Trade-offs and synergies of food-water-land benefits for crop rotation optimization in Northeast China

In agricultural management, selecting the appropriate crop rotation type (CRT) is crucial for sustainable development. Despite the focus on food production, water conservation, and farmland protection, systematic and quantitative analyses of the interrelationships and benefits among food, water, and land under different CRT scenarios are lacking. This gap hinders the achievement of goals and limits effective support for agricultural planning. This study utilized yield, water use efficiency (WUE), and farmland degradation and restoration (FDR) conditions to measure benefits related to food production, water resource conservation, and farmland protection. Taking the Northeast China (NEC) region as an example, nine major CRT zones were identified, and their integrated "food-water-land" benefits were quantitatively assessed. The findings revealed that there are significant differences in the annual average yield and WUE under different CRTs. Specifically, the average yield of the Maize-continuous-cropping or Rice-continuous-cropping zone is much higher than that of the Soybean-continuous-cropping zone; the WUE was highest in the Soybean-continuous-cropping zone, with a multi-year mean of 1.105 kg·C·m⁻³. The NPP-WUE framework for FDR detection indicated that crop rotation is more conducive to farmland protection than continuous-cropping, as a higher proportion of restoration area was detected. By assessing the trade-offs between CRT and "food-water-land" benefits, the results show that when prioritizing a single goal of food production, water resource conservation, or farmland protection, the best CRT for farmland is Maize-continuous-cropping, Soybean-continuous-cropping, or Soybean-Other crops rotation, respectively. When multiple goals are considered, Maize-continuous-cropping or Soybean-continuous-cropping is the most ideal. Therefore, maintaining a large area of maize while expanding soybean planting in the NEC is reasonable. In the NEC, we recommend adjusting Maize-Soybean and Rice-continuous-cropping; the former prioritize shifting to Maize or Soybean continuous-cropping, and the latter prioritizes shifting to Maize-Rice rotation. This study offers valuable insights into the trade-offs and optimization of CRTs, thereby contributing to sustainable agricultural development.