Dr. Chris Henry

Associate Professor and Water Management Engineer|University of Arkansas

2024 Abstract - IRRIGATION SESSION - THE NEW CLIMATE SMART ROW RICE, 60% LESS WATER AND NITROGEN WITH SAME YIELDS: A patented pitless recirculating pump system (PRPS) was installed at the University of Arkansas Division of Agriculture Northeast Rice Research and Extension Center. The purpose of the study was to demonstrate at a large field scale how the implementation of the PRPDS can maintain furrow irrigated rice production using less water and nitrogen. A documented yield gap of 16 BPA currently exists between FIR and flooded rice production systems. The PRPS was used to fertigate (1) 32% Urea Ammonium Nitrogen (UAN) and (2) YaraLiva UCAN-23 (Nitrate-N 8%, Ammonium-N 5%, urea-N 10%, and 4% Ca). Two paired fields (side-by-side, equal slope, 45 and 50 acres, respectively) were both planted on the same date with RiceTec FP 7521 hybrid. The control field (45 acres) was conventionally furrow irrigated (every 3-5 days based on soil-moisture sensor readings) with 180 lbs-N/ac (applied in four equal aerial applications). The control field’s water and nitrogen use was compared to the experimental field (50 acres), incorporating the PRPS (where irrigation water was recirculated continuously during the growing season). The PRPS-equipped experimental field utilized liquid fertilizers applied via fertigation weekly, starting at 5-6 leaf until boot. The PRPS experimental field yielded 6.2 bu/ac more than the control field, although the yield difference was insignificant (p=0.12). Normalized Differential Vegetation Index aerial maps and GreenSeeker measurements were used to determine subsequent weekly liquid fertilizer volume. A total of 77 lbs-N/ac was applied via fertigation over five weeks versus 180 lbs-N/ac for the control field. Water use was greatly reduced, with the pitless tailwater system applying 9.7 ac-in/ac and the control 25.6 ac-in/ac. Methane, carbon dioxide, and nitrous oxide emissions were measured during the study using Eddy covariance (near real-time measurements) devices and standard manual chamber collection methods. The PRPS for water management and weekly fertigation of nitrogen shows promise in reducing overall water and nitrogen use and provides a unique opportunity to address mid-season nutrient deficiencies that are often difficult to correct. . ------ 2024 Abstract - ROUNDTABLE SESSION - USING SOIL MOISTURE SENSORS ACROSS THE ENTIRING FARMING ENTERPRISE: LESSONS LEARNED FROM THOSE WHO ARE DOING IT: Utilizing Soil Moisture Sensors across the entire farming enterprise is challenging and is potentially a capital-intensive process. Lessons learned from utilizing soil moisture monitoring, the successes, and pitfalls, will be shared in this farmer panel session.