陕西渭北旱塬区县域耕地时空变化及其对粮食生产影响

Temporal and spatial changes of cultivated land and its impact on grain production inWeibei dryland district of Shaanxi Province

耕地资源是国家粮食安全的根本保障,掌握耕地数量与质量状况是合理利用区域耕地资源的前提。以位于陕西渭北旱塬东部的韩城市为研究区域,运用GIS空间分析技术,结合耕地质量评价模型、区位指数模型与重心迁移模型,分析韩城市2009—2018年耕地时空变化及其对粮食生产的影响。结果表明:(1)2009—2018年研究区耕地空间分布变化不明显,耕地重心主要在东部平原区,耕地数量呈现西少东多、自东南向西北分散的分布格局。(2)减少耕地主要分布于龙门镇中部、新城与西庄镇交界处、金城东部和芝川镇东部,耕地减少主要原因包括城镇化进程加快、政策实施与农业产业结构调整。(3)10 a间各耕地质量等级面积两极分化且变化明显,高多低少,各级耕地均向更高级耕地转移,以中等地转为高等地最显著。(4)耕地质量区域性显著,质量等级自东部黄河沿岸向西北方向逐渐降低,以黄河沿岸与平原区为主,自上而下呈低等地-高等地-中等地三段式。(5)研究区耕地数量减少引起粮食产量下降,耕地质量分布格局影响粮食生产区位,小麦、玉米生产区与中、高质量耕地分布区重合,分布重心迁移方向一致。

This paper investigates the temporal and spatial change of cultivated land quantity,evaluation of the cultivated land quality and its temporal and spatial changes,and impact of cultivated land change on food production in Hancheng City,Shaanxi Province,China.The scope of the cultivated land is extracted using the spatial analysis method,and the change in the cultivated land quantity in Hancheng City during the study period is analyzed.The comprehensive index of the cultivated land quality is calculated using the analytic hierarchy process and Delphi method.Then,the cultivated land quality grade is conducted to obtain the evaluation results of the cultivated land quality in Hancheng City.Based on the ArcGIS software and location index model of cultivated land quality grade,the temporal and spatial changes in cultivated land quality in Hancheng City in the past decade were obtained.Finally,through the transfer model of the distribution center of gravity,the distribution center of cultivated land quality and the distribution center of grain production location in Hancheng City are calculated,and the relationship between them is analyzed.The results are as follows.(1)In the past decade,the spatial distribution of cultivated land resources in the study area has been unchanged,concentrated in the eastern plains and along the Yellow River.The amount of cultivated land gradually decreases and disperses from east to northwest,and the reduced cultivated land is distributed in the main construction areas of the central urban area.(2)The cultivated land quality in the study area changed significantly,the area of each grade varied greatly,and the area of grade 2 cultivated land accounted for the largest proportion.In space,the cultivated land quality gradually decreases from the east along the Yellow River to the northwest,and a cultivated land quality belt of low land,high land,and medium land is formed from top to bottom.(3)Farming methods,non-grain,and cultivated land quality are the main factors influencing grain yield and production location in the study area.The center of the gravity distribution area of medium and high-quality cultivated land in the study area has a high degree of congruence with the core area of wheat and corn production,and the migration direction is the same.Exploring and analyzing the temporal and spatial variation characteristics of cultivated land quality and its impact on grain production is essential to solving the problems of regional cultivated land protection and non-grain.This paper selects a typical county research area to investigate the relationship between cultivated land quality and food production from the spatial aspect,which is expressed through the spatial layout and migration direction,to reflect the cultivated land and food security in ecologically fragile areas of non-food producing areas.It is essential to deeply understand the utilization characteristics of regional cultivated land resources,make rational use and efficient management of cultivated land resources,and ensure regional food security.