Submitted to: ASABE Annual International Meeting
Publication Type: Proceedings
Publication Acceptance Date: 5/30/2008
Publication Date: 6/29/2008
Citation: French, A.N., Hunsaker, D.J., Thorp, K.R., Clarke, T.R. Estimating crop water use for camelina with remote sensing. ASABE Annual International Meeting. pp. 1-10. Interpretive Summary: A field study of Camelina Sativa was conducted in Maricopa, Arizona in 2007 and 2008 to determine effective strategies for monitoring consumptive water use for this oil seed crop. The oil from Camelina has edible and industrial uses and could be especially valuable because it may use less water than competitor crops such as Canola. Currently little is known about how much, and when to water Camelina in arid lands such as central Arizona. Experimental results from the 2007-8 studies show that crop water use, and its spatial variability, can be accurately estimated by using remotely sensed surface temperatures. Analyses of these estimates suggest that Camelina can tolerate different irrigation schedules with minimal yield penalty. These results are important for farmers in arid regions such as central Arizona who are considering growing Camelina.
Technical Abstract: Camelina (Camelina sativa [L.] Crtz.) is an oilseed crop with apparently low water requirements and therefore could be very attractive for growers in arid lands. Verifying this potential for environments such as the U.S. Southwest, however, requires field experiments that test yield response to different irrigation schedules. By adapting evapotranspiration (ET) methodologies previously developed for more conventional crops (i.e., wheat and cotton), consumption of water by Camelina could be assessed in a spatial context. Using remote sensing observations collected in 2007 and 2008 over a 1.3 ha plot in Maricopa, Arizona, daily ET over Camelina was estimated with a surface energy balance approach. The observations included ground-based imagery spanning visible, near infrared, and thermal infrared wavelengths. Crop treatments included four level of water depletion for 32 plots and one level of water-stress for 6 other plots. Modeled transpiration generally agreed well with independently obtained soil moisture depletions. Preliminary results indicate that crop coefficients, adapted by vegetation indices, provide sufficient guidance for effective irrigation scheduling and that canopy surface temperature changes can be a reliable indicator of ET.