Analysis on Spatial-temporal Changes of Cultivated Land Productivity in Jilin Province from 2000 to 2019 Based on EVI Time Series

The spatiotemporal change characteristics of cultivated land productivity (CLP) are essential to ensure regional food security and promote the sustainable use of cultivated land resources. Jilin Province is an important major grain production area and commodity grain production base in China. If the cultivated land productivity level of Jilin Province over the past 20 years can be both quickly and fully reflected, it would be helpful to discover the potential of increasing production of this area. Based on the hypothesis that the EVImax was a proxy of cultivated land productivity, the moderate resolution imaging spectroradiometer (MODIS) data with 250 m spatial resolution and 16 d temporal resolution in Google Earth Engine (GEE) platform was used to calculate CLP in Jilin Province. The coefficient of variation method was used to study the stability of cultivated land productivity. The level of CLP was explored by using the EVImax mean from 2000 to 2019, and the changing trend and amplitude of CLP was analyzed in study period by using both Theil-Sen median trend analysis and the Mann-Kendall (MK) test. The result of the trend and stability were integrated to acquire the level of CLP. Using time series remote sensing data to monitor regional crop growth and yield levels can objectively assess the productivity of cultivated land, and provide technical support for farmland construction and improvement of cultivated land quality. The results showed that the overall change amplitude was dominated by a slightly increasing trend. In cultivated land concentrated area, the change trend of productivity was better than that of broken cultivated land area in the east. The area with improvement of CLP accounted for 95.66%, mainly distributed in the central and northwestern of Jilin. The area with degradation of CLP accounted for 4.34%, mainly distributed in the southeast of Jilin or the surrounding of cities. The CLP level was generally high in the southeast and low in the northwest in cultivated land in Jilin, China. The area with the lowest productivity was located in the northwest of Jilin. The low-value areas of CLP were located in low-lying areas around towns and in low-lying areas where saline-alkali marshes were distributed in the northwest. High-value areas of CLP were concentrated in contiguous areas of farmland near rivers. In terms of the genesis of different landform types, volcanic lava landforms had the highest productivity of cultivated land, followed with flowing water landforms, wind-formed landforms and lacustrine landforms. The stability of CLP showed a trend of higher in southeast and lower in northwest. The productivity stability of paddy field was better than that of dryland and irrigated land. Therefore, the results indicated that time series remote sensing data can be used to objectively monitor the CLP. Different strategies of cultivated land protection and productivity promotion should be implemented in Jilin Province, such as stabilizing the eastern grain-producing areas, increasing the central grain production core area, and focusing on the western grain production reserve areas. © 2022, Chinese Society of Agricultural Machinery. All right reserved.