form is affected and they become tall and thin, with weak, soft stems and poorly developed root systems. Plants grown in 4" × 7" pots to a height of over 300 mm do not have enough growing space.

When plants reach a height of 300 mm, separate the rows of pots across the bed, leaving a space of up to 100 mm between them. You can make the spaces with wooden sticks, bamboo laths, bricks, stones, or old filled polypots without seedlings. Spacing between plants within the rows is not necessary. Spacing requires more bed area in the nursery and you must consider this in planning bed sizes. Where insufficient area is available, spacing only between pairs of rows is a reasonable compromise.

Root-pruning polypot seedlings

Root pruning prevents the formation of very long roots in the nursery, which would have to be cut when the plants are transferred to the field, increasing the shock to the seedling. It also reduces excessive shoot growth, increases the hardening of the stem and increases the development of lateral roots.

Check the need for root pruning by lifting a few pots; if roots are seen protruding from the bases, all the pots in the bed should be checked.

Roots should be trimmed off just below the pot, using a razor blade or a sharp khukuri. If root-pruning causes the plant to wilt slightly, it has been done at the right time.


Proper spacing of polypots minimises competition for moisture, nutrients and light

As with watering, root-pruning cannot be carried out according to a fixed timetable but must be done according to the needs of the plant, as ascertained by frequent checks.

Preparing and packing polypots for transport

These are covered in Section 4.6.

Hardwood cuttings

Rooting hardwood cuttings is the easiest and cheapest way of propagating plants vegetatively. Make cuttings from wood of the previous season's growth or sometimes of the one before. Never use older wood because this does not develop roots easily. Use material from branches in the lower part of the tree crown, but not from the main shoots or other outer parts of these branches. Even better, take cuttings from stool shoots produced in the nursery for this purpose (see below).

HOW TO PRICK SEEDLINGS OUT SUCCESSFULLY

Use the following procedure for good survival after pricking out:

1. One day before, thoroughly water the polypots into which the seedlings will be pricked out. Ensure that shades are erected and in good order.

2. Immediately before starting to prick out, lightly water the seedbeds.

3. Remove the seedlings from the seedbeds by inserting a flat stick under them and gently lifting. Take care to do as little damage as possible to the roots. Hold the seedlings by the leaves or cotyledons. Never touch the stem or roots.

4. Take just enough seedlings for about fifteen minutes pricking out, and keep them in a dish of water. Keep this shaded so that the water does not heat up rapidly in the sun and kill the seedlings. Do not let the roots dry out.

5. Make a hole in the soil, in the centre of the polypot, with a pointed wooden stick a little thicker than a pencil. The hole must be deep, and wide enough to contain the seedling's roots without bending them.

6. Hold the seedling's root in the hole with the root collar just below the soil surface. Do not bend the roots into a J or U shape. If any of the roots are too long, cut them to the desired length with your finger nails or a sharp blade. Do not leave the primary leaves in contact with the soil surface.

7. Insert the stick used for making the hole about 10 mm from the roots and close the hole around the root by levering the stick gently back and forth. Be careful to close the hole throughout its depth, and not just at the top.

8. Lightly water the seedlings and ensure that the soil around the roots remains fairly moist but not saturated, as this would lead to rotting, by lightly watering tow or three limes a day for the next few days. Keep the shades on throughout this period.


9. Three or four days after pricking out, replace any plants that have died, by repeat-ting the above procedure.

Prepare cuttings just before the buds open, usually from mid-January to mid-April (Magh to Chaitra), from healthy vigorous stems or branches. Do not use weak stems. The cuttings should be about 150 - 200 mm long, 8 - 20 mm diameter, with at least two, and preferably three or four, nodes. Make a horizontal cut 10 to 30 mm above the upper node and a sloping cut just below the lowest node with secateurs, a sharp khukuri or similar blade. Avoid crushing, splitting or otherwise damaging the ends. Cut off all leaves and side branches.

Prepare the cuttings the same day you collect the shoots and set them immediately into pots or beds that have been prepared in advance. Cuttings that are allowed to dry out will not form roots.

You can root cuttings in large polypots (not less than 4" × 7"), or in previously prepared nursery beds (e.g. standard nursery grass beds).

In beds, set the cuttings 300 mm apart, in holes slightly larger than their diameter, placing them so that only one bud, i.e. about 30 mm of the cutting, remains above the soil level. Firm the soil up so that there are no air pockets around the cutting. Use the same method for polypots, but finish by rolling the pot between your hands to firm up the soil.

Water the beds or pots and shade them immediately after setting. Keep them constantly moist, but not too wet, until well after root formation. If the soil becomes too wet, remove the shade for a few hours, but not long enough to permit the soil to dry out completely.

New shoots will develop a few weeks after setting, and will cause increased loss of water through transpiration. Maintain shade to minimise this loss until fully functioning roots have formed. Sometimes success is suggested by the development of healthy vigorous shoots, but they dry up and die if there is no equally vigorous development of roots. Remove the shade once the roots are well developed (i.e. when they start to grow from the bottom of the pots and you have to begin root pruning).

In nurseries at lower elevations, and with faster growing species, rooted cuttings reach the required size for planting by the beginning of the monsoon (five months after setting). In other cases it may be necessary to keep them in the nursery until the following monsoon.

You can produce young material ideal for hardwood cuttings in the nursery by establishing stool beds. Plant 20 to 50 plants of each of two or three species in a soil bed (i.e. a standard grass bed) and cut them back each year so they produce plants from which cuttings can be made. This makes collecting cutting material easy, saves a lot of time, and ensures that juvenile material is used.

Stump cuttings

Stumps are a form of cutting used in the propagation of certain trees, notably sisau. The advantage of this technique is that the plant leaving the nursery is smaller and easier to transport.

Prepare the ground for the stump beds as for standard nursery grass beds. Sow the seeds directly into the beds, in lines 100 mm apart. Water to keep the soil moist. Shade the seedlings until they are well developed and about 50 to 100 mm tall. Once they have reached this size, thin them out to give a spacing of one plant per 150 mm in the lines. To thin the plants, gently uproot the unwanted seedlings or break them off at the root collar1. Take care not to disturb the plants that are to be left.

