粮食安全视角下河南省淮河流域耕地资源时空演变

Spatial-Temporal Evolution of Cultivated Land Resources in Huai River Basin of Henan Province from the Perspective of Food Security

为掌握粮食安全背景下耕地资源时空变化特征,加强耕地资源保护,基于多时间节点遥感数据和km网格评价单元,系统分析了河南省淮河流域1990—2018年3个时间段内耕地资源变化强度、类型及热点区域的格局特征。结果表明:(1)河南省淮河流域1990—2018年耕地面积减少约831.01 km 2,减少幅度达5.75%,其中,1990—2000年有小幅度增加,2000—2010年减少837.68 km 2,2010—2018年减少57.52 km 2,粮食主产区耕地数量持续减少引发的粮食安全保障问题引起政府和学术界的高度关注,保证耕地数量不减少是保障区域粮食安全的根本措施;(2)耕地资源变化主要受国家政策(如退耕还林)和市场价格(旱改水)影响,呈变化强度大、范围广的特征,2000—2010年部分地区变化强度35.00%~100.00%,变化类型以建设用地扩张对耕地的占用为主,其次为耕地内部水田、旱地之间的相互转化以及退耕还林等,建设用地扩张与耕地保护矛盾突出。(3)不同时间段内耕地资源变化热点区差异较大,由1990—2000年的面积小且分散,到2000—2010年的集中片状分布,再到2010—2018年的整体向西北正阳县转移,地方性特征明显。研究将为坚守耕地粮食安全底线,制定防止耕地“非农化”、“非粮化”、保持耕地稳定性等调控和管制措施提供决策支撑。

We systematically analyzed the characters of cultivated land resource change intensity,type and hot spots in Huai River Basin of Henan Province in 3 periods from 1990 to 2018 in order to master the temporal and spatial variation characteristics of cultivated land resources in the context of food security and strengthen its protection based on multi-temporal remote sensing data and kilometer grid evaluation unit.The results show that:(1)the cultivated land had been totally reduced by 831.01 km 2 from 1990 to 2018,with a decrease rate of 5.75%in Huai River Basin of He′nan Province;actually,slightly increased in 1990—2000,decreased by 837.68 km 2 from 2000 to 2010,and decreased by 57.52 km 2 from 2010 to 2018;the problem of food security caused by the continuous decrease of cultivated land in this major grain-producing area has attracted the attention of the government and academic circles,and maintaining a certain acreage of cultivated land will be the fundamental to ensure the food security;(2)influenced by national policies,such as green for grain,and the market price(the huge conversion of dry fields to paddy land driven by higher price of rice than corn),the changes of cultivated land resources were characterized by large intensity and wide range,for example,the change intensity in some area was between 35.00%and 100.00%from 2000 to 2010;the main feature of the change type was that the huge part of cultivated land was transferred into construction land,which made the situation of farmland protection more and more urgent,followed by the interactive transforms between dry fields and paddy land,cultivated land and forestland;(3)the change hotspots of cultivated land resources varied greatly in different periods,small and scattered change occurred during 1990 and 2000,concentrated and patchy distribution occurred during 2000 and 2010,and then shifting to Zhengyang County in the northwest occurred during 2010 and 2018,appearing the obvious local characteristics.Generally,this study could provide decision support for upholding the bottom line of food security,formulating regulation and control measures such as preventing the‘non-agricultural’and‘non-grain’behaviors,and maintaining the stability of cultivated land resources.