Simulation and analysis on the influence of different types of soil background on the remote sensing information of wheat NDVI of farmland

It is quite confusing to effectively monitor and precisely evaluate growing conditions of wheat by using normalized differential vegetation index based on pixel size (NDVIp) as they are significantly different when acquired by the wheat of same growth status with different types of soil background. The wheat canopy normalized differential vegetation index(NDVIc) acquired by one scene of multi-spectral remote sensing image with no soil disturbance, pure black background are similar while soil backgrounds are often different. In view of this situation, based on the fixed wheat canopy spectrum which means the NDVIc is a constant value, this paper selects 9 typical soil types in our country as background in order to study the influence of different soil background types on NDVIp of wheat and analyze the sensitivity of NDVIp of wheat to the vegetation coverage simulated by diverse liner mixed ratio of wheat canopy and soil background on the remote-sensing's pixel scale. The results show that: (1)wheat NDVIp of farmland increases along with the increment of vegetation coverage under the same type of soil background, and vice versa; (2)wheat NDVIp of farmland varies greatly with different soil background types, and the difference decreases while the vegetation coverage exceeds 25%; (3) NDVIp sensitivity also shows a quite difference to vegetation coverage under the diverse soil background types. The influence of soil background on NDVIp sensitivity is the lowest when the vegetation coverage ranges from 25% to 35%.