1 The root collar of a seedling is the line below which the roots emerge. It normally corresponds with the surface of the soil and often shows a change of colour or a slight swelling.

Allow the plants to grow on after the first monsoon. They will not need as much watering during the second dry season.

The stumps will be required for site planting during the second monsoon after sowing, when the plants are about 15 months old. Sisau should be 1.5 to 2.5 metres in height by this time.

To make the stumps, start by uprooting the plants carefully. Cut the tap roots about 300 mm below the surface level. Then make the stump cutting itself, using a sharp khukuri. Cut the stem about 50 mm above the root collar and cut the tap root about 250 mm below the root collar. Trim any side roots about 10 mm from the main root. Cuttings should be within the diameter range of 7 to 15 mm (between the thickness of a pencil and your thumb) at the root collar. Discard any badly misshapen or damaged cuttings. Wrap the cuttings in damp hessian for transporting to site.

4.5 Propagation of bamboos

Introduction: the methods of bamboo production

Bamboos are large grasses. They are relatively slower growing and harder to establish than the smaller grasses, and tend to grow in damper locations. But once they are established, the big bamboos form huge plants, which are especially useful for catching debris and supporting the slope.

Bamboos do not often seed and so they are normally propagated from big cuttings. To do this, there are two main methods used in Nepal (Figure 4.10 summarises these). The traditional method is commonly known in rural areas but is a big undertaking for large bamboos, and therefore expensive. Some species can be propagated from single-node culm cuttings, but this requires a long period in the nursery.

The traditional method of bamboo propagation does not involve a period in the nursery. This process is described in Section 3.9.

Propagation of bamboos from single-node culm cuttings

Rooted culm cuttings are relatively cheap, easy to transport and survive well after planting.

Equipment required

A sharp tool like a khukuri or hasiya is sufficient, but a handsaw and secateurs, for pruning branches, are useful if they are available.

Selection of materials

Only use choya/tama, dhanu or kalo bans for this method. Take cuttings from culms in their second year of growth. If such culms are not available you can use third-year culms. Culms less than one year old are not strong enough to give cuttings. Choose healthy culms with strong branches. Avoid damaging the dormant buds in the central branches at nodes. Select suitable culms one year in advance and mark them.

Time for taking cuttings

The best months for taking culm cuttings are February and March (mid Magh to mid Chaitra). Take the cuttings when the buds are ready to burst but before new growth starts. In hotter places take them earlier, generally in February (mid Magh to mid Falgun), whereas in cooler places March is best (mid Falgun to mid Chaitra).

Preparation of cuttings

Prepare the cuttings where you obtain the culms. Cut the culms midway between the nodes without splitting them, so that all the cuttings are single-noded. Cut off the leaves and small branches as close as possible to the culm. Reject material less than 40 mm in diameter from the tops of culms. Prune central branches off beyond the first node. You can take cuttings from culms whose buds are completely dormant or with undeveloped central branches. Dip the cuttings into water or sprinkle them with water immediately after preparation.

Transport

After you have prepared cuttings at the bamboo clump bring them to the nursery. Do not allow them to dry out during transport. If they are kept in a doko or any other container, pour water on them. Cover them fully with leaves and grass or wet sacks.

Preparation of beds

The best place to set culm cuttings is the coolest, dampest and shadiest part of the nursery. Prepare the beds as described for bamboo cuttings in Figure 4.5. Water the beds thoroughly before and after setting the cuttings. Good facilities for watering are essential. Provide shades all the year round.

Setting

Plant the cuttings horizontally with the large central branch, or the bud from which it will come, sideways at the soil surface. The main bud at the first node of the central branch should be facing upwards. Ensure that the ends of the culms are well covered with soil because all the water needed for the development of the cutting enters through the cut ends of the culm for at least the first two months. If the ends are allowed to dry out, success rates will be reduced.

If the cuttings obtain enough water from the beds and do not dry out, shoots will develop in one to three weeks. Most of those shoots will grow to about a metre in height and produce leafy branches before beginning to root after about three months. The cuttings must be watered well and shaded throughout this period and beyond.


Setting a single node bamboo cutting in a saturated bed

Planting out

Below 1500 metres, keep the cuttings in the nursery for 16 months; above 1500 metres, keep them in for 28 months. After 16 or 28 months in the nursery, culm cuttings that have many rhizomes with more than three shoots will be ready for planting. This will be in June or July (Ashad), when the monsoon rain starts. The recommended height of bamboo plants is at least 2 m, but if the planting site is far away you can cut them back to 0.5 metre for ease of transport. Take precautions to ensure that they will not dry out while being transported. Wrap the rhizomes well in a sack full of wet soil. Make sure the rhizomes are not damaged. Cut most of the remaining leaves in half to reduce transpiration.

Dig a large pit and plant the rooted cutting carefully. Add compost to the soil if it is available. Mulch the area around the plant well. If there is no rain, water it during the first few weeks after planting. See Section 5.3 (Mulching) for more details on mulching.

Survival rates of plants

Grasses propagated by slip should give a survival rate of almost 100 percent in the nursery and about 95 percent on site. If there are significantly more failures than this, then you should investigate the possible reasons. The most common reasons are that the slips were allowed to dry out at some stage during the transplanting process.

Grasses propagated by rhizome cuttings have a slightly lower survival rate. However, this should still exceed 95 percent in the nursery and 90 percent on site. Failures greater than these should be investigated.

Where grasses are grown from seed, it is almost impossible to estimate the survival rate. However, if the standard application rates are used, there should be a thick, even cover of grasses resulting. If this does not occur, the usual causes are from sowing too early or from seeds being washed off the surface.

Shrubs and trees have to be considered separately. In nurseries it is normal to plant more cuttings or to sow more seeds than are required because, however good the nursery staff, there will inevitably be significant losses. The processes of taking from cuttings or germinating, transplanting and growing on, all take a toll on the young plants.

It is normal practice to allow four times the amount of seed for the final number of seedlings required.

It is normal practice to grow up 25 percent more seedlings than will be required, and to discard the poorer plants when they leave the nursery.

Therefore, for every 100 seedlings used on site, 400 seeds will have been sown and 125 seedlings will have been grown up.

