Substitution of fertilizer-N with biogas slurry in diversified rice-based cropping systems: Effect on productivity, carbon footprints, nutrients and energy balance

• Published in: Field crops research Vol. 307; p. 109242
• Main Authors: Mohanty, Samanyita, Saha, Sushanta, Saha, Bholanath, Asif, Sk Md, Poddar, Ratneswar, Ray, Manabendra, Mukhopadhyay, Swapan Kumar, Hazra, Gorachand
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-03-2024
• Subjects: Biogas slurry; Carbon footprints; Cropping system diversification; Energy balance; Sustainable yield index; Biogas slurry; Energy balance; Carbon footprints; Cropping system diversification; Sustainable yield index
• ISSN: 0378-4290
• DOI: 10.1016/j.fcr.2023.109242

Cropping system diversification under integrated nutrient management is an important tool for enhancing crop productivity, maintaining soil nutrient and energy balance while restoring environmental quality and sustainability. A field experiment was conducted for seven consecutive cycles with three rice-based cropping systems (C1: rice-mustard-jute; C2: rice-wheat-maize+greengram; C3: rice-lentil-sesame) under multiple irrigated conditions and four nutrient management practices (NPK fertilizers and biogas slurry (BGS) in various combinations). Comprehensive assessment of system productivity as well as sustainability, nutrient balance, energy and carbon footprint (CF) of different cropping systems under the influence of inorganic-organic fertilization were analysed to know the possible environmental impact. Irrespective of the cropping systems, the highest system rice equivalent yield (REY) (7.78 t ha−1) was recorded with 100% NPK fertilizers, whereas, substitution of chemical fertilizers with BGS for supplying a part of N, P and K requirement of different crops in the cropping system resulted in higher sustainable yield index (SYI). Positive apparent soil N and P balance were observed irrespective of cropping systems and nutrient management practices, however, the soils under all the treatments suffered an apparent loss of K. The rice-wheat-maize+green gram (C2) system dominated in terms of productivity and soil fertility, over the others, whereas substitution of NPK fertilizers by BGS resulted in a significant increase of available N, P, K, S, B and cationic micronutrient (Fe, Mn, Cu and Zn) content in the soil over 100% NPK fertilizers. However, sole application of BGS resulted in higher build-up of soil organic carbon. The energy ratio was higher in the rice-mustard-jute cropping system with 100% NPK fertilizers application (6.57 and 6.13 kg MJ−1 respectively) due to higher energy output to input balance, however, the specific energy was higher in the rice-lentil-sesame system with sole BGS application (6.13 and 6.25 kg MJ−1 respectively). In contrast to the C output and carbon footprint (CF), the carbon sustainability index (CSI) was reported highest in the rice-mustard-jute system (12.28) while the lowest was recorded in the rice-wheat-maize+green gram system (9.14). Therefore, legume inclusive cropping along with organic nutrient sources could be considered as an effective option to maintain crop productivity, soil nutrients and energy balance while reducing carbon footprints in the areas where intensive cultivation is predominated.
•Integrating slurry with fertilizers and legume inclusion was found more sustainable.•Inclusion of legume and slurry maintained positive soil apparent N and P balance.•Rice-mustard-jute with fertilizers showed higher energy ratio and specific energy.•Rice-lentil-sesame with sole slurry showed higher energy ratio and specific energy.•Low footprint and high C sustainability in rice-mustard-jute reduces global warming.