Integrated nutrient management on oat + grasspea intercropping system: an evaluation of system productivity, economics, energetics and carbon footprint.

ABSTRACT

A field investigation took place at Central Research Farm of Bidhan Chandra Krishi Viswavidyalaya, West Bengal, India during winter seasons of 2020-21 and 2021-22 with the aim to evaluate system productivity, economics, energetics and carbon footprint (CF) of oat + grasspea intercropping systems under different integrated nutrient managements (INM). The experiment was executed in split-plot design with 4 cropping systems in main plots and 4 levels of nutrient management in sub plots. The 33 intercropping system of oat + grasspea ensured highest system productivity, whereas sole grasspea stood best in terms of economics, energetics and environment safety by lowering CF. Notably, INM involving 75% N through urea + 25% N through vermicompost registered significantly higher system productivity in case of 33 oat + grasspea intercropping system (CS4N3) (18.77 q ha-1). Further, this intercropping system yielded high economic profitability (net return US$ 430.4 ha-1, benefit-cost ratio 1.71) as well as energy indices (energy output 71179.1 MJ ha-1, net energy gain 60352.0 MJ ha-1, energy ratio 6.57 and energy profitability 5.57). CF was also found relatively low under CS4N3 (Yield scaled CF 62.2 kg CO2-e q-1). Furthermore, high carbon efficiency (7.92) and carbon sustainability index (6.92) were also exhibited by CS4N3 as it produced maximum carbon output (1801.2 kg ha-1). In conclusion, the 33 oat + grasspea intercropping system using INM can be viable option to ensure economic and energy viability and minimize greenhouse gas emissions without compromising system productivity. Particularly, this intercropping system combined with 75% N through urea + 25% N through vermicompost as INM option can be recommended for the cereal and legume growers of India, specifically under intensive cropping scenario.