Figure 4.10: Propagation methods for bamboos

PROPAGATION METHODS

DESCRIPTION

MAIN SPECIES

Traditional method

A section of rooted rhizome and an entire culm is cut out of an established bamboo clump. It is replanted with the culm cut off about 2 metres above the ground, leaving branches emerging from one or two of the nodes.

All bamboos

Rooted single-node culm cuttings

A single node of a bamboo culm is planted in a wet, well-shaded nursery bed and allowed to root over a period of at least one year. It is then transported for planting on site as a newly rooted plant.

Choya/tama, dhanu or kalo bans

Other methods

Bamboos can occasionally be grown from seed, but only if seeds have been obtained (bamboos produce seeds only about once in 20 years). Other cutting methods and advanced techniques such as tissue culture have not proved successful in Nepal on a widespread basis.


On site, the survival rates for shrubs and trees can vary considerably depending on the biophysical harshness of the site, the quality of the plants and the quality of the planting works. In forestry plantations in Nepal, survival of only 80 percent is considered acceptable, although it should be much more. The same rate should be used for bio-engineering works. If less than 80 percent survive, then a thorough investigation should be made. The usual causes of casualties are from careless handling and planting on site, and subsequent grazing damage.

4.6 Nursery management

The management of nurseries, beyond what has already been described in previous sections, consists of:

· environment management (which means controlling shade and water);
· restriction of pests and diseases;
· preparing plants to leave the nursery;
· use of registers; and
· making and using compost.

Shading

Plants in all nurseries in Nepal require shading at some stage. It is needed for a variety of reasons at different stages of growth, but must be done carefully. The wrong use of shades can be damaging to young plants.

However, shading is only required on a very temporary basis. It is usually needed during germination, for protecting recently pricked out seedlings, and for protection against adverse climatic conditions such as excessively hot sun, heavy rain, hail, or frost.

Making shades

Make shades of locally available materials. They should be easy for one person to handle. They must be movable but capable of being fixed to prevent them blowing away in strong winds. The height of the shade depends on its use. It should be about 300 mm above seedbeds and recently pricked out seedlings, and 750 mm above ground level for protecting larger seedlings against hail, hot sun and heavy rain. Construct beds along an east-west line if possible and arrange the shade so that it slopes downwards from north to south.

The slope carries water off and the alignment gives maximum protection against the mid-day sun.

Complete shades can be made from woven bamboo matting, hessian cloth or the stalks of maize or wheat. They should be wide enough to overhang the bed slightly and can be up to two metres long. Longer lasting shades can be made from wooden or bamboo slats tied together with spaces between them to allow some light and air to penetrate. They can be rolled up for easy storage and unrolled very quickly when needed. They are heavy enough not to need fixing. Polythene sheets can be spread over them to make them waterproof when necessary.

Shading from hot sun

This is used for seeds and young plants. Shade helps germinating plants because it slows the drying out of the growing medium and the seed. It also prevents damage from rain. Shade over germinating seed should be waterproof. Polypot seedlings also require shade for a few days only after they have been pricked out, to protect them from the sun and to keep the soil moist. The amount of shade needed during germination and after pricking out varies with the weather. If it is used when it is not necessary, for example during spells of cool cloudy weather, the beds may become too moist and this often leads to the development of damping-off disease.

Removing shades from young seedlings.

Remove shades gradually, starting as soon as new leaf development is seen. At first, take the shades off for a short time in the morning and afternoon, keeping them in place at the hottest times.


All plants need shade at some stage of their growth. These shades can easily be removed when necessary

Gradually increase the time they are removed each day until after about a week the shade can be completely removed, without causing any damage to the plants.

Heavy rain

During the monsoon, shade for protection against the rain should only be used when it is actually raining heavily, or at night or during the day when staff are absent.

Hail

Hail usually occurs in the months immediately before the monsoon (Chaitra to Jestha) and during this period shades should be erected at night or when staff are absent from the nursery during the day. When the nursery staff are present they should only erect the shades when a storm is seen to be coming.

Frost

In higher altitude nurseries during the winter, if there is a danger of frost, erect shades each evening and remove them early the following morning. Do not leave them on all day at this season. Frost protection shades are most effective when they are just a few centimetres above the plants.

Shading bamboo beds

Bamboo culm cuttings need complete shade. This can be achieved by hanging sheets of hessian along the sides of the shade structures. The structures should also be higher, giving about 1.5 metres clearance above the soil, as the plants can grow to be quite large.


Cloches provide a warm, sheltered microclimate for growth early in the season

Cloches

Cloches are tunnels of clear polythene that are placed over nursery beds to raise the temperature during cooler weather. They are constructed by placing semi-circular hoops, made from split bamboo or the branch of a tree, every one to two metres along the bed. The polythene is then stretched over the hoops and weighed down at the sides and ends using stones or soil.

On sunny days the micro-climate inside the cloche can become very warm. The danger is that it can also become very humid and airless. For this reason, cloches must be opened out for at least one hour, twice per day, to ensure that fungi do not thrive inside them.

Cloches are often used in horticulture for speeding up the rate of vegetable production. They are extremely useful in higher altitude nurseries, as they can increase the growing season greatly at very little cost.

Watering

Watering in most small nurseries is done with 8-litre watering cans or a hose pipe with a watering rose, fed from a raised tank. These are the most appropriate and efficient methods. Careless watering can severely damage young plants.

There are no rules for watering, as the amount and frequency of watering required varies with weather conditions, species, the stage of development of the plants, soil type, and nursery management such as the use of shade. An inexperienced naike cannot be expected to know how often and how heavily to water. It is far better to teach the naike the basic principles of plant water requirements; a good naike will quickly learn from experience.

Keep seedbeds and recently pricked-out seedlings moist but never allow them to become saturated. This often means frequent, small applications of water, sometimes two or more per day. However, shading and mulching reduce the need for frequent watering. In cool, cloudy weather, water may not be required at all on some days. Check the beds periodically so that decisions can be made on the needs of the seeds or plants. Remember that the object is to keep the seeds or the seedling roots moist but not soaking wet. Always check the soil to the required depth before and after watering, to see if watering is required and if enough has been applied. Too much water can cause just as many problems as too little.

