Rhizospheric Micro-flora, Nutrient Availability and Yield of Green Gram (Vigna radiata L.) as Influenced by Organic Manures, Phosphate Solubilizers and Phosphorus Levels in Alfisols

Field experiments were conducted during two consecutive kharif seasons of 2004 and 2005 at the Crop Research Farm, SKUAST-K, Shalimar campus, Srinagar, to assess the rhizospheric microflora, nutrient availability and yield of green gram as influenced by organic manures, phosphate-solubilizers and phosphorus levels in Alfisols. The results revealed that application of organic manures significantly increased the rhizospheric microbial population (bacteria, fungi and actinomycetes), available soil N P K, grain and straw yield of green gram. Among organic manures, application of FYM (10 t ha⁻¹) proved significantly superior to Dalweed (15 t ha⁻¹). Soil inoculation with P-solubilizers recorded significant increase in grain and straw yield of green gram, soil available N and P and bacterial and actinomycetes population, whereas fungal population significantly decreased due to inoculation. Among P-solubilizers, Pseudomonas proved significantly superior to Bacillus on yield of green gram, soil available P and bacterial population. Increasing levels of P up to 30 kg P₂O₅ ha⁻¹ significantly improved the grain and straw yield of green gram; microbial population (bacteria, fungi and actinomycetes) and soil available N; whereas available P of the post-harvest soil increased significantly up to 60 kg P2O5 ha⁻¹ level. The application of 60 kg P₂O₅ ha⁻¹ decreased microbial population significantly over 30 kg P₂O₅ ha⁻¹. Thus application of 30 kg P₂O₅ ha⁻¹ could be designated as the safe limit for maximum microbial build up in the green gram rhizosphere.