Effect of integrated nutrient management in a soybean-wheat crop sequence on the yield, micronutrient uptake and post-harvest availability of micronutrients on typic ustochrepts soil

Abstract

A field experiment using various levels of phosphorus, farmyard manure (FYM) and biofertilizers was undertaken at Udaipur during 2001–02 and 2002–03 to observe the direct effect of the treatments on the yield and micronutrient uptake of soybean and their residual effect on the yield and micronutrient utilization of a subsequent wheat crop. The results revealed that the seed/grain yield of soybean and wheat significantly increased with the application of increasing levels of P, FYM and biofertilizers. The integrated use of P, FYM and biofertilizers was able to replace 20 kg P 2 O 5 ha −1 to soybean and 10 kg P 2 O 5 ha −1 to wheat.The application of increasing levels of P, FYM and biofertilizers significantly enhanced the uptake of Zn, Cu, Mn and Fe by soybean and wheat. Among the biofertilizers, dual inoculation with phosphate-solubilising bacteria (PSB) + vesicular arbuscular mycorrhiza (VAM) gave the best performance. The integrated use of P levels and biofertilizers significantly improved the Zn and Fe uptake of soybean. The highest Zn and Fe uptake (125.77 mg kg −1 and 562.03 mg kg −1 , respectively) was recorded with the combined use of 40 kg P 2 O 5 ha −1 + dual inoculation. The application of FYM and P levels resulted in a significant improvement in the organic carbon, CEC, available N and P, porosity and hydraulic conductivity of the soil after the wheat harvest. Among the biofertilizers, dual inoculation led to maximum soil-available P. Phosphorus application gave a significant decrease in the DTPA-extractable Zn and Fe content of the soil after the harvest of wheat. FYM application significantly enhanced the DTPA-extractable Zn, Cu, Mn and Fe contents of the soil.