Weed, pest and disease control

Weeds

Weeds compete with plants for moisture, nutrients and light, and must be carefully controlled in the whole of the nursery area. If beds are weeded frequently, weeds will not have the chance to grow and weeding will take much less time. Their removal complete with roots is easy, and damage to the plants is minimised. Water the beds or pots before you start to weed, and pull the weeds out with their roots. If the roots cannot be pulled out, weeding has been started too late.

Keep the fence line, unused areas and paths free of weeds. Never leave weeds to flower and seed in any part of the nursery as this creates more problems and work later on. Weed throughout the year.

Insect and mammal pest control

Serious losses from insect damage are less common than losses from disease, but they are occasionally severe in some nurseries. Once again, prevention is better than cure.

Damage by insect larvae can lead to serious losses, especially just after germination. Some types live in the soil and come out to feed at night. They usually cut the stem of the young plant close to the soil surface, and they may also eat the leaves. Other types just eat the leaves. Where possible, it is best to control larvae by carefully examining the beds each day, picking off any that are found and squashing them. Insecticides containing methyl parathion, such as Metacid and Paramar are effective. Make a 0.05 per cent solution (i.e. mix 1 ml with 2 litres of water) and apply this with a watering can with a fine rose. You need to measure the very small quantities of chemical needed accurately, with a 4 ml hypodermic syringe.

Ants and 'white grubs1' will occasionally eat seed or attack seedlings. If this is a problem, sprinkle the area lightly with Aldrin dust. In the case of larvae, cultivate the Aldrin into the soil. However, Aldrin is a very hazardous chemical; do not use it unless you have to. When its use is unavoidable, take every possible care to minimise the risk of physical contact with the chemical.

1 Insect larvae that live in the soil and eat plant roots: they are large, thick, white larvae, usually C-shaped, and may be more than 30 mm long.

Rodents, cattle, goats, pigs, dogs and chickens must be completely excluded from the nursery by constant maintenance of the fence or wall and use of the normal deterrent and trapping methods.

Fungal diseases control

Two fungal diseases are important in nurseries in Nepal: damping-off and brown needle disease. The latter affects only pines, which are not used very widely in bio-engineering nurseries. Napier and Robbins discuss it in Forest Seed and Nursery Practice in Nepal.

'Damping-off' affects young seedlings. It may be caused by many different fungi, which are always present in soils. Good nursery management involves stopping them from killing seedlings. There are three types:

· pre-emergent damping-off, in which the fungus attacks the seed and the newly developing root before the shoot emerges from the soil. It can easily be confused with poor germination that is due to the seed having poor viability;

· post-emergent damping-off, in which the fungus attacks the base of the stem or roots after the seedling has emerged from the soil. The plant falls over and rots quickly. This usually occurs within 2 - 3 weeks of germination, while the stem is still soft. It is easy to recognise, but can be confused with insect damage to roots and the seedling stem-base. It often occurs in patches on the seedbed, with the most recently affected plants at the outside of the patch. It can spread very rapidly unless corrective action is taken as soon as it is noticed; all the plants in a seedbed can be killed within 48 hours;

· root rot affects older seedlings than the other two types. The first signs are yellowish (chlorotic) foliage in the upper leaves. This is followed by the wilting, discoloration and death of the shoot, after which the lower leaves may show signs of secondary fungal attack. Some of the roots will be seen to be soft and rotten or already dead. A good test is to see if the outer root layer can easily be pulled away from the inner core. Also, when healthy roots are broken, a sharp snap should be heard, but this will not happen if they are affected by root rot. Unfortunately, the first visible symptom of root rot, chlorosis, can be caused by many other problems such as a shortage of nutrients, too much or too little watering, or insect or nematode damage.

In bio-engineering nurseries, where soil sterilisation and extensive use of fungicides are not normally practised, prevention and control of damping-off depends on good nursery techniques. Damping-off fungi thrive in warm, moist, shady conditions and the most common cause is excessive moisture. This can be controlled. The naike should prevent damping-off by:

· not over-watering;
· removing shade as soon as it becomes unnecessary;
· not sowing seed too deep;
· where possible, sowing in the dry season;
· ensuring free air circulation over the beds;
· keeping the nursery free of weeds and old unmanaged seedlings;
· not including compost or fertilisers in the sowing medium;
· using a well drained, sandy medium;
· using pure sand as a seed cover;
· avoiding transplanting damage by always handling seedlings carefully, by the cotyledons or leaves and not by the stems or roots and, where possible, by sowing seed directly into polypots or stand-out beds.


Grass slips must be prepared carefully for use on site

If damping-off occurs, reduce watering, remove shade and, if possible, protect the plants from rain by moving the seed trays under cover, or covering the beds with plastic sheets, during heavy showers. Once the disease is established it is very difficult to control. Try to prevent it altogether, but if it does happen, act quickly to prevent it spreading.

If fungicides are available, they can be used to help prevent damping-off spreading to other plants but they will not have much effect once it is well developed. Mix 25 g of Blitox (a blue powder) with 5 litres of water, and apply to the affected plants with a watering can twice a week.

Preparing plants to leave the nursery

Hardening-off

In a nursery we try to produce ideal conditions for plant growth. When the plants are planted out on site, they often face conditions that are far from ideal. They may face strong competition from weeds. They may receive excess rain or suffer from an interruption in the rains. In the nursery we must get them accustomed to, and able to tolerate, more difficult conditions. This is achieved through the process known as 'hardening-off'. Its main features are:

· removal of shade at an early stage;
· spacing;
· reduction of watering.

Culling

There will always be some plants that are not good enough for planting out. Planting out poor seedlings is a waste of money and opportunity. It is perfectly normal to reject as many as 20 per cent of the plants in a bio-engineering nursery because they are not suitable for planting and you should have taken this into consideration in planning the annual production (see Section 4.1).

Sort the plants out so that only those suitable for planting, and with a good chance of survival, are used. Cull thoroughly, following a previously planned specification that includes size, health, no distorted growth and lack of any damage. Keep the specification easy to apply. This should make it much easier to introduce the idea to naikes who are unfamiliar with it and may be reluctant to throw apparently sound plants away. Reject all plants that do not meet the specification.

