Spatial patterns of yield-based cropping suitability and its driving factors in the three main maize-growing regions in China.

Reasonable crop planting division is important for farmers to grow suitable plants and for decision makers to make short- and long-term plans. In this study, we assessed the cropping suitability for maize in the three main growing regions in China, including the North China Spring Maize Region (NCS), the Huanghuaihai Summer Maize Region (HS), and the Southwest China Mountain Maize Region (SCM). We determined the spatial patterns of cropping suitability for maize and the dominant climate and soil drivers by assessing both yield level and yield stability (high-stable index (HSI)) under four production input levels (simulated yield potential (Yp), water-limited yield (Ypw), and water-limited-soil-constrained yield (Ypws) by APSIM-Maize model and actual yield (Ya)) during the period of 1981-2010. According to the HSI of Yp for maize, optimal and suitable areas for maize production were focused in NCS and HS. In SCM, the percentages of subtotal optimal and suitable areas for both simulated Ypw and Ypws to total regional area were higher than those in NCS and HS. Yield level of Ya was significantly higher in NCS and HS than in SCM, while yield stability of Ya in NCS was significantly lower than that in the other two study regions. Based on Ya, HS (SCM) showed the largest (smallest) optimal and suitable areas for maize production. In addition, the percentage of subtotal optimal and suitable area to total regional area is the highest in HS. Under the Yp level, solar radiation was the dominant factor for cropping suitability in the three study regions. Under the Ypw and Ypws levels, precipitation was the driving factor for cropping suitability in NCS and HS, while solar radiation and soil water properties were the driving factors for cropping suitability in SCM. These results can be used to assist local policy makers in dividing maize-growing regions in China. Hence, local farmers could choose the most suitable varieties accordingly in order to maximize the yield production while maintaining a relatively high yield stability.