Cotton Field Drought Monitoring Models With Remotely Sensed Data In Arid Area

Cotton is the most dominant crop in XinJiang. And it's leading economic development for BingTuan.but in Xinjiang water resources is extremely shortage,moreover the contton plant in this area is relative relative, to cause water resources extremely shortage when contton in blooming stage, to create section contton field to stand drought,largely to reduce the output of cotton. as a result of practical situation this text's objective is monitoring contton field in XinJiang, to start research model and method. Furthermore preliminary to implement achieve ravages of a drought of contton field's goals, in connection with contton's characteristic, in the first place make use of several contton field moisture content method, to compare their advantage and disadvantage. Especially directed towards when contton in blooming stage, we design subdistrict test and contton field test, simultaneously we used Landset5 data to acquire accurate contton field moisture content message, make research of contton field with exploit middle resolution factor image. The following sections are included in the study.(1) measure and test contton field moisture content with several different method,and compare their advantage and disadvantage,thie text proved use canopy reflectance spectra is more accurated than other method, in different drought compel the reflectance spectra show discrepancy in 700-1300nm and it's notability in 1600-1899nm.(2) Crop water status is a key indicator for evaluating crop condition, increasing yield and improving products quality. The technology of no-destructive and rapid monitoring plant water content is required for improving management in precise cotton production. The objectives of this study were to determine the relationships between plant water content and canopy reflectance spectra in cotton, the quantitative relationships between spectral reflectance of canopy-scale cotton plants with water content of plants were studied, and the cotton plant water content estimation models with spectral parameters were developed. The purpose of non-destructive monitoring cotton plant water status was achieved. The field experiments with different irrigated levels were conducted in 2008 and 2009. The time-course measurements were taken on canopy hyperspectral reflectance and water contents of cotton plants in during the experiments period. The relationships between the hyperspectral parameters of cotton canopy and the plant water content of cotton plants were analyzed, the cotton plants water content estimation model with hyperspectral parameters were established.The plant water content of cotton showed the trend to ascend At different growth stage, the relationship of cotton plant water content and spectral reflectance in the visible band 400nm was to ascend correlated, in the near infrared 700nm range showed a to drop correlation, while in 1800nm range, the correlation is more complicated. The correlations of 11 kinds of selected spectral parameters and the plants water content were significant difference in different growth periods. Among them. the best estimation models of plants water content in different growth stages were difference. The average relative error of estimated cotton plants water content used of models withWI1/NDV1 in square stage, blooming stage. full boll stage and opening boll stage, respectively, was less than 13%. The best estimation model of cotton plants water content was used of WI1and NDVI developed models in square stage, blooming stage, full boll stage and opening boll stage, respectively.(3)This text exploit the landset5's data in July and August in 2009,based on this data to construct the NDVI-Ts space and TVDI index. Use TVDI index to evaluate cotton field's ravages of a drought, and prove relations between TVDI and top soil moisture. The relationship between TVDI and top soil moisture distinct interrelated, The relationship between NDWI and top soil mioisture was unrelated,but it's applicable in leaf water content.