|Butts, Christopher - Chris|
Submitted to: Agricultural Water Management
Publication Type: Peer reviewed journal
Publication Acceptance Date: 6/27/2012
Publication Date: 8/2/2012
Citation: Rowland, D., Faircloth, W., Payton, P.R., Tissue, D., Ferrell, J., Sorensen, R.B., Butts, C.L. 2012. Primed acclimation of cultivated peanut (Arachis hypogaea L.) through the use of deficit irrigation timed to crop developmental periods. Agricultural Water Management. 113:85-95. Interpretive Summary: Efficient irrigation scheduling is the primary concern for producers in water-limited regions, which now include the majority of U.S. production areas. Creative, field-based approaches are needed to address this issue. Stress “memory” or acclimation is a well-known phenomenon in plants. Recently, we incorporated the acclimation response into a regulated deficit-irrigation production model where water deficits are managed during key growth stages to induce physiological and morphology changes in the crop and save water. Here, we tested the effects of regulated deficit irrigation on crop development and yield in a large-scale peanut field trial. Our primary goal is to identify key response times for peanut in order to develop alternative irrigation schedules that maximizes peanut yield and grade while reducing water consumption. The environmental conditions, primarily precipitation patterns were dramatically different for the growing years tested and those conditions resulted in significant differences in yield between the two growing years. However, in both years, early season deficit irrigation treatments lasting 45 days showed equal or numerically greater yields than the fully irrigated controls. One possible mechanism for the early season deficit acclimation is increased root growth during this phase of development which allows for enhanced water uptake at depth during late season growth when transpirational water demand peaks. These results indicate that by using mild to moderate water stress timed to certain developmental stages has the potential to improve agronomic water-use efficiency and could be an important strategy for maintaining production in this region of the U.S. hit hard by drought and decreasing water supplies. Additional research on stress timing and more importantly, accurate measurement of stress, is needed to refine this approach.
Technical Abstract: Water-deficits and high temperatures are primary factors limiting peanut production across the U.S., either because of regional aridity or untimely rainfall events during the growing season. In the southern High Plains of west Texas and eastern New Mexico, low natural rainfall (450 mm) necessitates the use of significant irrigation in production systems. To develop irrigation schemes that maximize peanut production in this environment while reducing overall water consumption, a large-scale field experiment was established in 2005 and 2006 using differing rates of irrigation (50%, 75%, and 100% of grower applied irrigation) timed to different periods of peanut development (early, middle, and late season). The overall objective was to develop alternative irrigation schedules that maximized peanut yield and grade while reducing water consumption by timing deficits to specific crop developmental periods. Precipitation patterns and ambient temperatures showed greater stress levels in 2006 which likely reduced yields across all treatments in comparison to 2005. While yields were reduced 10% and 26% in both 2005 and 2006, respectively, in the 50% irrigation lasting full season in comparison to the fully irrigated treatment, early season drought treatments lasting 45 days in both years showed equal or numerically greater yields than the fully irrigated controls. Additional crop measurements in 2006 indicated that overall crop health was maintained as measured by NDVI in the 75% deficit treatment. Additionally, root growth was enhanced in the 50% treatment, lending evidence for possible mechanisms whereby the crop compensated for reduced water levels while being able to maintain yields in comparison to the fully irrigated treatment. These results indicate that by using mild to moderate water stress timed to certain developmental stages has the potential to improve agronomic water-use efficiency and could be an important strategy for maintaining production in this region of the U.S. hit hard by drought and decreasing water supplies.