Go to start
Go to start Pig Feed Improvement through Enhanced Use of Sweet Potato Roots and Vines in Northern and Central Vietnam
Contents:
INTRODUCTION
PART I -SELECTING AND GROWING SWEET POTATO FOR LIVESTOCK
1 Technology for growing dual-purpose and forage-purpose sweetpotato in the Northern Midlands of Vietnam
2 Technology for growing dual-purpose and forage-purpose sweetpotato in the Red River Delta of Vietnam
3 Technology for growing dual-purpose and forage-purpose sweetpotato in North-Central Vietnam
PART II - SWEETPOTATO ROOT AND VINE PROCESSING AND FEEDING TO PIGS
1 Sweetpotato vine and root ensiling methods and use of silage as pig feed
2 Feed crops and their processing and storage methods
3 Composition of concentrate feed mixtures (basal feed) and the rations for pigs for various weight categories
Technical supplement: Some principles of pig nutrition in the tropics

2 Technology for growing dual-purpose and forage-purpose sweetpotato in the Red River Delta of Vietnam

2.1 Characteristics of the Red River Delta

2.1.1 Soils

The Red River Delta was deposited by the Red River and the Thai Binh River, resulting in fertile alluvial soils. Total land area of the Red River Delta is 1,250,000 ha., of which Agricultural land occupies 721,321 ha. (57%). Of the total agricultural land, 643,021 ha is cultivated annually, leaving only 11% to fallow. Rice cultivation, as the most important crop, occupies 91% of annual crop land area.

2.1.2 Climatic conditions

The Red River Delta has a monsoon climate. The average temperature between November and April is 15-18°C, with the coldest months in January and February, when it can drop to as low as 5-9°C. There are two distinct seasons a year: dry season from November to April and rainy season from May to October. The average rainfall is 1,800-2,000 mm, mainly concentrated during the rainy season, when it usually storms and floods the delta between July and October.

2.1.3 Population and density

The small area of the Red River Delta boasts a big population of 14,800,100, with the majority (78.9 %) residing in rural areas. Due to the high population density, agricultural land per capita averages only 553 m2. The Kinh people comprise the majority of the population in the area.

2.1.4 Crops and production systems

Sweetpotato is planted in winter between two rice crops to serve a feed source for animal production in fresh and processed form. The agriculture rotation systems are as below.

- On secondary land:

Winter/Spring sweetpotato - Sesame - Autumn/Winter sweetpotato
Spring groundnut - Sesame - Autumn/Winter sweetpotato
Winter/Spring sweetpotato - Sesame - Autumn groundnut

- One rice crop with two secondary crops:

Winter/Spring sweetpotato - Main winter rice
Spring sweetpotato - Early winter rice - Potato
Spring sweetpotato - Early winter rice - Winter sweetpotato
Spring groundnut - Early winter rice - Winter sweetpotato
Winter sweetpotato - Winter rice seedling - Late winter rice

- Two rice crops with a winter crop:

Late spring rice - Early winter rice - Winter sweetpotato

2.2 Geographical location

The Red River Delta of Vietnam consists of the following provinces: Hai Phong, Hai Duong, Hung Yen, Ha Tay, Ha Noi, Nam Dinh, Ha Nam, Thai Binh and Ninh Binh. The following recommendations also apply to some neighbouring provinces that share similar topographical and soil characteristics.

