Crop yield, nutrient uptake, nutrient use efficiency and soil properties of soybean-mustard system as influenced by soil amendments in degraded vertisol of western India

Amelioration of salt affected soils aims to reduce exchangeable sodium percentage (ESP), improve crop growth and yield. A field study was conducted with soybean-mustard cropping system for four consecutive years (2016-2019) to study the effect of soil amendments on crop yield, nutrient use efficiency and soil properties in degraded vertisol of North Western India. Treatments consist of various combinations of gypsum, farm yard manure (FYM) and crop residue (CR) with recommended fertilizer doses (RNPK), were laid in random block design with three replications. Application of gypsum alone and combined with organic amendments, showed pronounced decrease in ESP, slight reduction in pH, increased bioavailability of nutrients, as reflected by higher nutrient uptake and crop yields. Grain yield improvement in soybean (37-41%) and mustard (58-63%) was recorded in plots receiving RNPK + Gypsum + CR + FYM, RNPK + Gypsum + CR or FYM over only chemical fertilizer treatments. Combined application of gypsum with organic amendments increased N, P, K and S uptake by 75, 76, 84 and 114%, respectively over RNPK alone in soybean-mustard system. Highest values of apparent recovery efficiency and agronomic efficiency of N, P, K, S was registered under RNPK + Gypsum and RNPK + Gypsum + CR/FYM. Highest physiological and internal efficiency of nutrients was registered under RNPK and decreased with amendment application. This study revealed the combined use of FYM (10 t ha(-1)), CR (3 and 1.5 t ha(-1)), gypsum (2.5 t ha(-1)) with fertilizers as a sustainable technology for reclaiming soil sodicity, improving nutrient use efficiency and crop productivity under soybean-mustard system.