Exploration of the optimal low-carbon peanut rotation system in South China

Abstract

CONTEXTPeanut is an important economic and oil crop that has the potential to contribute to low-carbon agriculture. However, there is scarcity of comprehensive evaluations regarding the impact of various peanut rotation systems and their contribution to low-carbon agriculture. OBJECTIVEThe research aims to comprehensively evaluate the contribution of peanut rotation systems to low-carbon agriculture in South China, and expected to explore the optimal low-carbon peanut rotation system in this area. METHODSThree cropping patterns were compared over a four-year experimental period: wheat–peanut (W-P) rotation, rape–peanut (R-P) rotation, and peanut monocropping (MP), under two types of initial fields (paddy and dryland). The carbon footprint (CF), product carbon footprint (PCF), carbon sequestration, food carbon cost (FCC), soil carbon characteristics, net economic benefit, and ecosystem service values of C sequestration of three rotation ecosystems were studied. RESULTS AND CONCLUSIONSOur findings reveal that R-P, WP, and MP had total CFs of 1.788, 3.882, and 1.096 t CO2-eq·hm−2, respectively. Agricultural material input, particularly N fertilizer, was the primary CF contributor. R-P had higher carbon sequestration amount and efficiency than WP. Notably, dryland-initial fields of both R-P and WP had higher carbon sequestration efficiency (71.1 % and 17.6 % higher, specifically). Our soil carbon analysis indicates that both plant residue quality and initial field type influence C sequestration. While WP had the highest PCF (0.552 t CO2-eq t−1) and FCC of protein (3.428 kg CO2-eq·kg−1), fat (3.791 kg CO2-eq·kg−1), and energy (0.135 kg CO2-eq·1000 kcal−1), R-P showed the highest net income (3333.3 US$·hm−2) and higher ecosystem service value of C sequestration (−5.6 US$·hm−2). Furthermore, our findings reveal that common crop rotations in South China have higher CFs than the tested peanut-based systems. Therefore, R-P rotation is the most suitable system for low-carbon agriculture in the research area among these three rotations due to its lower carbon cost and higher economic benefits. And the advantages, disadvantages and uncertainties of different low-carbon agricultural indicators have also been analyzed. SIGNIFICANCEOur study would contribute to exploring agroecosystems management ways and methods to mitigation climate change and provide references for the establishment of evaluation criteria for low-carbon agriculture.