Soil is Fertile When it Contains:
1. Ample supplies of organic materials.
2. The source of nitrogen.
3. Sufficient soluble compounds of the mineral elements needed for the growth of food plants.
The above requirements coupled with satisfactory surface topography. Physical properties, subsoil drainage and application of adequate water at proper intervals leads to the production of rich crops.Maintenance of Soil Fertility:
Soil Fertility can maintained by the following ;
1. By use of proper cultivation methods.
2. By spreading all the farmyard manure which supply organic materials as well as fertilising element.
3. planting of different crops in rotation on different areas.
4. Application of carefully selected commercial fertilizers.
5. Ploughing under or disking-in of crop, plants or native vegitation or green manures adds organic matter and fertilising elements. Deep ploughing is undesirable.
6. Stubblesmulch farming: It is a recently developed method of crop tillage that leaves the stubble and other residues of the preceeding crop on or close to the soil surface to provide a surface mulch. The mulch tends to conserve moisture and soil fertility. It reduces compaction of the surface soil by rainfall, decreases surface run-off and largely prevent soil erosion by wind.
7. Suitable procedures for reducing or controlling erosions may constitute important role in maintaining soil fertility.
8. Irrigation with silty water.
9. Soils of acidic nature may show improvement with the application of calcium oxide to the extent of 1000 kg per hectare. shortage of lime leads to dark colour of leaves and its excess may lead to their scorching.