2.3 Recommended sweetpotato varieties suitable for root and vine dual-purpose and their characteristics.


2.3.1 The characteristics of yield, agronomic performance, and growing period

Distinguishing characteristics

Varieties

 

Hoang long

Nr.8

KL5

KL6

KB1

Root yield (ton/ha)

16-18

18-20

22-27

24-28

16-30

Vine yield (ton/ha)

17-20

18-20

20-25

21-25

18-20

Root DM yield (ton/ha)

4.59

5.65

6.25

6.35

6.46

Root starch yield (ton/ha)

3.93

4.84

5.25

5.18

5.34

Season suited to planting

Winter

Winter, spring

Winter, spring

Winter, spring

Winter, spring

Tolerance performance:

 

 

 

 

 

  • Drought tolerance

Fair

Fair

Good

Fair

Fair

  • Submergence tolerance

Poor

Poor

Poor

Poor

Poor

  • Cold tolerance

Medium

Fair

Good

Fair

Fair

  • Leaf insect tolerance

Fair

Fair

Fair

Fair

Fair

  • Weevil tolerance

Medium

Fair

Fair

Fair

Fair

Growing time (days)

100-120

100-120

100-120

100-120

100-120


2.3.2 The characteristics of utilization, vine, root and storage

Distinguishing characteristics

Varieties

 

Hoang long

Nr.8

KL5

KL6

KB1

Root palatability:

 

 

 

 

 

For humans (boiled)

High DM

High DM

High DM

Med. DM

High DM

For pigs (cooked)

Good

Good

Good

Good

Good

Vine palatability:

 

 

 

 

 

For humans (boiled)

Bitter

Med. sweet

Sweet

Sweet

Med. sweet

For pigs (fresh)

Bitter
(Should be cooked)

Med. sweet
(Should be cooked)

Sweet

Sweet

Med. sweet

Method of storage:

 

 

 

 

 

Time (month)

3

3-4

3-4

3-4

3-4

Way to store

Dried

Dried

Dried

Dried

Dried

Roof morphology

 

 

 

 

 

Color of skin

Light red

Red-Pink

Red-Pink

Red

White

Color of root flesh

Yellow

Ivory white

Ivory white

Ivory white

Ivory

Shape of root

Slender

Slender

Slender

Slender

Slender

 


2.4 Sweetpotato varieties suitable for forage purpose and their characteristics

2.4.1 The characteristics of yield, agronomic performance, and growing period

Distinguishing characteristics

Varieties

 

Hoanglong

Nr.8

KL1

KL5

KL6

Fresh vine yield (ton/ha)

17-20

18-20

20-25

20-25

21-25

Fresh leaf yield (ton/ha)

11.75

12.50

14.25

13.50

13.25

Leaf DM yield (ton/ha)

2.30

3.25

3.80

3.90

3.01

Leaf CP yield (ton/ha)

0.34

0.49

0.54

0.58

0.48

Season suited for planting

Winter

Winter, spring

Winter, spring

Winter, spring

Winter, spring

Tolerance performance:

 

 

 

 

 

Drought tolerance

Fair

Fair

Fair

Fair

Fair

Submergence tolerance

Poor

Poor

Poor

Poor

Poor

Cold tolerance

Medium

Fair

Fair

Fair

Fair

Leaf insect tolerance

Fair

Fair

Fair

Fair

Fair

Weevil tolerance

Medium

Fair

Fair

Fair

Fair

Branching

Strong

Strong

Strong

Strong

Strong

Re-growing

Fair

Fair

Fair

Fast

Fair

 


2.4.2 The characteristics of utilization, vine, root and storage

Distinguishing characteristics

Varieties

 

Hoang long

Nr.8

KL1

KL5

KL6

Vine palatability:

 

 

 

 

 

For humans (boiled)

Strong, a bit sweet

Med. sweet

Med. sweet

Sweet

Sweet

For pigs (fresh)

Strong, a bit sweet
(Should be cooked)

Med. sweet

Med. sweet

Sweet

Sweet

Method of storage:

 

 

 

 

 

Time (month)

3-4

3-4

3-4

3-4

3-4

Way to store

Dried

Dried

Dried

Dried

Dried

Vine morphology:

 

 

 

 

 

