陕西省耕地质量时空变化特征及其分异规律

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

为从省域层面、地理区域、市域层面等3个空间尺度系统分析陕西省耕地数量和质量时空变化特征及其分异规律,以期为保护耕地资源、划定基本农田区、制定耕地质量管护对策等提供科学依据。该文基于陕西省2005—2015年长时间序列的耕地分等评价数据,采用GIS的空间分析、数理统计分析、地统计学分析等方法,结果表明:1)陕西省耕地数量在2005—2015年间整体呈下降趋势,近些年通过占补平衡及高标准农田建设,减少趋势已得到遏制,基本达到耕地数量动态平衡;2)陕西省耕地质量整体不高,平均利用等11.33;近十年来全省耕地质量总体上变化不大,但呈下降趋势;3)陕北地区作为陕西省耕地后备资源,积极开展土地整治工程,同时进行生态建设,耕地数量和质量均有所提升。该项研究成果为土地整治等耕地质量建设提供科学依据,为基本农田划定、占补平衡等耕地质量管理提供了基础支撑。

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.