Residual and direct effect of integrated nutrient management on growth, yield, monetary efficiency, nutrient uptake of cowpea and soil properties under grain amaranth (Amaranthus hypochondriacus L.)-cowpea [Vigna unguiculata (L.) Walp] cropping sequence in Inceptisols of Western India

A field experiment was conducted for two years in Deep Black Soils to study the residual and direct effect on growth, yield, monetary efficiency, nutrient uptake and soil properties after harvesting of cowpea under grain amaranth (Amaranthus hypochondriacus L.)-cowpea [Vigna unguiculata (L.) Walp] cropping sequence. There were six treatments applied to grain amaranth and each plot of rabi grain amaranth was equally divided into four parts to summer cowpea. There was beneficial residual effect of integrated nutrient sources on cowpea and significantly maximum root nodules per plant, leaf area index, chlorophyll content, dry matter accumulation per plant, number of pods/plant, grains/pod, seed yield, total biomass yield and nutrient uptake (N, P2O5 and K2O) were noted under treatment RDN50 FYM + RDN50 BC (T-6) and significantly static with RDN50 CF + RDN50 BC (T-5) and RDN50 CF + RDN50 FYM (T-4). Soil status was also improved in terms of bulk density, organic carbon content and available nutrients in soil after harvesting of cowpea crop. Direct application of RDF levels to cowpea in summer season is concerned, the treatments RDF100 (F-4) recorded significantly higher values of all parameters as well as improved soil physical and chemical properties. Thus, the growth and yield attributes of cowpea as well as soil properties determined during two crop cycles were improved due to the application of manures in sole or in combination with chemical fertilizers.

Automated summary

The study found that integrated nutrient sources had a beneficial residual effect on cowpea, while direct application of recommended fertilizer levels also significantly affected cowpea growth and soil properties.