Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: September 24, 2005
Publication Date: September 28, 2005
Citation: Wanjura, D.F., Mahan, J.R., Upchurch, D.R., Burke, J.J. 2005. Adapting the BIOTIC protocol to manage water deficits[abstract]. InterDrought-II: The 2nd International Conference on Integrated Approaches to Sustain and Improve Plant Production Under Drought Stress. Paper No. 3.74. Technical Abstract: The use of subsurface drip irrigation continues to increase as ground water from the Ogallala aquifer declines in the Southern Great Plains region of the USA. Yield response of cotton to limited irrigation using crop canopy temperature as the water stress signal was evaluated in a 3-year field study. They study’s objective was to control subsurface drip irrigation in the deficit water application range, evaluate the stability of irrigation control across years, and measure crop performance. Multiple time thresholds, representing different levels of stress time, were used in BIOTIC protocol for scheduling irrigation applications. Irrigation decisions were made daily and a constant irrigation amount was applied in response to irrigation signals in all time thresholds. Rain was automatically incorporated into the water input to maximize irrigation efficiency. The entire spectrum of annual rain amounts during the past 93 years was represented by the rains received in 2002, 2003 and 2004 (ranking 50th, 5th and 92nd, respectively). Particular emphasis was given to documenting the stability of irrigation and total water input among years by each time threshold. The performance of the automated irrigation system will be discussed emphasizing the stability of irrigation control, crop stress times yield versus water input, and the contribution of rain to total water input for the different deficit water levels. The time thresholds responded to environmental difference among years by applying different amounts of irrigation; however, the relationship of the deficit irrigation amounts produced was consistent. This automated system provided accurate control of irrigation input without the requirement of daily irrigation decisions by the3 crop manager.