Maximizing maize yields while minimizing soil erosion in Mollisol regions of China and the United States

As vital global granaries in Mollisol regions, the Upper Mississippi River Basin (UMRB) in the U.S. and Songhua River Basin (SHRB) in China face growing demands to improve maize yields while avoiding soil erosion. We evaluated effects of individual and integrated technologies on maize yield, yield stability, and soil erosion from 2001 to 2018 with a fully calibrated Soil and Water Assessment Tool (SWAT) model. Results showed that mean yields in the SHRB lagged 4.0 t ha −1 behind the UMRB, although both regions exhibited large yield variations (CV > 10%). High-density planting provided limited yield gains, but reduced erosion by ~30%. Irrigation markedly increased yield by 11% for UMRB and 33% for SHRB, and improved yield stability (CV < 5%), but increased erosion by >10%. Integrated irrigation and high-density planting boosted yields, mitigated erosion, and increased net returns. Yet a 1.5 t ha −1 difference remained between China and the U.S., underlining the need for germplasm improvement to close the productivity divide.