河套灌区地下水埋深与土壤盐分对增强型植被指数的联合影响

Combined effects of groundwater depth and soil salinization on enhanced vegetation index in Hetao irrigation area

为研究干旱半干旱地区地下水埋深与土壤盐分对作物生长的联合影响,以河套灌区解放闸灌域主要种植作物(小麦、玉米、葵花)为研究对象,利用遥感影像提取增强型植被指数,野外试验获取0~20、0~40 cm土层土壤含盐量及地下水埋深数据,构建双因素坐标系确定地下水埋深和土壤含盐量对植被指数的联合响应,统计得出适宜作物生长的土壤含盐量及地下水埋深范围,研究结果表明:(1)5—6月小麦生长地下水埋深最适宜的范围分别为0.99~2.01、1.03~1.54 m,其对应的土壤含盐量分别为1.00~1.30、1.53~2.02 g·kg^(-1);(2)6—8月玉米生长地下水埋深最适宜的范围分别为1.56~1.80、1.82~2.00、1.43~2.31 m;其对应的土壤含盐量分别为1.24~1.68、1.25~1.55、0.98~1.40 g·kg^(-1);(3)7—8月葵花生长地下水埋深最适宜的范围分别为0.75~1.70、1.20~1.61 m,其对应的土壤含盐量分别为1.46~1.70、5.55~5.84 g·kg^(-1)。

To study the combined effects of groundwater depth and soil salinity on crop growth in arid and semi-arid regions,the main crops of wheat,maize and sunflower in Jiefangzha irrigation area of Hetao irrigation district were taken as the research objects in this study.The enhanced vegetation index was extracted by using remote sensing images.The data of soil salinity and groundwater depth in 0~20 cm and 0~40 cm soil layers were obtained by field experiments.The dual-factor coordinate system was constructed to determine the combined response of groundwater depth and soil salinity to vegetation index.The soil salinity and groundwater depth range suitable for crop growth were obtained by statistics.The results showed that:(1)The most suitable ranges of groundwater depth for wheat growth in May and June were 0.99~2.01 m and 1.03~1.54 m,respectively,and the corresponding soil salinities were 1.00~1.30 g·kg^(-1) and 1.53~2.02 g·kg^(-1),respectively.(2)The most suitable groundwater depths for maize growth in June,July and August were 1.56~1.80,1.82~2.00 m and 1.43~2.31 m,respectively,and the corresponding soil salinities were 1.24~1.68,1.25~1.55,0.98~1.40 g·kg^(-1),respectively.(3)The most suitable ranges of groundwater depth for sunflower growth in July and August were 0.75~1.70 m and 1.20~1.61 m,respectively.The corresponding soil salinities were 1.46~1.70 g·kg^(-1)and 5.55~5.84 g·kg^(-1),respectively.