Shape of leaf

Heart shape

Dentate

Heart shape

Dentate

Elliptical

Color of tender leaf

Purple

Light green

Light green

Light green

Light green

Color of adult leaf

Green

Green

Green

Green

Green

Color of stem

Violet

Purple green

Green

Green

Green


2.5 Technologies that can be applied to increase vine and root yield

2.5.1 Selecting the appropriate variety

USE purpose

Spring crop

Winter crop

Dual purpose

Nr.8,KB1,KL5,KL6

Nr.8,KB1,KL5,KL6,Hoanglong

Forage purpose

Nr.8,KL1,KL5,KL6

Nr.8,KL1,KL5,KL6,Hoanglong

2.5.2 Planting season

 

Spring crop

Winter crop

Planting season

10 February-25 February

25 September-25 October

Favorable conditions


Unfavorable conditions

  • From planting to harvesting the temperature and moisture are fairly suitable for growing sweetpotato.
  • Need to avoid plants submerged in water and over-producing vines at the end of the season
  • At the start of winter high mois­ ture and temperature create good conditions for vine growth.
  • At the end of the dry season low temperature and moisture prevent good root development.

2.5.3 Soil characteristics

 

Spring crop

Winter crop

Proper soil type

Mixed sandy, light loamy, riverside, gar­ den, along canals and dikes

Mixed sandy, light loamy, riverside, garden, along canal and dikes

Land type

High land, upland, well drained

High land, upland, and middleland

2.5.4 Soil preparation

 

Spring crop

Winter crop

Requests and ways

Plough deep to prepare beds

Plough deep to prepare beds

Size of beds

1.1 -1.2m wide, 0.4-0.45m high

1.1 -1.2m wide, 0.4-0.45m high

Distance between beds

10-30 cm

10-30 cm

Direction of beds

East-West

East-West

 


2.5.5 Planting method

 

Spring or winter crops

Vegetative multiplication

Cut 1st and 2nd sections for multiplication purpose. Plant in distance of 15x20 cm.

Multiplication method of planting material from root

Choose standard breeding roots and keep in the house. The shoots can be planted as planting material. Plant in density of 5-7 roots/m 2.

Preparation before cutting planting material

At least 45 days after multiplication, vines can be cut for planting.

Standards of good planting material

The 1st and 2nd section of an adult stem.

Method of cutting planting material

Depends on characteristics of the variety (selec­tive cutting of vines from certain plants of each bed).

Length of stem (cm)

25-35

Number of nodes/stem

5-7

Planting method

One row in the middle of the bed

Density (stem/m of bed)

4-5


2.5.6 Fertilization

 

Spring or winter crop

Ratio and total amount of fertilizers (kg/sao)

300 - 500 kg manure
4 - 5 kg urea (N)
12 - 15 kg Super phosphate (P)
4 kg potassium chloride (K)

Basic fertilization

Mix manure with P, put in the furrow and cover with soil from the bed. Then, top it off with 1 kg of urea.

First additional fertilization

  • Timing
  • Amount (kg/sao)
  • At 25 - 30 days after planting
  • 2-3 kg urea mixed with 3 kg potassium chloride

Second additional fertilization

  • Timing
  • Amount (kg/sao)
  • At 2-3 days after pruning the stems
  • 0.5-1 kg urea


2.5.7 Cultivation technology

 

Spring crop

Winter crop

Pinching off young shoots

At 25-30 days after planting (several days before or after the 1 st additional fertilization) cut the tops to help branching and optimise vegetative development.

At 25 days after planting (several days before or after the 1 st additional fertilization) cut the tops to help branching and optimise vegetative development.

Re-mounding the bed for weed control

At 25-30 days after planting, hoe deeply into soil, turn up the bed slightly linking this activity with the 1 st additional fertilization. At 10-1 5 days after the 1 st addi­ tional fertilization, hoe, turn up soil slightly.

At 25 days after planting, hoe soil deeply, turn and earth up the bed slightly, in combination with the 1 st additional fertilization. At 10-15 days after the 1 st addi­ tional fertilization, hoe, turn slightly and earth up the bed highly.

