Monitoring Spectral Characteristics Change And Plant Nitrogen Content Of Irrigation-land And Dry-land Winter Wheat

The experiment took planting area of winter wheat in Shanxi Province Wenxi County as subject to study the monitored effect of remote sensing. Based on field survey, winter wheat canopy reflectivity, chlorophyll content, carotenoid content, leaf area index and plant nitrogen content was determined, vegetation index was calculated. Then according to the technology path of spectrum parameters-agronomy parameters-nitrogen content, forecast model of nitrogen content monitoring at irrigable-land and dry-land was established. Results showed that:1. At irrigable-land and dry-land, winter wheat had the similar tendency of canopy spectral reflectivity during the whole growth period. There was an obvious reflection peak near550nm, the reflectance was rapidly rising during650-750nm, the curve change was obvious and reflectance values were high during750-1350nm. An obvious peak of the first derivative of the reflectance was in the red edge position. From jointing stage to maturity stage, peak of the original canopy spectral curve and the first derivative of the spectral curve reflection gradually becomes obvious.2. At different growth stages of irrigable-land and dry-land, winter wheat leaf pigment content, LAI and nitrogen content changed consistency that was "low-high-low "trend. Winter wheat chlorophyll and carotenoid content of dry-land was higher than that of irrigable-land, LAI and nitrogen content of irrigable-land was higher than that of dry-land.3. In jointing stage, there was significant correlation between chlorophyll content and FDNDVI (685,1003), carotenoid content and FDNDVI (1308,642), LAI and FDDVI (771,685) at dry-land; at irrigable-land there was significant correlation between chlorophyll content and FDDVI(1082,624) FDMSAVI(1082,624), carotenoid content and FDDVI(1082,624) FDMSAVI(1082,624), LAI and FDNDVI(770,688). In heading stage, there was significant correlation between chlorophyll content and FDMSAVI(1156,639), carotenoid content and FDDVI(1164,691) FDMSAVI(1164,691), LAI and FDDVI(762,697) at dry-land; at irrigable-land there was significant correlation between chlorophyll content and FDDVI(787,648) FDMSAVI(787,648), carotenoid content and FDDVI(819,648) FDMSAVI(819,648), LAI and FDDVI(1036,628) FDMSAVI(1036,628). In filling stage, there was significant correlation between chlorophyll content and FDDVI(950,755) FDMSAVI(950,755), carotenoid content and FDDVI(951,746) FDMSAVI(951,746), LAI and FDDVI(966,755) FDMSAVI(966,755) at dry-land; at irrigable-land there was significant correlation between chlorophyll content and FDRVI(1091,682), carotenoid content and FDMSAVI(1073,605), LAI and FDDVI(750,606) FDMSAVI(750,606).4. In addition to LAI of the filling stage and nitrogen content of the dry land was not related, agronomic parameters of each growth stage and nitrogen content was significant correlation.5. The connection point of the plant nitrogen content spectrum monitoring model was agronomic parameters, the best agronomic parameter was chlorophyll at each growth stage. The best arguments of dry-land were FDNDVI(685,1003), FDDVI(1156,639), FDMSAVI(950,755), the best arguments of irrigable-land were FDMSAVI(1082,624), FDMSAVI(787,648), FDRVI(1091,682).