Spatio-temporal Change Of Cultivated Land Use In China And Its Impact On Grain Production Capacity

Cultivated land is the basis of human social and economic development,and the grain production capacity of arable land is the most essential reflection of the utilization of cultivated land resources.Facing the realistic background of"decreasing quantity and reducing quality"of cultivated land resources and the pressure of food production and supply security,the existing researches are mostly limited to the analysis of cultivated land changes on a single scale and the theoretical grain productivity measurement from the perspective of natural sciences.It is difficult to realize the guidance of cultivated land use practices and grasp of food security strategies.Therefore,studying the characteristics of the use of cultivated land resources in China in the macro pattern,and taking the cultivated land grain production capacity as the core,objectively evaluate and understand the comprehensive impact of the process of cultivated land use change on the cultivated land grain production capacity,so that can promote the scientific management and effective use of cultivated land resources to ensure that national and regional food security,and it is of great significance to seek scientific countermeasures for the use of cultivated land.This paper uses the provincial and prefecture-level cultivated land use and grain production data in China from 2009 to 2016.Based on the differences in cultivated land use ways in different regions,this paper studies the regional differences in cultivated land use by analyzing the spatial-temporal change characters of cultivated land use and the evaluation model of cultivated land grain productivity.The characteristics of change and the process of corresponding changes in grain production capacity reveal the differences and similarities between changes in cultivated land use and grain production capacity.On this basis,with the help of the elasticity coefficient and contribution rate impact analysis method,the influence relationship of cultivated land use change on grain production capacity under different spatial patterns is identified,and the regional grain production situation under the background of different cultivated land use change characteristics is analyzed.We proposed an optimized farmland utilization plan and management strategy for the use of cultivated land to maintain and enhance regional cultivated land grain production capacity.Research indicates:(1)The overall area of cultivated land use in China shows a downward trend.The characteristic of"quantity"reduction has always been the overall reflection of changes in China's cultivated land use during the period,but the internal cultivated land use types have different trends:the total area of cultivated land has decreased by46.36×10~4 hm~2 over the past 8 years,with an annual decrease of 0.04%.The dry land decreased by 81.90×10~4 hm~2,and the irrigated land and paddy fields increased by11.49×10~4 hm~2,24.05×10~4 hm~2 respectively;the increase in cultivated land area is mainly concentrated in areas with low levels of grain productivity in China.The characteristics of"quality degradation"have gradually become an important reflection of changes in China's cultivated land use.(2)China's cultivated land grain production capacity has a large regional difference.During the period,the changes in cultivated land grain production level and production capacity in different provinces and cities have similarities in time trends,but the differences in spatial distribution changes are relatively large;benefited from the increase in the yield per unit of grain,it has made up for the negative effects of food production brought about by the reduction of the cultivated land use area in China,making the overall grain production level in China steadily increase;in the analysis of regional space,the grain production capacity of cultivated land in South China,East China and other regions is relatively high,but during the period there show a certain weakening trend.The conditions for grain productivity have not been fully utilized,and the supply pressure of increasing grain production has shifted to regions with weak ecological environments such as northwest,northeast,and north China and low levels of grain productivity.(3)The elasticity analysis of the impact of changes in cultivated land use on grain production capacity in China can be divided into four areas:"double positive and increasing areas","double negative and decreasing areas","positive and negative change affecting areas"and"negative and positive change affecting areas".In the study of contribution factors,the dominant difference between intensive use and extended use of cultivated land can be further distinguished;under the current background,the“positive and negative changes”of the increase in cultivated land grain productivity and the reduction in cultivated land use area are the main types of cultivated land use in China,while the increase in grain yield and the multiple cropping mode based on intensive excavation have played an important role in ensuring China's grain output and cultivated land grain productivity level,and are also important strategies for stabilizing the existing grain productivity and further increasing the level of food production in a certain period of time.Therefore,in the process of cultivated land use,it is necessary to further deepen the understanding of the characteristics of cultivated land use change in the context of regional differences,as well as the changes in the process and dynamic characteristics of cultivated land grain productivity;scientifically analyze the impact of spatio-temporal changes in cultivated land use on grain production capacity,based on this premise,the measures should be adapted to local conditions and regionalized policies to develop farmland utilization models that are conducive to the development of cultivated land grain production capacity and regional food security supply.