Identification of water stress effects on cotton crops using remote sensing

Abstract

The average demand of cotton in Colombia from 2006 has fallen from 80 000 tons / year to 30 000, this appears for the strong climate changes, where there meets reflected the bad quality of the fiber of spinning. In this work has identified the effects of the water stress of the cotton crop in the Municipality Villavieja, Huila. With the implementation of 12 images satellites, it was possible to observe the effects of the water stress, the series Landsat 4 TM, 5 TM and 7 ETM+ were implemented with epochs understood by the climatic periods of Colombia (dry and humid). The images were processed in the software Erdas Imagine 9.2, different transformations were applied to them: radiance, reflectance, Normalized Difference Vegetation Index and Normalized Difference Water Index, to finally calculate the Normalized Differential Drought Index. Also applied the Crop Water Stress Index (CWSI) with information of superficial temperature. The validation gave like proved a correlation of R2  = 0.9271 and 0.4757 for dry and humid season, respectively. The Index CWSI has demonstrated to be useful in the programming irrigation. When the threshold value is determinate in the different phenological stages of the crops, it is used to avoid hurts for water stress and decrease in the production of the crops.