Effect of fertilizers at various levels of recommended dosages with organic manures and seed inoculation on phosphorus fractions in postharvest soils

A field experiment was conducted at KVK, Srinagar during two consecutive Kharif of 2009-10 and 2010-11 to study the effect of fertilizers at various levels of recommended dosages with organic manures and microbial inoculation of seeds on the contents of different P fractions (Fe-P, Al-P and Ca-P) in postharvest soils under temperate conditions. The field experiment with soybean [Glycine max (L.) Merin] as the crop was laid out with 18 treatments viz. three levels of recommended dosages (RD) of inorganic fertilizers (50, 75 and 100% RD) along with organic manures (control, and FYM and Dalwood, both at 10 t ha(-1)) and biofertilizers by means of seed inoculation (control and dual inoculation with Rhizobium + PSB), in complete randomised block design. Each treatment was replicated thrice. The results revealed that the application of inorganic fertilizers, organic manures and bio-inoculation (INM) significantly increased the Fe-P, Al-P and Ca-P fractions in postharvest soils. With the application of fertilizers at 100 per cent level of RD along with the manures and seed inoculation, postharvest soil Fe-P, Al-P and Ca-P contents were higher than when the fertilizers were applied at 50 and 75 per cent level of RD. FYM proved to be superior to Dalweed towards increasing the levels of soil P fractions (Fe-P, Al-P and Ca-P). The levels various inorganic P-fractions increased also with dual inoculation of Rhizobium and PSB of the seeds.