Trade-off and driving mechanisms for farmland ecosystem services based on climatic zones and agricultural regionalization

Abstract: Farmland is one of the important terrestrial ecosystems that related to the national food security. There are some trade-offs among the farmland ecosystem services during sustainable development. But, it is still unclear on the trade-off relationship and driving mechanisms of farmland ecosystem services in the different climatic and agricultural zones. Among them, the Huaihe River Basin under the subtropical and warm temperate zones can be divided into the Middle-lower Yangtze Plain and the Huang-Huai-Hai Plain, in terms of agricultural zoning. Taking the Huaihe River Basin farmland ecosystem as the research object, this study aims to refine the trade-off mechanism of farmland ecosystem service using climate and agricultural zones. The core service functions were quantitatively analyzed (such as the food supply and soil conservation) from 1990 to 2019. Root Mean Square Error (RMSE) was then selected to evaluate the trade-off degree between them. GeoDetector was also used to reveal the natural and human drivers of changes in the trade-off relationship. The results showed that: 1) An overall growth trend was found in the food supply services of the study area. Specifically, the growth of food supply in the Huang-Huai-Hai Plain was significantly higher than that in the Middle-lower Yangtze Plain. Soil conservation services varied greatly in the different districts. A faster growth trend of climate zones was observed in the subtropical zone than in the warm temperate zone. A faster growth trend of agricultural zones was in the Middle-lower Yangtze Plain than that in the Huang-Huai-Hai Plain. By contrast, the average soil conservation value in the Huang-Huai-Hai Plain was higher than that in the Middle-lower Yangtze Plain. 2) There was an increasing trend with the significant spatial divergence in the trade-off between the farmland food supply and soil conservation services. The trade-off relationship was the most significant in the warm temperate Middle-lower Yangtze Plain agricultural zone, followed by the subtropical agricultural zone, and the warm temperate Huang-Huai-Hai Plain agricultural zone. 3) Both natural and human factors were dominated in the trade-off relationship between the food supply and soil conservation in the study area. There were only a few variations in the relative contributions of human factors and soil texture factors to the trade-off relationship between the two services in different zones. A significant variation was found in the contributions of climatic and topographic factors to the trade-off relationship between the two services in the different subdivisions. The contribution of topographic factors to the trade-off relationship was higher in the warm temperate Huang-Huai-Hai Plain agricultural zone than that in the rest two regions. There was also the great difference in the relative contribution of climatic factors. Therefore, the annual average temperature posed a higher influence on the trade-off relationship in the warm temperate Huang-Huai-Hai Plain agricultural zone, whereas, the annual precipitation was a higher influence in the other two regions. 4) Some recommendations were given for the decision making on the use and conservation of farmland in major food-producing regions. The spatial and temporal variability can also be fully considered for the trade-off between supply services (food production) and support services (soil conservation) of farmland ecosystems in different climatic and agricultural zones. At the same time, the universality of driving factors can also be critical to reduce the negative impact of human factors. The natural factors of different regions and the interaction mechanisms can be expected to combine with the human factors for the zoned policies, in order to improve the targeting policies in different climate and agricultural zones. The finding can also provide a scientific basis to promote the precise policy-making and synergistic development for the food and ecological security in different climatic and agricultural zones of the Huaihe River Basin.