Irrigation

Keep soil moist for 2-3 days after planting so that the stems can re- grow.
Irrigate 2-3 days after turning up the bed and 1 st additional fertiliza­ tion application.
At 45-50 days after planting if too much vine during the first period, some stems should be cut and stems should be lifted to break excessive roots.

Keep soils moist for 2-3 days after planting so that the stems can re- grow.
Irrigate, flood 1/2-1/3 of the furrows, keep soil moist when weather is dry.
At 45-50 days after planting if too much vine during the first period, some stems should be cut and stems should be lifted to break


2.5.8 The vine-cutting method for forage varieties

 

Spring crop

Winter crop

First vine harvest

 

 

  • Time to start harvest
  • Harvesting criteria
  • At 40-45 days after planting
  • Cut 1/3-1/4 of the length of the longest vine
  • At 40-45 days after planting
  • Cut 1/3-1/4 of the length of the longest vine

Subsequent vine harvests

Every 7-10 days after the first harvest depending on the rains.

Every 10 days after the first harvest depending on the rains.

 

Cut 1/3-1/4 of the length of the longest vine.

Cut 1/3-1/4 of the length of the longest vine.

 

Nitrogen should be added after each cutting (0.5 - 1.0 kg urea / sao).

Nitrogen should be added after each cutting (0.5 - 1.0 kg urea / sao).

 

Cut stems every 10-15 days until the last harvest.

Cut stems every 10-15 days until the last harvest.

 

Depending on vegetative growth, cut 2-3 longest stems, up to 4 stems if much growth, leaving 15-20 cm. More stems can be cut near the end harvest

Cut 2-3 longest stems of a plant, leaving 15-20 cm. Irrigate while applying additional fertilizer after cutting.

 


2.5.9 Main insects and protection

 

Spring or winter crop

Weevil

Use traps (For example: chopped sweetpotato pieces) to lure adult weevils to come to lay eggs, then get the traps to kill larvae. Mound high beds and keep soil moist to reduce weevil damage. Use biological control such as introduction of natural enemies, manipula­tion of habitat, conservation of natural enemies through avoidance of pesticide use or trap weevils to eliminate them.

Sweetpotato Hornworm (Agnus convolvuli)

Sweetpotato rotating with paddy rice helps eliminate insects. Leaf-eating caterpillar can be caught by hand.

Scrap

Planting tolerant varieties is the best protection from scrap. Check and eliminate the attacked plants

Black rot

Restrict irrigation during the final period. Rotate sweetpotato with other crops in paddy fields, or plant on highlands.

2.5.10 Harvest

 

Spring crop

Winter crop

Root harvest

Time to harvest

120 days after planting

100 days after planting

Day to harvest

Dry and sunny days

Dry and sunny days

Methods to harvest

Plough with buffalo or hoe. Avoid damaging roots

Plough with buffalo or hoe. Avoid damaging roots

Vine harvesting

Time to harvest

Start to harvest vine for animal feed at 45-50 days after planting

Start to harvest vine for animal feed at 45-50 days after planting

Day to harvest

Every 7-1 0 days after the first vine harvesting

Every 7-10 days after the first vine harvesting

 


2.5.11 Storage

 

Spring or winter crop

Storage of roots

Methods to store roots

Clean soil or sand from roots, keep in dry, airy, and cool places

Some remarks during storage

Check regularly to eliminate rotting roots

Storage of vine

Methods to store vine

Drying or ensiling

Storage duration

3-4 months

Some remarks during storage

After 14 days ensiled feed can be fed to pigs. It can be stored for at least 4-5 months. It has the typical smell and taste of ensiled feed. Check the bags regularly to make sure of anaerobic condition to avoid rotting and molding.

 


2.5.12 Recommended utilization

 

Spring or winter crop

Vine

The soft and sweet vine can be used as vegetable for humans or forage for animals

Root

Roots can be boiled or dried for human consumption or animal feed

 


Previous
Next