Divergent responses of optimal land and water allocation to different hydrological regimes in the agricultural water-food-carbon nexus system

Abstract

Frequent changes in the hydrological regimes lead to divergent responses of water, food, and carbon (C) emissions in agricultural production, which challenge sustainable agricultural development. Therefore, this study proposed a systematic multi-objective non-linear programming model for investigating divergent responses of optimal land and water allocation to different hydrological regimes from the perspective of the agricultural water-food-carbon (AWFC) nexus framework. The model was capable of simultaneously tackling the trade-offs among water consumption, economic benefit, and C emissions by integrating with spatial–temporal water footprint (WF) and carbon footprint (CF) theories. The universal cropping patterns in each spatial water function zone that adapted to the spatiotemporal variations of hydrological regimes could also be obtained. The applicability and effectiveness of the proposed methodology were verified by a real-world, provincial-scale case, i.e., Jiangsu Province, southeast China. As for the actual scenario, the optimal scheme under normal, wet, and dry years highlighted the significance of improvement in water-saving (10.31%–12.26%), while showing a slight increase in net economic benefit (2.68%–2.85%) and low-carbon agricultural competitiveness (1.21%–3.58%). It was found that the wet year performed the greatest water-saving potential, and the dry year showed the strongest low-carbon agricultural competitiveness. The optimal cropping patterns suggested that it was a promising management strategy to enhance the comprehensive benefits related to the economy, water, and carbon by increasing the planting proportion of high-value crops with low WF and CF. This study provided scientific methodology and instructions for balancing the trade-off among economy, water, and environment components in sustainable agricultural development.