Spatial and temporal changes and its variation of cultivated land quality in Shaanxi Province

The maintenance of high-quality cultivated land is of fundamental and strategic significance to ensure national food security and maintain social stability. To provide a scientific basis for conserving cultivated land resources, basic farmland protection and cultivated land monitoring, taking Shaanxi Province in northwest China as an example, based on the database of cultivated land grade in Shaanxi Province from 2005 to 2015, the spatial and temporal changes of cultivated land quality in Shaanxi Province were analyzed at 3 spatial scales: the provincial level, the geographical area level and the urban level. This research used a combination of methods including spatial analysis, statistical analysis and geo-statistical analysis. Production capacity was the basic measure of cultivated land quality and the land use coefficients reflected the extent to which human production explored the natural potential. The utilization grade, which was calculated from the land use coefficient, reflected the productivity of cultivated land under the average actual inputs and technical conditions in various regions. The data analysis in this paper was based on the utilization grade, which was a closer reflection of the actual level of land output. The results showed: 1) The area of cultivated land in Shaanxi Province decreased by 0.22% in the period from 2005 to 2015. The trend of decline has been stabilized in recent years, which basically reaches the balance of cultivated land. The decline of cultivated land was partly for ecological purposes and partly for construction purposes. The area used for ecological restoration was 77938 hm2, from 2005 to 2015. Since 2010, some measures have been implemented to increase the quantity of cultivated land, including preventing the further loss of cultivated land, land reclamation and ecological construction. 2) The average grade of cultivated land quality in Shaanxi Province was 11.33 in 2015, which was not good, and the quality of cultivated land in the province did not change significantly over the past 10 years. The area of excellent-, high-and low-grade land decreased and middle-grade land area increased. The decline in high-grade land area was because urban construction occupied a large amount of high-quality cultivated land. The quality of supplementary cultivated land was low, which resulted in the overall decline of cultivated land quality. Central Shaanxi had a higher quality of cultivated land because it was located on a plain, and the economic, climate and other conditions were relatively good. Therefore, the location quotient of excellent-grade and high-grade land was above the provincial average. The north of Shaanxi had a lower quality of cultivated land because the climate was drier, and the soil was poor. However, the location quotient was stable. 3) Over time the changes in the quality of cultivated land in north Shaanxi, central Shaanxi and south Shaanxi increased, decreased and were stable, respectively. The north of Shaanxi actively carried out land reclamation and ecological civilization construction, resulting in a cultivated land quality grade of 13.35 by the end of the study period. Therefore, both the quantity and the quality of cultivated land in the north of Shaanxi increased. This research provides a scientific basis for the classification and management of cultivated land quality. The area of cultivated land is stable by the end of the study, but the high-grade regions should undertake land consolidation, especially in central Shaanxi. © 2018, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.