Fertilizer application

How fetilizer is been applied
The most common way to maintain or to restore soil fertility or to replace minerals that are essential for plant growth is through the application of commercial fertilizers. A fertilizer is any material added to the soil to supply one or more essential minerals for plant growth. A soil amendment on the other hand is used to alter physical and chemical properties of the soil e.g. (using lime to improve the physical characteristics of a clay a soil and to lower its acidity). Fertilizer allows a crop producer to apply a specific essential mineral or group of minerals in precise concentrations to attain maximum yield. Commercial fertilizers like urea, sulphate of ammonia, calcium nitrate - supply Nitrogen to plants.
Single super phosphate supply phosphorous and muriate of potash supply potassium. A mixed fertilizer will supply all the three elements, that is NPK, fertilizer e.g. 15-15-15 i.e. contain 15 percent of by weight of each of N. P and K. the remaining 55 percent represent inert carrier for the useful nutrients . Fertilizer contains additional elements like magnesium e.g. (NPKMg 18-15-14-2).
INSECT PESTS AND DISEASES CONTROL
Insects like weeds that reduce crop yields are pests of crop plants. Insect pests and diseases impair the quality and reduce the quantity of harvest. The magnitude of the yield reduction varies with the crop, the pest and other factors from very slight to total crop failure. Crop quality is impaired through smaller and discoloured fruits, changes in taste the presence of contaminants from the pest. Thus control of pests and diseases is a vital agronomic practice. Crop pests include; stem borers (maize), aphids, flowers thrips and pod borers (cowpea). The cheapest and most' effective control of pest and diseases is to use pest and disease resistant varieties where these are available. However, specific chemicals are available for the control of these pests and most diseases on the field.