2017-2021年景泰县耕地撂荒空间分布变化研究

Study on Spatial Distribution of Abandoned Farmland in Jingtai County from 2017 to 2021

本文基于GEE平台和景泰县2014-2016年的Landsat8 OLI影像数据、2017-2021年的Sentinel-2 MSI影像数据,计算NDVI、NDBI、MNDWI、海拔、坡度等指数特征,进行土地利用类型分类;根据撂荒地判别规则、研究区作物熟制及耕作规则对研究区近五年撂荒地进行提取,从而分析2017-2021年景泰县耕地撂荒空间分布变化特点。结果表明,(1)2014-2021年景泰县各年份土地利用类型分类结果的解译精度较稳定,总体分类精度均在0.91以上,Kappa系数均在0.89以上,表明分类结果与实际地类的一致程度较高,整体分类效果较好。(2)2017-2021年景泰县耕地的撂荒现象整体上呈波动下降的趋势。其中,2017年耕地撂荒最严重,即2017年(9560.92 hm^(2))>2021年(6849.39 hm^(2))>2019年(3120.17 hm^(2))>2018年(2970.64 hm^(2))>2020年(1222.61 hm^(2))。(3)研究区东部地区的撂荒现象相较于研究区内其他地区的撂荒现象较少,主要原因是景泰县地势西南高、东北低,且山峦丘陵占县域面积较大。

In this paper,based on GEE platform and Landsat8 OLI image data from 2014 to 2016 and Sentinel-2 MSI image data from 2017 to 2021 in Jingtai County,we calculate NDVI,NDBI,MNDWI,elevation,slope and other index features to classify land use types;extract the abandoned land in the study area in the past five years according to the abandoned land discriminatory rules,crop maturity and tillage rules in the study area,so as to analyze the spatial distribution change characteristics of cultivated land abandonment in Jingtai County from 2017-2021.The results show that,(1)the decoding accuracy of land use type classification results in Jingtai County for each year from 2014 to 2021 is stable,the overall classification accuracy is above 0.91 and the kappa coefficient is above 0.89,indicating that the classification results are consistent with the actual land types to a high degree and the overall classification effect is good.(2)The overall trend of the abandonment of arable land in Jingtai County from 2017 to 2021 is fluctuating and decreasing.Among them,the most serious abandonment of arable land in 2017,i.e.2017(9560.92 hm^(2))>2021(6849.39 hm^(2))>2019(3120.17 hm^(2))>2018(2970.64 hm^(2))>2020(1222.61 hm^(2)).(3)The abandonment of land in the eastern part of the study area was less compared to the abandonment of land in other areas of the study area.The main reason is that the topography of Jingtai County is high in the southwest and low in the northeast,and the mountains and hills occupy a larger area of the county.