Evaluation of biological commercial inoculants on soybean production in Bungoma county, Kenya.

Nitrogen (N) and Phosphorus (P) are the major nutrients limiting crop production in sub-Saharan Africa (SSA) leading to food insecurity. Replenishing these soil nutrients is a major capital investment, which partly answers the question of sustainable crop production. Commercial inoculants (e.g. rhizobial and mycorrhizal inoculants) enhance the productivity of specific legumes (soybean). On-farm demonstration trials were conducted during the 2010 short rains to evaluate the effects of these commercial inoculants on soybean production in Bungoma county, western Kenya. Inoculated soybean seeds with rhizobia (Legumefix) and one of the mycorrhizal inoculants were planted in plots of 4.5 m x 5.0 m with treatments applied in RCBD per farm at seven sites. Each farm was a replicate in a multi locational design. Analysis of Variance was done to determine the effects of the products on soybean nodulation and grain yields. Results showed that there were significant (P<0.05) differences in nodulation at 50% podding. Treatments Legumefix + Myco Tea (1.3 g plant-1), Legumxefix + Myco Apply soluble Maxx (1.2 g plant-1) and Legumefix + Endorize (1.17 g plant-1) had significantly higher nodulation compared to the control (0.44g plant-1). At harvest, grain yields differed significantly p<0.05 among the treatments with Rhizatech + Legumefix giving (0.65 t ha-1) and Legumefix +P (0.62 t ha-1) as compared to control which (0.26 t ha-1). These results shows that Legumefix contributes significantly to soybean production and a positive effect is realised when combined with either inorganic P or other commercial inoculants . Use of agricultural commercial inoculants is an enviromental friendly and economically sound means of improving soil fertility.