Destroy all shrubs and trees that are not of a good enough standard to be used on site. Do not keep them for next year in the hope that they will be better.

Preparing and packing grass slips for transport

Lift grass clumps carefully, keeping the root ball intact so that the roots are not damaged. Wrap the root ball in wet hessian. Split them out on site. Trim the roots and stems to length, as for nursery planting. Wrap bundles of slips in wet hessian until they are needed for planting by the site labourers. Do not let them get exposed to direct sun because this will dry out the grass slips rapidly. At every stage, encourage labourers to treat the grasses as if they are slips of millet or rice, which are being transplanted.

Preparing and packing polypots for transport

Thoroughly water plants in polypots 2 to 3 days before they are to be transported and, again, lightly water them the evening before planting. Soil that is too wet or too dry tends to break up and this can damage plant roots. Thorough watering in advance is very important because it helps the plant withstand dry periods immediately after planting (one of the major advantages of using polypot plants).

Handle the plants by the container, not by their shoots; the stress caused by the transfer from nursery to plantation is great enough, without adding to it unnecessarily. When you are handling and transporting seedlings, ensure that the soil around the roots is not broken or damaged. Pack them vertically and close together so that they cannot shake about or fall over during transport. However, in packing them closely together do not force them as this will also break the soil cone and damage the roots.

If possible, transport the polypots in trays made of metal or wood. A 400 × 250 mm tray, with sides 100 - 120 mm high, containing about twenty-four 4" × 7" polypots, weighs about 12 kg and can be safely handled by one person. Paint numbers on the trays to make it easy to keep track of them and ensure they all come back to the nursery.

Although not ideal, you can also use dokos for carrying plants. Fill the bottom of the doko with straw or some other light material to form a firm level base for the plants to stand on. Pack the seedlings so that they are vertical and will not shake about. About 40 plants in 4" × 7" polypots can be transported at a time. This makes a normal load of 20 to 25 kg. Place the plants into the doko individually. Never allow the pots to be bundled together and tied with string. It breaks the soil root ball and damages the roots of all the plants on the outside of the bundle.

Preparing and packing other plants for transport

Stumps are easy to transport; which is their major advantage. Wrap them in wet jute cloth, tie the bundles with string and keep them in a cool shady place. Do not let them dry out.

Dig up bare-root plants carefully, shake the soil off their roots, cull and then make up bundles of 100 to 300 with only the roots wrapped in saturated jute cloth. Do this work quickly and in the shade. Bare-root seedlings can also be transported in plastic buckets with their roots submerged in a mixture of 1 kg clay in 1 litre of water.

Never take more planting stock to site than can be planted that day. With a bit of experience staff can judge the requirements and ensure that surplus stock is not kept on site overnight.

Care of planting stock on site

Once the nursery stock is on site, treat it carefully. There will often be a delay before it is planted. Plants treated carelessly can be badly damaged on site and this can make the entire bio-engineering programme useless.

Keep bare-rooted plants and slips in damp hessian. Do not stack them in damp bundles in big heaps, as they will soon start to rot. Assign one person to the task of repeatedly checking the plants and ensuring that they are in good condition. This person can move them as necessary and add water when they start to become dry.

Ensure that all labourers know that they must lift polypot seedlings by the pots, not by the stems. They should be moved in strong trays or a few at a time in the hands.

Always handle plants, slips and cuttings carefully. Always keep them moist and in the shade, and never let them dry out. Destroy plants that have dried out, as they are certain to die.

Use of registers

There are four registers used in bio-engineering nurseries. They are all given in Annex C.

· Grass slip hardwood cutting register.
· Seedling register.
· Seed identification register.
· Seed collection calendar.

The purpose of each of these is described below.

Grass slip/hardwood cutting register

This provides a simple method of keeping track of grass and cutting stocks in a nursery. It allows the Overseer and Engineer to check on the amounts of material available when calculating site requirements. It also permits checking of likely problem areas if plants fail on site.

Seedling register

This does the same for plants produced from seed in the nursery. Their progress is checked from the time of germination onwards. It allows monitoring of technical problems in plant production, since it will be clear if the seedlings have fared particularly badly at any stage of development.

Seed identification register

It is important that seeds are kept in good condition and that they do not stay too long in the nursery. This register provides the information required to track problems resulting from poor germination, and to ensure that seed sources are of adequate quality.

Seed collection calendar

This is not a formal register. Instead, it serves to remind staff of the seeds that must be collected to provide future plants in the nursery. It has to be filled out locally, since it depends both on the particular bio-engineering programme and the availability of seeds in the area. It lists, month by month, the seeds that must be collected and the places from which they can be taken.

Making and using compost

Compost is produced from the breakdown of organic materials by micro-organisms in a warm, moist, aerated environment. The bacteria responsible for this require moisture, oxygen, carbon, nitrogen, and other nutrients. The energy they use is given off as heat.

Compost is added to the beds in nurseries to enrich the soil and help to retain moisture.

Good compost is black and crumbly, and you cannot distinguish the original plant parts. If standard farm 'mull' is used, you must check that it is in this condition, which means that it has decomposed fully.

You can make compost out of almost any organic material that is easily available. This includes weeds, forest litter, crop residues, animal bedding and dung. Weeds such as ban mara are plentiful during the monsoon, which is the best time to start compost making. Crop residues and pine needles take much longer to compost than recent weed growth and litter from the forest floor because they contain too much carbon and not enough nitrogen. When you compost them you can speed up the process by adding liquid manure and larger amounts of recent weed growth. Chop up large material such as maize straw before you compost it.

You can make compost in a compost bay, a simple heap or a pit. Compost bays or heaps are best because pits are easily water-logged in the monsoon. Make the volume between 1 cu. m and 4 cu. m with a maximum height of 1.5 to 2.0 metres. In order to ensure good aeration, start with a layer of brushwood, old branches or rocks. Then pile the compost materials on top, ensuring that there is a good mix of different sizes and types. Apply components that are in short supply, such as farmyard manure, animal bedding and liquid manure (1 part dung mixed with 10 parts water), in thin layers every 200 - 300 mm. Add layers of a good loamy soil every 200 - 300 mm. If the components are dry before starting the heap, wet them for a few days beforehand. Layers of lime at a rate of 0.5 kg/cu. m will help promote the decomposition of acid components such as pine needles.

