Irrigation Water Management Practices that Reduce Water Requirements for Mid‐South Furrow‐Irrigated Soybean

Abstract

Withdrawal for agricultural uses has decreased water levels in the Mississippi Alluvial River Valley aquifer (MARVA), and Mississippi state regulators have responded by requiring withdrawal permits, establishing permitted withdrawal limits, and instituting required minimum levels of irrigation water use efficiency (IWUE) practices. The objective of this research was to determine the effect of integrating irrigation water management (IWM) practices-including computerized hole selection (CHS), surge flow irrigation (SURGE), and sensor-based irrigation scheduling-on irrigation water use, soybean grain yield, IWUE, and net returns above irrigation costs at the production scale. The experiment was conducted in the Prairie region of Arkansas and the Delta region of Arkansas and Mississippi from 2013 through 2015. The research consisted of 20 paired fields, with the same cultivar, soil type, planting date, and management practices. One field was randomly assigned as the control (conventional, CONV) and the other was instrumented with CHS, SURGE, and soil moisture sensors, that is, IWM. Flowmeters were installed in the inlets to both fields, and the farmers provided yield data. Soybean grain yield averaged 69.0 bu/acre and did not differ between CONV and IWM (P = 0.6703). Relative to CONV, IWM reduced water use 21% (P = 0.0198) and increased IWUE 36% (P = 0.0.0194). Net returns for soybean production above irrigation costs were not different between CONV and IWM, even when pumping depth ranged from 18 ft to 400 ft and diesel costs ranged from $1.60/gal to $3.70/gal (P ³ 0.5376). These results demonstrate that implementation of integrated IWM at the production scale reduces the demand on depleted groundwater resources without adversely affecting soybean grain yield or on-farm profitability.

Irrigation Water Management Technologies for Furrow-Irrigated Corn that Decrease Water Use and Improve Yield and On-Farm Profitability

“…Across the Mid‐Southern USA, furrow irrigators do not utilize computerized hole selection (CHS), a free computer program that improves irrigation application efficiency (Bryant et al, 2017). Traditionally, a single hole size is punctured in the poly‐tubing at every furrow for the entire length of the irrigation set.…”

“…Uneven furrow advancement reduces irrigation application efficiency, which is compounded on irregularly shaped fields. Computerized hole selection improves irrigation application efficiency by considering the shape of the field, length of poly‐tubing, and elevation changes along the field crown (Bryant et al, 2017). Hole sizes are computed for each furrow to ensure partitioned furrow delivery based on head pressure, creating a more uniform advance pattern.…”

“…Consequently, the IWUE was 51.3% greater in IWM relative to CONV ( P = 0.0062; Table 3). Others have noted that IWUE increased under IWM practices in soybean in the Mid‐Southern USA (Bryant et al, 2017; Wood et al, 2017).…”

Establishing Irrigation Thresholds for Furrow-Irrigated Peanuts

“…There are no reports of soil moisture sensor‐based scheduling of peanuts in the literature. However, there is evidence that sensor‐based scheduling for crops other than peanuts, i.e., soybean and rice, improves yield, net returns above irrigation costs, and/or IWUE up to 2.6‐fold in the mid‐southern USA (Bryant et al, 2017; Atwill et al, 2018; Wood et al, 2017).…”

Deficit Irrigation, Planting Date, and Hybrid Selection Impacts on a Mid‐South Corn Production System

“…Soil water tension was monitored by installing four Watermark 200SS soil moisture sensors (The Irrometer Co., Inc., Riverside, CA) in the second replication of the study in each treatment at depths of 6, 12, 24, and 36 inches. Furrow irrigation was applied through 15 inches by 9-mil lay-flat polyethylene tubing (Delta Plastics, Little Rock, AR) when the weighted average of the soil water tension over the 36-inch depth was at threshold (Bryant et al, 2017). As rooting depth would vary throughout the growing season, soil water tension values were averaged depending on the active rooting depth (Krutz, 2016 Washington, DC) (Kebede et al, 2014;Bryant et al, 2017) while the flow rate and application volumes were determined at the field inlet with an 8-inch McCrometer flow tube with attached McCrometer bolt-on saddle flowmeter (McCrometer Inc., Hemet, CA).…”