2008 Annual Report
We have been developing several techniques during FY2008 for obtaining spatial NDVI information in a large-field setting in preparation for our FY2009 cotton experiment. One method collects NDVI data by active vegetation index sensors mounted on a tractor. During the past two years, we collected active sensor NDVI data that helps optimize the NDVI crop coefficient model. The main advantage of the active sensor is that it is insensitive to sun angle. This will allow NDVI measurements over the entire field during normal tractor operations without loss of data quality. A prototype 3-band radiometer was built this year as part of a wireless mesh network system. We plan to install a number of these radiometers to provide continuous NDVI data at fixed locations in the large field. Final development and testing of the unpiloted aerial vehicle will be performed by University of Arizona personnel. An improved autopilot package was installed, which will enable collection of frequent spatial NDVI data. The helicopter-based imaging system was tested over the camelina growing season with new on-board computer and monitor. The operating software was modified to improve reliability and ease of use. This system is now ready to provide remote sensing imagery during the large-field experiment, which will be used to periodically map ET for the entire field using surface energy balance modeling.
During FY2008, the CERES-Wheat plant growth model was evaluated for local conditions using experimental data from our previous wheat experiments in Maricopa. The model was evaluated for its ability to simulate plant growth responses and soil moisture conditions under varying irrigation, plant population, and nitrogen levels. Techniques were also explored for implementing the model as a real-time predictor of crop water use for irrigation scheduling.
Spectral reflectance characteristics of lesquerella canopies were evaluated during a collaborative 2008 field experiment in Maricopa. The lesquerella reflectance data are being developed to use remote sensing for identifying key growth stages and to optimize harvest schedules.
During FY2008, team scientists participated in a multi-agency remote sensing field campaign in Bushland, TX, including the planning and coordinating of field data collection. A prime objective is to validate and improve ET methodologies using remote sensing.
All of the above activities address issues within National Program 211, Water Availability and Watershed Management, Problem Area 2, Irrigation Water Management.
5.Significant Activities that Support Special Target Populations
El-Shikha, D.M., Barnes, E.M., Clarke, T.R., Hunsaker, D.J., Haberland, J.A., Pinter Jr, P.J., Waller, P.M., Thompson, T.L. 2008. Remote Sensing of Cotton Nitrogen Status Using the Canopy Chlorophyll Content Index (CCCI). Transactions of the ASABE. 51(1):73-82.
Erives, H., Fitzgerald, G.J., Clarke, T.R. 2007. Non-rigid registration of hyperspectral imagery for analysis of agronomic scenes. Biosystems Engineering. 98:267-275
French, A.N., Jacob, F., Anderson, M.C., Kustas, W.P., Timmermans, W., Gieske, A., Su, B., Su, H., McCabe, M.F., Li, F., Prueger, J.H., Brunsell, N. 2005. Surface energy fluxes with the Advanced Spaceborne Thermal Emission and Reflection radiometer (ASTER) at the Iowa 2002 SMACEX site (USA). Remote Sensing of Environment. 99:55-65. Corrigendum 99:471.
French, A.N., Hunsaker, D.J., Clarke, T.R., Fitzgerald, G.J., Luckett, W.E., Pinter, Jr., P.J. 2007. Energy balance estimation of evapotranspiration for wheat grown under variable management practices in central arizona. Transactions of the ASABE. 50(6):2059-2071
Hunsaker, D.J., Fitzgerald, G.J., French, A.N., Clarke, T.R., Ottman, M.J., Pinter, Jr., P.J. 2007. 2007. Wheat Irrigation Management Using Multispectral Crop Coefficients. II. Effects of Irrigation Scheduling on Soil Water Depletion, Grain Yield, and Water Use Efficiency. Transactions of the ASABE. 50(6):2035-2050
Inamdar, A.K., French, A.N. 2008. Land surface temperature retrieval at high spatial and temporal resolutions over the southwestern United States. Journal of Geophysical Research. 113:1-18.
Hunsaker, D.J., Fitzgerald, G.J., French, A.N., Clarke, T.R., Ottman, M.J., Pinter Jr, P.J. 2007. Wheat irrigation management using multispectral crop coefficients: crop evapotranspiration prediction. Transactions of the ASABE. 50(6):2017-2033