When the heap is finished, cover it with a large polythene sheet. This will prevent the compost from getting too wet, will conserve heat and, after the monsoon, will prevent it drying out. Two to four weeks later the heap should have heated up to its maximum and will need turning. Check the temperature by pushing a thin metal rod into the middle of the heap; if it becomes too hot to touch, the heap is ready to be turned. Simply dig it up and make a new one alongside it. This serves to aerate the components and to mix in the outer parts of the heap, which do not heat up as much as the inside. Inspect the heap occasionally to ensure that decomposition is taking place. You can find information on poor decomposition in the Reference Manual.

Compost making may take only 2 - 3 months in the Terai but may take more than 6 months above 2,000 metres. Other factors, however, are more important than altitude, in particular the attention paid to correct techniques, and the type of material used.

When the compost has been made, pass it through a soil sieve before mixing it into beds or potting mixtures. The larger components, which will not pass through the sieve, can be used for starting up another heap, as they will introduce bacteria to it. Add compost to every bed at least once per year. This is best done when the bed is empty and about to be cultivated. Make sure it is mixed well with the soil.

About 20 dokos (70 litres) of fresh green vegetation, such as ban mara, each weighing 20 - 30 kg with the material piled up above the rim of the doko, are needed to make one doko of compost, weighing 35 kg with the compost level with the rim.

Figure 4.11 Nursery troubleshooting chart

PROBLEM

DIAGNOSIS

ACTION IF "YES"

ACTION IF "NO"

SEEDS




Seeds not germinating

Has the weather been cold?

Wait for warmer weather and check again Alternatively place cloches over the beds and monitor carefully.

Consider other possibilities.


Is the bed waterlogged?

Allow the bed to dry until it is just slightly moist check the seeds are not rotten be very careful not to over water.

Consider other possibilities.


Are the seeds rotten?

Remove the seeds from the seed beds replace the top layer of soil/sand re sow the seeds be very careful not to over water Remove cloches if they have been used.

Consider other possibilities.


Do the seeds seem healthy?

The seed may no longer be viable Obtain new seeds and re sow.

The seed may have been stored badly Obtain new seeds and re sow.

GRASSES




Grasses are growing
abnormally slowly

Has the weather been cool or lacking in sun?

Wait for warmer weather and check again Alternatively place cloches over the beds and monitor carefully.

Consider other possibilities.


Is the soil in the beds mostly dry?

Increase the rate of watering.

The soil in the beds may be poor If there are still several months before site planting transplant to a new bed with better soil If there is little time add fertiliser.

Grasses are very yellow

Is the soil in the beds very wet?

Reduce the fate of watering.

Add a nitrogen based fertiliser.

SHRUBS AND TREES




Poor growth

Has the weather been cool or lacking in sun?

Watt for warmer weather and check again.

Consider other possibilities.


Does the soil in the polypots feel hard?

The pots may have been over compacted when filled or there may be too much clay in the potting mixture Loosen the soil with a pointed stick taking care not to damage the plant roots and water regularly.

Consider other possibilities.


Is the soil in the polypots mostly dry?

Increase the rate of watering.

The potting mixture may be poor If the plant is small transplant it to a new pot with a better mixture If it is big water dilute fertiliser on to the plants using a watering can.

Plants become long and thin

Are the plants kept under shade?

Reduce or remove the shades.

Increase the spacing between the plants.

Plants have yellow leaves

Is the soil in the polypots very wet?

Reduce the rate of watering.

Add a nitrogen based fertiliser.

Plants have wilting leaves

Is the soil in the polypots dry?

Increase the rate of watering.

Consider other possibilities.


Have the roots just been pruned?

Wait a week and check again.

Consider other possibilities.


Have there been gusty winds recently?

Wait a week and check again.

Consider other possibilities.


Are there signs of attack by insects or fungus?

Spray with the most appropriate insecticide.

The potting mixture may be poor If the plant is small transplant it to a new pot with a better mixture If it is big add fertiliser.

Small plants suddenly
start to die off

Does it look like damping off described in Section 4.6 (p104)?

Reduce watering and shading.

Consider other possibilities.


Is there evidence of other fungal attacks (white hairs growing on the plants)?

Reduce watering and shading.

Consider other possibilities.


Is the soil very wet?

Reduce watering.

Consider other possibilities.


Do the plants look rotten?

There may not have been enough ventilation leading to excessive humidity on hot days Ensure that air can flow under the sides of the shades Remove the shades more.

Look for signs of insect damage to the roots and treat the plants accordingly.

Excessive growth

Are roots growing into the ground below the bed?

Prune the roots level with the bottom of the pots.

Reduce the amount of water and increase the amount of shade.

BAMBOOS




More than 25 percent
of cuttings fail to grow

Is the soil moist and shady all the time?

Look at other possibilities.

Increase the amounts of water and shade.


Are there signs of insects especially termites attacking the cuttings?

Re plant with new cuttings flood the beds again and check carefully every day for the next week If the termites or other insects persist excavate the cuttings carefully and sprinkle Aldrin dust around the cutting Reduce the watering and observe carefully over the next week If all is well then increase the watering again.
Take care: Aldrin is highly poisonous.

The nutrient status of the bed may be poor Improve the depth and quality of soil in the bed and re plant the failures.

Poor growth

Is the soil deep and stone free?

The nutrient status of the bed may be poor Add fertiliser.

Improve the depth and quality of soil in
the bed and re plant the cuttings.

Troubleshooting

All nurseries, however well run, experience difficulties at some stage. To assist in detecting problems, a troubleshooting chart is given in Figure 4.11. While this covers the most common problems, always bear in mind that there are exceptional circumstances. If you cannot resolve a problem, call the Geo Environmental Unit for specialist advice.

4.7 Seed collection, treatment and storage

Seed collection, treatment and storage are a skilled business. Care has to be taken in order to ensure that you get material of good quality as a basis for a bio-engineering programme.

Seed collection: basic considerations

Start by choosing carefully the location and actual plants from which you collect seeds.

· Collect seeds from plants growing in sites similar to the ones you are going to plant the seedlings on.

· Collect seeds from plants with the characteristics you want (e.g. good rooting): seedlings grow like their parents.

