Temporal And Spatial Patterns Of Differences Between The Actual And Potential Multiple Cropping Of Cultivated Land In China Under The Background Of Climate Change

Since the 21st century,the population has continued to grow in China.With limited arable land resources,food security issues have become increasingly prominent.The Multiple cropping can significantly increase food production and promote the development of agricultural economy,which is important for Chinese agricultural development and food security.Firstly,this paper constructs the NDVI time series curve by using SPOT/VNGT's NDVI data;Secondly,it uses the secondary difference algorithm to extract the information of multiple cropping index in China;and then used the agricultural ecological area(AEZ)model to simulate potential multiple cropping index with annual average climate data.On this basis,the temporal and spatial changes of the actual and potential cropping and their differences were studied respectively,and explored the current situation and changes of potential increment multiple cropping in China.The main conclusions are:(1)Chinese cultivation system from the north to the south of China and from the West to East of China all show a transition from the single-cropping system to the multi-cropping system in real and potential scenarios,and the multiple cropping index gradually increased.Single cropping system is relatively large in reality,but triple cropping system is relatively large in the simulation.(2)From 2000 to 2015,30.93%of cultivated land cropping systems in our country changed,of which 18.13%of cultivated land multiple cropping index increased and multiple cropping index increased 3.63%.The main change of cropping system occurred in the Sichuan basin region,region of the Huang-Huai-Hai plain and region of the Yangtze River.(3)From 1980 to 2015,the potential multiple cropping index increased by 14.12%and 6.88%respectively under the irrigated and rain-fed scenario in China.The basic changed characteristics of potential multiple cropping were that the area of the single and double cropping system decreased,while the triple cropping system areas increased.During the study period,the PMCI gap between rain-fed and irrigated scenarios increased from 17.32%to 24.56%,indicating that the water supply restrictions have increased significantly under the rain-fed scenario.In addition,the changes of potential multiple cropping system show great heterogeneity in the spatial pattern under the background of climate change in China.(4)From 2000 to 2015,the potential increment multiple cropping is huge in China.In 2000,the annual average planting area of arable land could increase by 49.61%to 67.35%.The largest area of increase all were region of the Yangtze River under the irrigated and rain-fed scenario.In 2015,the annual average planting area of arable land could increase by 47.90%-67.99%.The largest area of increase was region of the Yangtze River under the irrigated scenario and southern region under the rain-fed scenario.(5)From 2000 to 2015,the potential increment multiple cropping of the vast majority of agricultural areas has become larger under the irrigated scenario,and the utilization of climate resources by crops needs to be further improved.The situation is just the opposite under the rain-fed scenario,and the current agricultural planting system is actively changing from low cropping system to high cropping system.