· Air must circulate in the soil.
The microbes, which are living things, need air to
To live, they decompose the organic matter in the soil.
If there is no air, the microbes cannot breathe.
They cannot change the organic matter into humus.
Roots too need air to breathe.
Without air, roots die.
They cannot go on feeding the plant (see Booklet No. 1, page 28).
· How to give the soil air.
When you work the soil, air enters into the soil.
If there is too much water the air does not circulate well.
Water prevents air entering the soil.
So ditches are made to get rid of the surplus water.
If the soil structure is good the air circulates well.
To get a good soil structure, there must be humus.
Humus makes it easier for air to circulate in the