Performance of Soybean on Use of Various Nutrient Sources : Soil characteristics on application of Various Phosphorus Sources and Starter Nitrogen and how they affect soybean yield

Integration of legumes into farming systems is one of the Integrated Soil Fertility Management (ISFM) options for improving soil fertility. Farmers can save their cost of production by using legumes, which, in association with rhizobia, can fix atmospheric nitrogen. Soybean is an important legume compatible with the smallholder farming systems in many developing tropical countries. However, low P and N, a situation prevalent in many of these tropical regions can limit its performance. This book demonstrates results of a study carried out in Kigogo in Tharaka Nithi County and Kamujine in Meru County both in Kenya. Sources of P, with or without starter N application were evaluated while pursuing the following objectives: (1) to determine the effects of different phosphorus sources and starter N on soybean yield and selected soil chemical properties, (2) to evaluate the effects of different phosphorus sources and starter N on nodule numbers and soybean growth parameters. Finally, the study assessed the effects of different phosphorus sources and starter N on the amount of N fixed by soybean and their economic suitability.