One way to improve soil fertility is the use of green manure. Green manure is a field crop which is destined to be ploughed into the soil. Usually this will be a leguminous crop because, through nitrogen fixation at the roots, they have a good fertilizing effect on the soil.
Green manure can be planted as a separate crop or between two main crops. It can also be used by intercropping with a main crop.
Advantages of green manure are similar to these of normal manure. On a fertile soil the plants develop better, which will increase their tolerance against pests and diseases.