· All seed plants should be healthy and growing vigorously.

· Always collect seed from at least 10 plants, to increase the genetic diversity.

If you have to order seed from elsewhere, give as many details as possible about the planting site (altitude, rainfall, soil) and also how many seedlings will be needed. Ask the supplier to match these considerations as closely as possible.

Keep a register of all sources of seed within your working area, with details of the species, area of the stand (or number of plants), and location. This register will help you plan seed collections. A form for this is given in Annex C.

Keep seed from very different sources separate, i.e. sources that are several kilometres apart. Never mix new collections with seed from previous years. Label every seed lot properly with species name, date of collection, location, and the number of seed plants.

Calculating how much seed to collect

Because of natural uncertainties, you need to obtain and sow many more seeds than the actual number of seedlings required. If the seed collectors manage to collect more seed than is needed, do not waste it by sowing too much in the nursery, or storing it carelessly. Seed supplies are always difficult and there may be other nurseries that could use it. Tell the Geo-Environmental Unit, the Regional Director's Office, and other Divisions and Projects. Someone else may well be able to use it.

Calculation of grass seed requirements

It is normal in bio-engineering to sow grass seeds at the rate of 25 g per sq. m. This covers all expected natural losses. However, in case the first seeding fails, it is normal to ensure adequate supplies for a separate complete seeding. Therefore aim to collect seed according to this equation:

Seed required (kg) = area to be seeded (sq. m)/20.

Calculation of shrub and tree seed requirements

It is normal practice to grow 25 per cent extra seedlings and discard the poorer plants when they leave the nursery. It is also normal to allow four times the amount of seed for the total number of seedlings to be grown. Therefore, for every one seedling to be used on site, five seeds should be obtained and sown.

Figure 4.12 shows as an example the quantity of seeds required to grow 5,000 each of utis and khote salla trees.

The tables in Annex B give the average numbers of seeds per kilogramme for all the bio-engineering species. Once you know the number of seeds required, you can easily calculate the weight of dry seeds to be collected.

Collecting and treating grass seeds

In bio-engineering it is normal to collect and use the whole seed head of grasses. The procedure is as follows:

· Collect the seed heads when they are ripe. Bring them back to the camp or nursery in dokos or hessian sacks. If you use polythene bags, empty them out as soon as possible so that they do not go mouldy.

· Spread the seed heads out to dry in sheltered, sunny places, on a clean concrete or hard earth floor.

· Separate them from stems and other unwanted parts in the ways normally used for grains. Since the seeds of bio-engineering grasses are mostly very fine, take great care when winnowing.

· Store them in hessian or polythene bags in a dry, well ventilated place. If you use polythene bags, make sure that the heads are completely dry or they will go mouldy.

· Most grass seeds will remain viable1 for several years, but you should use them within one year if possible.

1 Viability is the length of time that the majority of seeds remain able to germinate. After a certain period of storage, seeds will not germinate once sown. This varies for each species, and approximate viability periods are given in the tables in Annex B.

Collecting shrub and tree seeds

Tree climbing

Climbing trees to collect seeds is dangerous and must be done carefully, so as to avoid accidents. Falling from trees is a common accident and your collectors should be especially cautious while collecting seeds. Local methods can be safe if properly supervised. Follow these guidelines for safety:

· only employ seed collectors if they like climbing;
· only use strong and healthy collectors;
· collectors should work in twos; then if one needs help, the other can go and get it;
· only healthy trees with strong branches should be climbed;
· while picking fruits, the climber should be tied to the tree whenever possible;
· proper fruit cutting tools with long handles (see below) should be used, so that there is no need to cut off large branches.

If seed must be collected from very large trees that are dangerous or difficult to climb by local methods, contact the Geo-Environmental Unit or the local Department of Forests office for advice. Special equipment (spurs, safety belts and ropes) and trained seed collectors may be available. It may be useful for someone in your area to receive such equipment and training, which is sometimes given by the Department of Forests.

What fruits to harvest

Collect only ripe fruits. If fruits are collected too early, the seed may be immature and weak. If you delay collection too long, the seed may be eaten by birds, or attacked by insects or fungi. Pick fleshy fruits just as they turn from green to their ripe colour. Pick dry fruits that open just before they open. Test the ripeness of seed by cutting the fruit open and looking at the inside of the seeds. They should be firm and white, and completely fill the seed coat. The seed coat should usually be dark and hard.

Do not collect fruits that are unhealthy or attacked by insects. For this reason avoid fruits that have fallen to the ground.

How to harvest the fruits

Harvest the fruits without damaging the tree, so that it can produce again in the following years. Whenever possible, take only the fruits or the small twigs bearing them. Try not to tear them off, but cut or break them cleanly. Unless it is absolutely necessary, do not allow seed collectors to cut whole branches with a khukuri or hasiya.

Good seed-collection tools include:

· A hook for bending branches towards the collector. Fix a metal hook to a wooden handle 2 m long. Provide a 2 m length of rope so that the climber can tie the hook and the branch to himself, so that he has both hands free to pick the fruits and put them in the collecting bag, A strongly made hook can also help in climbing the tree.

· If it is necessary to break off the ends of branches with the fruits attached, a 'wedge knife' will work well. This can be made in any large bazaar. It should be bolted or tied with wire to a light, long wooden or bamboo pole (up to 4 m). The collector places the tool over the branch end and pulls it. The branch may slice off easily, but if it is woody, the knife may have to be twisted to snap the branch.

· A collecting bag can be made from a strong hessian sack, which has been made shorter and has a draw string to close the mouth easily. When full, the bag is closed and thrown to the ground.

Figure 4.12: Example of tree seed calculations

S No

DETAIL

UTIS

KHOTE SALLA

[1]

Number of plants needed

5,000

5,000

[2]

Number of plants to be produced: [1 ] × 1.25

6,250

6,250

[3]

Number of seeds needed: [2] × 4

25,000

25,000

[4]

Seeds/kg

1,350,000

10,000

[5]

Seeds/g

1,350

10

[61

Grammes of seed required: [3] / [5]

18.5

2,500

[7]

Seed order

20 g

2.5 kg


Wait for seed to ripen properly before picking it from the tree

The best material for long handles is one-inch aluminium tube with thick walls, which can be purchased in large bazaars. Otherwise, use well dried wooden or bamboo poles.

