Location: Soil and Water Management ResearchTitle: A three-dimensional index for characterizing crop water stress Author
Submitted to: Remote Sensing
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/15/2014
Publication Date: 5/2/2014
Citation: Torrion, J.A., Maas, S.J., Guo, W., Bordovsky, J.P., Cranmer, A.M. 2014. A three-dimensional index for characterizing crop water stress. Remote Sensing. 6:4025-4042. Interpretive Summary:
Technical Abstract: The application of remotely sensed estimates of canopy minus air temperature (Delta Temp) for detecting crop water stress can be limited in semi-arid regions, because of the lack of full ground cover at water-critical crop stages. Thus, soil background may restrict water stress interpretation by thermal remote sensing. For partial ground cover, the combination of plant canopy temperature and surrounding soil temperature in an image pixel is expressed as surface temperature. Soil brightness for an image scene varies with surface soil moisture. This study evaluates soil brightness, ground cover and Delta Temp and determines a fusion approach to assess crop water stress. The study was conducted (2007 and 2008) on a commercial scale, center pivot irrigated research site in the Texas High Plains. High-resolution aircraft-based imagery (red, near-infrared and thermal) was acquired on clear days. The ground cover and soil brightness were derived using the Perpendicular Vegetation Index approach. The Delta Temp was derived using an array of ground surface temperature sensors, thermal imagery and weather station air temperature. The Delta Temp, ground cover and soil brightness were fused using the hue, saturation, intensity method, respectively. Results showed that this method can be used to assess water stress in reference to the differential irrigation plots and corresponding yield without the use of additional energy balance calculation for water stress in partial ground cover conditions.