SOIL FERTILITY MUST BE KEPT HIGH:

Te Ao Hou, December 1956, Page 47

SOIL FERTILITY MUST BE KEPT HIGH: The main purpose of a cover crop is to prevent the loss of plant foods and to build up soil fertility. At this time of the year when land becomes vacant after the harvest of spring sown crops, it is essential if the area is not to carry autumn planted vegetables, to sow down in one of the numerous cover crops available. Owing to the restricted areas in most home gardens it is necessary to crop the land intensively, and in many cases the humus content of the soil is at a very low level. Therefore legumes, such as Lupens, Field Peas, or Vetches are probably the best types of cover crops owing to the fact that legumes have the power of fixing what is termed free nitrogen, which the plant takes from the air and stores in the soil. At maturity, this is usually just before the blossoming period, the roots and plant contribute a very desirable form of nitrogen and organic matter. As decomposition takes place, nitrogen is slowly expelled into the soil, by what is known as bacterial action, and later is released as nitrate. In this form it is available too, and assimilated by plant life. Apart from the above element which is available, a large bulk of organic matter when dug in always improves the physical condition of the soil. For example, light soils are usually made to a no less degree heavier, whilst the texture of heavy soils will break down more readily and assume a more friable texture.