If it is difficult to gather the fruits by hand in the tree, they can be allowed to fall to the ground and be gathered by an assistant. Clearing the ground of vegetation may help. The assistant should wear a strong hat as protection from falling fruit and twigs. It is safer to wait until the climber has finished his work.

Transport and storage of fruits

Store and transport fruits in cloth or hessian sacks. Do not put them in polythene bags, as they will get warm and mouldy very quickly, spoiling the seeds inside. Always store the sacks in the shade. Keep them cool, dry and off the ground by placing them on planks of wood, or by hanging them.

When to collect seeds

You need to know the dates for seed collection in order to get good results. Details are given in the tables in Annex B, as far as they are known, for all of the bio-engineering species. Remember that these give an approximate guide only, and there is always some local variation. Every month, you should check which species are due to ripen, so that you do not forget to arrange for their collection.

As part of the routine planning of a bio-engineering programme, you should establish a seed collection calendar for your Division or Project. A form for this purpose is given in Annex C.

Before the collecting season of a species starts, the person responsible should keep a regular check on how the fruits are ripening. In some years, fruits will ripen earlier than usual, and in other years they may ripen later. As a general rule, fruits tend to ripen later in the west than in the east, and are also later at higher altitudes.

Processing and storing shrub and tree seeds

Seed processing following collection

Most seeds need to be removed from their fruits before sowing or storage. Separate them carefully to avoid damaging the seeds. Although they may look inert and tough, heat, moisture, physical breakage, fungi, insects, etc can easily damage them. Try to extract the seeds as soon as possible after collection, unless recommended otherwise.

The pods of many leguminous species (e.g. sisau, khayer, areri and the siris species) are brittle and split easily once they have been dried in the sun. The seeds must be carefully separated from all the pod fragments that result.

Some species (e.g. bakaino) have a stone inside a fleshy fruit. The flesh must be removed before storage. This is best done by soaking in water and then rubbing the soft fruits together so that the flesh comes away. Once cleaned, the seeds must be properly dried in the sun.

Fleshy fruits containing many small seeds (e.g. khanyu) are separated in the same way, but much more care has to be taken because the seeds are much smaller and more delicate. Again, once cleaned, the seeds must be properly dried in the sun.

Storing seed

If you are sowing the seeds immediately after processing (within a few days), put them in a cloth bag and keep them cool. Never use a sealed container such as a polythene bag, glass jar or tin, as the seed will be too moist and will quickly get warm and mouldy.

If you are keeping the seeds for more than a week (often several months or even a year may be required), store them properly to avoid loss of viability. When the seeds have dried sufficiently, leave them in the sun until the afternoon, and then put them immediately into a container that can be properly sealed, thus keeping them dry. Do not leave packing until the morning, as the seeds will absorb moisture overnight.

The simplest container is a thick polythene bag, or two thin ones, one inside the other. Squeeze out the excess air, and then tie the neck tightly with string or wire. It is often a good idea to put the bag in a tin box to protect it from being punctured and from rodents that may try to eat the seed. Label and number the containers of seed.

Keep the containers in a cool, dry room. The best place is a well-ventilated ground-floor room on the north side of a two-storey building. Keep the containers off the ground, preferably on shelves half way up the wall. Do not put them in the eaves of a roof, as this will become warm during the day; or directly on a ground floor as this may be damp.

Recalcitrant seeds

Most seeds have to be dried before storage and are called 'orthodox'. But some species have seeds that must be kept moist if they are to remain viable. They are called 'recalcitrant'. If they are dried they will quickly die. These seeds are often found in species that have fleshy fruits which do not dry out on the tree, and which are dispersed just before or during the rains. The species used for bio-engineering which fall into this category are badahar (Artocarpus lakoocha), champ (Michelia champaca), chiuri (Aesandra butyracea), dhale katus (Castanopsis indica), chuletro (Brassaiopsis hainla), khasru (Quercus semecarpifolia), kutmero (Litsea monopetala), musure katus (Castanopsis tribuloides), okhar (Juglans regia), patle katus (Castanopsis hystrix) and phalant (Quercus lamellosa).

Always sow this type of seed as soon as possible. If it has to be stored for more than a week, use the following method. Extract the seed from the flesh, do not dry it, but mix it with twice its volume of damp sand. Put this mixture in a tin with a lid, whose sides and bottom have at least 20 small holes (2 mm diameter), made with a nail. After putting in the sand/seed mixture, fill it to the top with damp sand. Dig a hole 1 m deep in a sheltered and well-drained place. Cover the bottom with a layer of damp sand, and put the seed containers on it. Then cover with more damp sand, and fill the rest of the hole with the excavated soil. Mark the spot with a stick. When you require the seed, dig it out. Remove the seed from the sand carefully, as some of it may have started to germinate.


Dry seeds thoroughly before storing them in a container that can be properly sealed

4.8 Assessing the quality of bio-engineering nurseries

The following are some simple indicators for assessing the quality of bio-engineering nurseries. They are not comprehensive.

Grass beds (slip and rhizome cuttings, and grass seeds) and hardwood cutting beds should be:

· composed of good, fertile, well aerated soil;
· kept moist at all times;
· showing even growth;
· well weeded;
· kept with a porous, uncapped soil surface.

Grass plants should be:

· a healthy green colour;
· growing vigorously, with long new shoots;
· showing no signs of wilting;
· attack.

Shrub and tree seed beds should be:

· composed of good, fertile, well-aerated soil and fine, clean sand;
· kept moist at all times;
· well shaded;
· showing even growth;
· well weeded.

Polypot seedlings should be:

· a bright, healthy colour;
· showing no signs of wilting;
· growing fast, with long new shoots;
· kept with roots pruned; kept moist throughout the soil cylinder;
· well weeded;
· without signs of discoloration on the leaves;
· without signs of insect attack on the leaves or shoots (e.g. holes eaten in the leaves);
· without any obvious signs of disease;
· undamaged.

Whole nurseries should be:

· kept tidy and clean;
· weeded throughout;
· well maintained;
· protected properly at all times.

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