Responses of Maize to Application of Compound Fertilizers on Farmer's Fields in Ten Districts of Tanzania

Abstract

In many areas of Tanzania more than one essential element is lacking in the soil and needs to be applied as fertilizer to obtain optimum maize yields. Over much of the country both nitrogen and phosphorus are required together, while in some areas potassium is also essential if yields are to be raised above subsistence levels. Though responses to N or P alone are sometimes striking, it is frequently necessary to apply both to obtain an economic return above the fertilizer costs in the year of applic1tion, for the NP interaction is often very important. However, in many areas heavy fertilizer dressings are not necessary for good responses. Such applications in dry areas may fail to give economic returns, or cause a depression in yield compared with lighter dressings, and they can also bring about marked changes in the base status of the soil. Therefore, there is much to be said for applying light dressings of twin or triple-nutrient fertilizers. Quite apart from the insurance policy of alleviating all major deficiencies in one application, such compounds are usually much cheaper to transport than bulky single nutrient fertilizers. Use of compounds is also in line with the world trend towards greater predominance of these.