关键词: 气候变化, 轮作系统, 种植效益, 气候风险, 适应

Abstract: As a major agricultural practice in mainland China, crop rotation that experiences multiple harvests during a certain period and in a same land plays a vital role in increasing its land productivity and securing national food production. To devise better adaption and increase national food production under a fasting warming world, it is necessary to add the understandings regarding statues of current crop rotation systems in China, impacts of climate change on the systems, and responses of the systems to various warming trajectories. This paper reviews latest works related to crop rotations, with particular focuses on the responses of crop rotations to historical and future climate change. Most studies investigate the interactions between crop rotation and climate change based on three methods: crop modeling, statistical analysis, and field experiment, each method exhibits specific defects and merits. Authors summarize current understandings about the influence of climate change on crop rotation from four aspects: crop growth, crop spatial distribution, cost and benefits, and production risks. Authors explore adaptive practices in rotations and in the end recommend research directions for the future. This review increases the understandings about the impact of climate change on crop rotations and provides useful information for developing wise rotation strategy in coping with climate change. Previous studies illustrated that climate change has already affected and would continue to influence crop rotations, but discrepancies existed among studies because differences in spatial and temporal scales, methodology, and research subjective. Majority of the studies showed that warmer climate and increasing heat resource made it possible for some rotation systems to move north, which had substantially altered crop patterns and shifted planting area for a few major crops. Higher temperature physiologically speeds up crop growth, accelerating crop phenology and leading to lower yield. But this acceleration, on the other hand, creates great opportunities for switching of crop varieties and replacement of crop type. The increases in total heat resources during the growing-season lead to spatial and temporal variations of climatic disasters, requiring reconsideration of conventional copping strategies. For example, although reduction of cold disaster has been observed in many crop areas, on the contrary, the occurrence of the cold disaster actually has increased recently in many crop areas due to shifting of planting boundaries and over-adaptations. Together with increased heat stresses under warming climate, these new disaster patterns posed additional threats for alleviation of agricultural climate disasters, jeopardizing the productivity, stability, and sustainability of many rotation systems. Theoretically, yield loss caused by climate change could be offset by appropriate adjustment of crop patterns, adoption of new crop varieties, such as cultivars with longer growth period, and optimization of management practices. However, because of complexity of the systems, we failed to make a concrete and consistent conclusion regarding the interactions between climate change and crop rotation based on reviewed researches. Future works are recommended to emphasize the integration of multi methods to increase understandings related to mechanism, comprehension, and systematization of crop rotation systems, and to pursue in-depth investigation with wider connection between climate change and crop rotation and decreasing research uncertainty.

Key words: Climate change, Crop rotation, Cost and benefits, Climatic risks, Adaption