Response of autumn sown black gram as influenced by cobalt, potassium and boron nutrition under Indian subtropics

Abstract

Black gram [Vigna mungo (L.) Hepper] is a widely grown pulse crop assuming considerable importance of food and nutritional security in India. A two-year experiment was conducted to find out the effect of cobalt (Co), potassium (K), and boron (B) on growth, yield, quality, and production economics of autumn sown black gram (variety: Pant Urd 31) under Gangetic alluvium soil (order: Inceptisol) in a split plot design with two different combinations of soil incorporation of Co as main plot and five foliar nutrition levels of K and B either single or in combination as subplot treatments during autumn seasons of 2020 and 2021. Pooled estimation revealed that crop growth rate, leaf area index, net assimilation rate, pods per plant, seeds per pod, seed yield, and benefit-cost ratio were significantly higher (p ≤ 0.05) with 4 kg ha−1 soil Co and foliar 1.25% K + 0.2% B applications as compared to no cobalt application and no spray respectively. This particular combination of soil application of Co along with foliar K + B spray also stimulated symbiotic efficiency, chlorophyll biosynthesis, and nitrate reductase activity along with improving the nutrients and protein contents in harvested seeds. Fluctuations in yield attributes explained about more than 85% variations in seed yield of both years through linear regressions. Thus, this unique combination of soil Co application along with foliar K + B spray has immense potential as an economically profitable strategy to facilitate substantial growth and physiological efficiency of an autumn-grown rainfed black gram to upgrade its production potential and quality.