1a. Objectives (from AD-416):
Objective 1: Optimize production systems for irrigated cotton, corn, soybean, and rice to improve water use efficiency under variable weather conditions while considering the constraints of timing for field operations, a limited growing season, and increasingly limited water supplies. 1a: Refine irrigation scheduling recommendations for aerobic rice. 1b: Determine crop canopy traits associated with improved drought tolerance in soybean. 1c: Determine the impact of cover crop in a furrow irrigated, minimum tillage, cotton/corn rotation. Objective 2: Evaluate the suitability of variable-rate center pivot irrigation for crop production on variable soils and in varying weather conditions to determine potential costs and benefits for producers. 2a: Evaluate the potential use of the ARS Irrigation Scheduling and Supervisory Control and Data Acquisition System (ISSCADA) for variable-rate irrigation management of cotton in the sub-humid U.S. Mid-South. 2b: Determine the spatial variability of crop coefficient in a cotton field. Objective 3: Evaluate the quality of runoff from irrigated cropland to determine current and potential environmental risks and develop guidelines and BMPs to reduce impact of irrigated agriculture on water quality degradation. 3a: Determine nutrient content of runoff from a surface irrigated cotton field in the lower Mississippi River basin.
1b. Approach (from AD-416):
Our interdisciplinary team will evaluate systems for irrigated crop production to address key knowledge and technology gaps limiting water use efficiency (WUE) in humid and sub-humid climates where water was generally inexpensive and often considered unlimited. We will conduct field research that incorporates spatial soil, crop, and yield data to develop approaches to optimize production systems to better respond to large spatial and temporal variations in weather that are expected to increase with climate change. We will develop recommendations that take into consideration the constraints of limited timing for field operations, marginal growing seasons for cotton and rice, and water supplies facing increased scrutiny for waste and contamination. We will develop and test methods for improved management of variable-rate center pivot irrigation technology for variable crops, soils, and weather conditions to increase potential benefits for producers. We will also evaluate the quality of runoff from irrigated cropland to determine potential environmental risks and develop guidelines and BMPs to reduce water quality degradation associated with irrigated agriculture.
3. Progress Report:
Project Number 5070-13610-007-00D was initiated during FY17. It includes objectives from Agricultural Research Service (ARS) and a Non-Assistance Cooperative Agreement (NACA) with university cooperators. Under ARS leadership: (1) Identified and obtained seed of appropriate soybean genotypes for drought and flood tolerance studies; initiated studies. (2) Collaborated with ARS scientists in Bushland, Texas, Florence, South Carolina, and Stoneville, Mississippi, to test ARS-developed system for variable rate irrigation (VRI) management. Presented article relating observed soil and plant properties at 7th Asian-Australasian Conference on Precision Agriculture. Planted study and installed sensors for crop canopy temperature and soil moisture measurement for 2018 growing season. Continued collecting data on in-season changes in soil properties in the field in conjunction with the Research Unit’s NP216 project; prepared and presented article on previous year’s results at 14th International Conference on Precision Agriculture. Collaborated with university colleague to collect data within the study field using an unmanned aerial vehicle (UAV); prepared and presented article on previous year’s results at 2018 American Society of Agricultural and Biological Engineers Annual International Meeting and expanded for submission to journal. (3) Continued observations to determine the spatial variability of crop coefficient in a cotton field to improve VRI management. (4) Because the studies in this project rely on yield monitor data for harvest results, studies on yield monitor performance have been included. An article on the influence of variety on cotton yield monitor performance using harvest data provided by producers was prepared and presented at 14th International Conference on Precision Agriculture. Multiple years’ data will be combined for submission to a journal. (5) Obtained measurements of spatially referenced cotton canopy properties in ongoing studies of irrigation practice and cultivar effects. Through a Non Assistance Cooperative Agreement with the University of Missouri (MU) (5070-13610-007-01S): (1) Maintained three real-time weather stations at research facilities in southeast Missouri with web access to the information as part of the Missouri Mesonet. (2) Continued tests using VRI to evaluate irrigation treatments for center pivot irrigated rice, corn, cotton, and soybean based on evapotranspiration calculated from on-site weather station data; continued to refine smart phone app for scheduling irrigation and continued field testing on several farms. (3) Continued study to evaluate effectiveness of controlled release nitrogen (CRN) fertilizers relative to traditional nitrogen programs for furrow irrigated cotton. (4) Continued long-term study of effect of cover crops and reduced tillage on irrigated corn and cotton. (5) Refined guidelines for preparing VRI prescriptions to avoid runoff, expanded to include aerial and satellite based prescriptions. Began field demonstration with corn.
1. Investigated suitability of atmometers to estimate reference evapotranspiration in a humid region. The Missouri Crop Water Use application was developed to aid farmers in choosing the appropriate time to apply irrigation. It accesses reference evapotranspiration data from the Missouri Mesonet; therefore only locations near network weather stations can be managed using the application. ARS researchers in Portageville, Missouri, and university collaborators investigated the suitability of atmometers, which have successfully estimated evapotranspiration in arid regions, as an inexpensive alternative to electronic weather stations in humid areas. Atmometer estimates were compared to electronic weather station calculations in multiple Missouri Mesonet locations over two years. A close relationship was observed; however, atmometer values were consistently lower, suggesting that additional calibration may be required for irrigation scheduling in humid regions. Improving evapotranspiration estimates will allow farmers throughout the world to irrigate their crops more efficiently, ensuring a stable supply of food, feed, and fiber.
Straatmann, Z., Steven, G., Vories, E.D., Guinan, P., Travlos, J., Rhine, M. 2017. Measuring short-crop reference evapotranspiration in a humid region using electronic atmometers. Agricultural Water Management. 195(1):180-186.