Influence of phosphorus sources, levels and solubilizers on yield, quality and nutrient uptake of soybean (Glycine max)-wheat (Triticum aestivum) cropping system in southern Rajasthan

An experiment was conducted during 1999-2000 and 2000-01 to study the effect of phosphorus sources, levels and solubilizers on yield, quality and nutrient uptake of soybean [Glycine max (L.) Merr.]-wheat (Triticum aestivum L. emend. Fiori & Paol.) cropping system in alkaline calcareous soils of Udaipur. Phosphorus application,through single superphosphate significantly increased the seed yield, oil content and N and P uptake of soybean over Udaipur rock phosphate-single superphosphate (1: 1) mixture. However, both the sources performed equally in imparting the residual effect on grain yield of succeeding wheat and thereby the soybean-equivalent yield of the system. Significantly higher N and P uptake of the succeeding wheat crop were recorded due to single superphosphate - Udaipur rock phosphate (1: 1) mixture, while higher N uptake of the whole system was recorded under single superphosphate treatment. Significant enhancement in seed yield, protein and oil content and N and P uptake of soybean were recorded upto 38.7 kg P/ha. Application of 38.7 kg P/ha increased the seed yield and N and P uptake of soybean by 13.3, 18.7 and 30.5% over 12.9 kg P/ha respectively. The maximum productivity and N and P uptake of succeeding wheat and system as a whole were recorded at 38.7 kg P/ha application to soybean. An incorporation of farmyard manure @ 10 tonnes/ha with and Without phosphorus-solubilizing bacteria significantly improved the yield (9.3 and 7%), quality and N (17.8 and 13.2%) and P (17.15 and 13.4%) uptake of soybean, and yield (9.6 and 7.5%), N (16.7 and 13.6%) and P uptake (15.9 and 12.3%) of succeeding wheat crop and hence the yield of system as whole (9.5 and 7.3%) respectively over phosphorous-solubilizing bacteria alone. Application of 25.8 kg P/ha to wheat crop improved its yield (13.8%) and N and P uptake (20.4 and 38.4%) thus emphasizing the need for P application to both the component crops of the system.