Fallows and Cover Crops

Fallows

Fallows is the  word used to describe a piece of land that is left unplanted for a season or more. This system is adopted in many parts of west African where land is abundant. Bush fallowing on the other hand involves growing crops on a piece of land until the land is no longer productive. The land is them abandoned and allowed  to go back to bush for six to twelve years before it is used again. The farmer then moves to other areas to make new farms.

   There are many advantages and disadvantages in this type of system. During fallow periods, plant nutrients build up ad a result of formation of organic matter.

  Fallowing is designed to clean the land , leaving it free of pests, diseases and weeds. It is also relatively cheap because no extra expenses on fertilizers are involved.

  The system , however , encourages repeated land clearance which involves energy , time and in the process valuable forest areas will be destroyed. During clearance, loss of humus and soil fertility results from burning. After clearing , the soil is left bare and this encourages soil erosion.

   Bush fallowing is nevertheless becoming rare with the increasing population pressure on land, and with improved agricultural technology because of the introduction of crop rotation is and chemicals for destroying weeds before or during the cropping of the land.

   However, the system may continue to persist in those parts of tropical Africa where land tenure system encourages people to temporarily acquire land for farming.

Cover crops

These are crops that are planted to  protect the soil surface from being washed away by the rain. The soil is thereby protected from the mechanical action of rain by stopping and breaking up the rain drops before they hit the soil. This prevents surface runoff and leaching of the soil. The crops also prevent rays of the sun from overheating the soil surface which may lead to water evaporation from the soil surface. When a piece of land is lying fallow before the next crop, cover crops are usually planted to occupy such land.

   Many cover crops are leguminous (legumes) e.g beans , mucuna, centrosema, pueraria.  Many grasses and short lived trees are Also used as cover crops. The legumes are able to make nitrogen In their root nodules and this nitrogen is released into the soil to improve soil fertility. Short lived trees act as wind breaks and cut down wind movement thus reducing erosion, rates of transpiration from crops and evaporation from the soil. Cover crops enrich the soil with their fallen leaves, when these leaves decay.