Submitted to: National Information Management and Support System
Publication Type: Other
Publication Acceptance Date: October 21, 2005
Publication Date: November 30, 2005
Repository URL: http://lgu.umd.edu/lgu_v2/pages/reportsMeet/4681_min.doc
Citation: Sassenrath, G.F., Fisher, D.K., Thomson, S.J. 2005. ("Irrigation Management for Humid and Sub-Humid Areas.") S1018 Annual Report for Mississippi-USDA Agricultural Research Service 2005. National Information Management and Support System. S1018 Multistate Research Project. p.25-27 Interpretive Summary: The S-1018 Regional Project “Irrigation Management for Humid and Sub-humid Areas” is focused on research pertaining to the timely and accurate application of irrigation for crop production in humid regions. As collaborators on the research project, scientists at the USDA-ARS Application and Production Technology Research Unit in Stoneville, MS, are undertaking research to improve the accuracy and ease of detection of the onset of water stress in crop plants. Remote sensing from ground rigs and aerial spray planes is used to determine crop health and soil moisture status. An inexpensive automated system was developed to record soil moisture measurements taken with the Watermark soil moisture sensors. Additional research is focused on developing accurate measures of crop water use. Weighing lysimeters have been installed in cotton fields, and record actual water use through the growing cycle. These measures, taken together with soil moisture and environmental conditions, are being used to develop improved irrigation scheduling methods for the crops and soils common to the region.
Technical Abstract: The overall goal of our research is the development of economically viable, environmentally sound production systems for the Mid-South. Because of the growing importance of water management to crop production in the Lower Mississippi Alluvial Flood Plain, particular emphasis is placed on addressing issues of crop water use and irrigation timing and amounts. Our principle research efforts to date are focused on the accurate detection of crop water use and plant water status, and the development of accurate irrigation scheduling guidelines for the Mid-South. Measurements of crop water status are being made with remote sensing to directly indicate crop health, and inferred from crop water use by determination of soil moisture and transpiration. Methods of irrigation scheduling commonly rely on measured soil moisture status or estimated crop water use. To improve the quantity and quality of the soil moisture data collected, an inexpensive automated system was developed that remotely and automatically collects and records Watermark soil moisture sensor measurements. To estimate crop water use, we tested an evaporation pan (the UGA EASY pan) for its suitability for scheduling irrigation of cotton in heavy clay soils. Weighing lysimeters have been installed to measure reference and crop evapotranspiration. In addition to giving accurate measurements of cotton plant water use, lysimeter measurements are used to evaluate existing evapotranspiration models under humid conditions, calibrate the models if necessary, and develop crop coefficient functions for use in the Midsouth area.