Modeling climatically suitable areas for soybean and their shifts across China

Crop suitability determines its distribution and yield in a given region and can be greatly affected by climate change. In recent decades, the distribution of soybean cultivation has undergone significant spatial shifts in China. However, whether this change matches with climatic suitability for soybean at a national scale has not been reported. Our objectives were to investigate the spatial distribution and shifts in climatically suitable areas for soybean from 1961 to 2017 and to determine whether actual production matches with climatic suitability in China. The MaxEnt model was used to simulate the presence probability of soybean from 1961 to 2017 based on soybean occurrence data and climate data across China. Regions were classified as climatically unsuitable or as having low, moderate, or high climatic suitability. Then, the overlay analysis was performed to assess spatial changes of soybean suitability and the consistency between climatic suitability and actual production. Accumulated temperature ≥ 10 °C, humidity index during the potential growing season, and annual temperature range were the major climatic factors that affected soybean distribution. Areas of high climatic suitability were mainly located in the Northeast and North-central Regions, and the total acreage of high suitability was 129.88 × 106 ha. Unsuitable areas for soybean contracted over the study period, whereas highly suitable areas migrated westward and southward. The climatic suitability for soybean across China has increased overall in the past decades. The area of improved climatic suitability from 1961 to 2017 comprised 14.60% of the entire land area of China and was concentrated primarily in the Northwest and North-central Regions. Nonetheless, consistency between climatic suitability and actual production decreased from 83.47% in 1985 to 65.16% in 2015. This may pose a risk to soybean production, especially in emerging major planting areas of the Southwest Region. This study described the distribution of climatically suitable areas for soybean, used spatial analysis to illustrate the extent to which climatically suitable areas overlap with actual production areas, and discussed possible solutions for improving soybean production at a national scale in China. This work has practical significance for optimizing the regional layout of soybean production and implementing countermeasures to address future climate change.