宁南黄土丘陵沟壑区土地类型与土地利用耦合分析

Coupling analysis of land type and land use in Ningnan hilly-gully area

宁南山区是我国主要贫困片区之一,经过多年退耕还林(草)、生态移民和城镇化建设,需要进一步调整土地利用.通过高分遥感影像,解译宁南山区固原市土地类型和土地利用现状,分析了二者的耦合关系.结果表明:易于从事粮食作物生产的河川地、沟台地、塬地、壕掌地和梯田总面积3 696.31km^2,占全市国土面积的35.14%,该5种土地类型中,耕地2 984.88km^2,占这5种土地类型总面积的71.76%,占固原市总耕地面积的80.75%;需要坡改梯或采取其他水土保持措施后作为耕地的梁峁和土石丘陵缓坡地面积1 574.84km^2,占国土面积的14.96%,其中耕地面积485.73km^2.难以从事粮食作物生产的梁峁陡坡地、梁峁坬地、沟坡地、土石质丘陵陡坡地、土石丘陵坬地、石质山地总面积5 115.4km^2,占国土面积的48.61%,这6种土地类型中耕地总面积1 160.23km^2,占宁南山区固原市耕地面积的11.02%.在耦合分析的基础上,指出了土地利用调整潜在面积和需要进行生态保护的土地类型、面积及空间分布,为产业结构调整、精准扶贫和生态保护提供科学依据.

Ningnan hilly-gully region(10 524.38 km^2)in southern Ningxia Hui Autonomous Region is one of the most impoverished areas in China.After years of gain due to green project,ecological migration and urbanization,it is necessary to further adjust land use.Coupling relationship between land type and land use in Ningnan hilly-gully area was analyzed with data from high-resolution remote sensing images and DEM in 2016.The total easy farming area was found to be composed of lower river terrace land,higher river terrace land,tableland,flat hill slope land and terraced field(3 696.31 km^2),accounting for 35.14%of the total land of Ningnan hilly-gully area.Cultivated land was 2 984.88 km^2,accounting for 71.76%of total land of the above 5 types of easy tillage land types,which accounted for 80.75%of the total cultivated land of Ningnan area.The total area of moderate hill slope(slope degree≤15°)land and moderate earth-rock hill slope land(slope degree≤15°)was 1 574.84 km^2,accounting for 14.96%of Ningnan region,among which 485.73 km^2 was cultivated but prone to soil erosion and further land degradation.This 485.73 km^2 cultivated land should be changed to other land use unless proper conservation measures are adopted.The total area of steep hill slope land(slope degree 15-25°),extremely steep hill slope(slope degree>25°),gully slope land(slope degree>25°),steep earth-rock slope land(slope 15-25°),extremely steep earth-rock slope land(slope>25°)and rocky mountain land was 5 115.4 km^2,accounting for 48.61%of the total area of Ningnan region.Cultivated land on these 5 land types was 1 160.23 km^2,accounting for 11.02%of total cultivated land in Ningnan region.Cultivated land on steep hill slope and steep earth-rock slope should be completely changed into grassland or for reforestation,unless artificial terrace is build,and those cultivated land on extremely steep hill slope land,extremely steep earth-rock slope land,gully slope land,and rocky mountain land should be completely changed into grassland or for reforestation.With the help of GIS technology,the location of different land uses on all the land types were located and mapped.Data of this study can serve as sufficient base for accurate poverty lifting program,and for land use and resource protection planning.