Mulching and nitrogen management in peanut cultivation: an evaluation of productivity, energy trade-off, carbon footprint and profitability

Field study was conducted during winter seasons (November-March) of 2015-2016 and 2016-2017 at the Research Farm of Bidhan Chandra Krishi Viswavidyalaya, West Bengal, India, with an aim to investigate the crop productivity, energy and C budget, carbon footprint and economic sustainability of peanut cultivation fertilized with varied levels of nitrogen under polythene mulching. The experiment laid out in split-plot design comprised of two mulching practices as the main-plot treatments and seven doses of N with or without supplementation of Rhizobium bio-fertilizer as the sub-plot treatments. Fertilization with 100% recommended dose of nitrogen (RDN) + Rhizobium under polythene mulching brought about significant enhancement in pod yield over other nutrient management practices. The effects on yield attributing characters were similar to that of pod yield. Energy indices namely net energy gain, energy productivity, energy intensiveness and energy profitability were the highest with 100% RDN + Rhizobium, irrespective of mulching situations. However, the maximum values of specific energy and nutrient energy ratio were recorded when the crop received 50% RDN with and without Rhizobium, respectively, under mulching and non-mulching situations. Human energy profitability was always greater under mulching situations over non-mulching. Total estimated carbon footprints improved with increase in N level from 0 to 100% RDN with Rhizobium under polythene mulching over non-mulching situations. Highest value of C sustainability index was also observed with polythene covering particularly with the application of 100% RDN + Rhizobium. This treatment combination also proved its superiority with respect to economic benefits in peanut cultivation.