覆膜种植对玉米生长初期NDVI识别的影响

Impacts of film mulch planting on NDVI identification in corn early growth

覆膜种植是干旱区绿洲农业普遍采用的方式,大面积覆膜种植对农作物早期NDVI生长状况监测具有较大的影响。本文在张掖绿洲以大面积种植的玉米为测定对象,选择黑膜和透明膜覆盖与裸地种植进行地面反射光谱特征研究,揭示覆膜种植对玉米生长初期NDVI识别的影响。结果表明：黑膜和透明膜与裸地之间的光谱反射率都存在显著差异（P〈0.05）;在325-1035 nm波段波长范围内,黑膜、透明膜、裸地光谱反射率平均值总体特征为透明膜（25.9%）〉裸地（13.9%）〉黑膜（13.7%）;对使用较多的Landsat和MODIS数据而言,覆膜率与NDVI之间呈线性回归,其中透明膜覆盖率与NDVI的线性趋势回归斜率大于黑膜覆盖度;地膜覆盖种植对玉米早期生长NDVI识别有较大的影响。

Film mulch planting is commonly adopted in oasis agriculture in arid zone, and largescale film mulch cultivation may have significant effects on the remote sensing monitoring for NDVI of crop’s early growth. In order to better understand spectral reflectance characteristics of different mulch materials, this study employed black film and transparent film, compared with bare cropland, to illustrate the impact of film mulch planting on NDVI identification in corn’s early growth. The results showed that the spectral reflectance among black film, transparent film and bare cropland existed significant difference （P〈0.05）. At 325-1035 nm wavelength, the average spectral reflectance of transparent film, bare cropland and black film were 25.9%, 13.9% and 13.7%, respectively. For Landsat and MODIS data, relationship between the mulching area and NDVI was linear in largescale film mulch cultivation area, and the slope of the regression equation of the transparent film was larger than that of the black film. These results indicated that the mulch film planting had significant influence on identifying the corn’s early growth based on NDVI monitoring.