Effect of irrigation schedule, residue incorporation and nutrient management on system productivity and profitability of soybean (Glycine max)wheat (Triticum aestivum) cropping system in Vertisols of Rajasthan

Abstract

A 3-year field experiment was carried out at Kota, Rajasthan during 201516 to 201718, to study the effect of irrigation schedule, residue incorporation and nutrient management on system productivity and profitability of soy- bean [Glycine max (L.) Merr.]wheat (Triticum aestivum L.) cropping system in Vertisols of Rajasthan. The treat- ments consisted of 24 combinations of 2 irrigation schedules in soybean, viz. 1 irrigation at flowering stage and 2 irrigations at flowering and other pod-development stages -in main plots; 4 wheat residue-management practices, viz. sowing of soybean after wheat-residue burning, wheat-residue incorporation without irrigation, residue incor- poration with irrigation and application of urea @ 25 kg/ha and residue incorporation with irrigation and application of urea @ 25 kg/ha + cellulolytic microbes @ 2.0 kg/ha in subplots; and 3 nutrient-management practices, viz. 75% recommended dose of fertilizers (RDF), 100% RDF (20 kg N, 40 kg P O , 40 kg K O/ha) and 125% RDF in sub- 2 5 2 subplots. The experiment was laid out in a split split-plot design with 3 replications. Wheat crop was sown every year with the adoption of recommended package of practices. Pooled data of 3 years revealed that 2 irrigations at flowering and other at pod development stages-in soybean crop significantly increased dry-matter production, unit- area efficiency, branches/plant, pods/plant, seeds/pod, seed index, seed and straw yields and net returns of soy- bean, grain yield of wheat, soybean-equivalent yield (SEY), profitability, production- and economic-efficiency of system, available N, P and K status of soil after harvesting of wheat and soybean as compared to 1 irrigation at flowering stage. However, available K status of soil after harvesting of soybean was found non-significant in rela- tion to irrigation. Wheat-residue incorporation with irrigation and application of urea @ 25 kg/ha + cellulolytic mi- crobes @ 2.0 kg/ha resulted in the highest growth and yield attributes, seed and straw yields and net returns of soybean, water-use efficiency (WUE), water productivity (WP), soybean-equivalent yield (4.51 t/ha), system profit- ability ( 96,520/ha), production (12.35 kg/ha/day) and economic (264 /ha/day) efficiency of system, organic car- bon, bulk density of soil after harvesting of soybean and N, P and K status of soil after harvesting of both soybean as well as wheat over wheat-residue burning. Application of 125% RDF resulted in the maximum growth and yield attributes, seed (1.51 t/ha) and straw (2.17 t/ha) yield, net returns ( 25,700), benefit: cost ratio (1.09) of soybean and SEY (4.44 t/ha), system profitability ( 95,740/ha), production (12.15 kg/ha/day) and economic efficiency (262 /ha/day), bulk density (1.42 Mg/m3), N (282, 288 kg/ha) P O (24.6,25.9 kg/ha) and K O (293, 299 kg/ha) of 2 5 2 soil after harvesting of wheat and soybean respectively.