Core Ideas Irrigation water management practices decreased total water applied by 39.5%. Irrigation water management practices increased corn grain yield by 6.5 bu/acre. Irrigation water management ...

There is limited adoption of irrigation scheduling tools that could improve application timing and water use efficiency in row‐crop production systems common to the mid‐southern United States. The objectives of this manuscript are to describe a sensor‐based irrigation scheduling method and review its effects on water applied and crop productivity. The effects of scheduling irrigation based on the recommended construction, deployment, and utilization of the WATERMARK 200SS granular matrix (WATERMARK) sensor on water applied, crop productivity, and crop water use efficiency were reviewed for corn (Zea mays L.), soybean [Glycine max L. (Merr.)], peanut (Arachis hypogaea L.), and cotton (Gossypium hirsutum L.) produced in the Prairie region of Arkansas and the Delta regions of Arkansas and Mississippi. For corn and soybean, on‐farm research indicates the recommended irrigation threshold of −85 to −100 cbar reduces total water applied up to 40% while maintaining or improving yield up to 3%, net returns up to $39 acre⁻¹, and irrigation water use efficiency up to 51% for soil textures ranging from very fine sandy loam to clay. Similarly, for peanut and cotton, results indicate the irrigation threshold that minimizes water use while maximizing yield and net returns is −50 cbar and −100 cbar, respectively. The recommended method for scheduling irrigations with a WATERMARK 200SS soil moisture sensor promotes the efficient use of water in row‐crop production systems common to the mid‐southern USA.

Agricultural withdrawal from the Mississippi River Valley Alluvial aquifer (MRVAA) exceeds its recharge rate, causing groundwater declines and cones of depression across the midsouthern United States. This research was conducted to determine whether sensor‐based irrigation scheduling of soybean [Glycine max (L.) Merr.] could improve yield and profitability while minimizing consumptive water use. The effects of season‐long soil water potential (SWP) threshold (−50 and −85 centibar [cbar]) on consumptive water use and on agronomic and economic parameters were compared with scheduling irrigations as a function of growth stage (VN–R2, R3–R4, and R5–R6.5) and SWP threshold (−50, −85, and −125 cbar) on a Dundee silty clay loam (fine‐silty, mixed, active, thermic Typic Endoaqualfs) near Stoneville, MS, from 2015 through 2017. Decreasing the season‐long SWP threshold for soybean from −50 to −85 cbar reduced consumptive water use 49% while having no adverse effect on yield, returns above irrigation costs, or irrigation water use efficiency (IWUE). Adjusting the irrigation threshold as a function of growth stage did not improve yield or returns above irrigation costs. Our data indicate that maintaining a season‐long irrigation threshold of −85 cbars optimizes yield, returns above irrigation costs, and IWUE efficiency while reducing withdrawal for soybean irrigation from the MRVAA up to 49% relative to the −50 cbar producer standard.

Approximately 80% of mid‐southern U.S. irrigation requirements are supplied through gravity flow delivery systems with inherently low application efficiency. This research was conducted to determine whether the efficiency of furrow‐irrigation systems could be manipulated through conservation tillage systems. Three experiments were conducted near Stoneville, MS, on a Dubbs silt loam to determine the effects of reducing tillage and increasing ground cover residues on irrigation application efficiency and irrigation water use efficiency. In Exp. 1, transitioning from conventional tillage to a conservation tillage system had no adverse effect on irrigation application efficiency and irrigation water use efficiency when subsoiling was included. For Exp. 2, replacing subsoiling with a cereal rye (Secale cereale L.) or tillage radish (Raphanus sativus L.) cover crop in a conservation tillage system either had no effect or reduced irrigation application efficiency and irrigation water use efficiency up to 10%. In Exp. 3, independent of cover crop, reducing tillage to only furrow creation had no adverse effect on irrigation application efficiency or irrigation water use efficiency relative to a conservation tillage system with subsoiling. Conservation tillage systems that include subsoiling maximize irrigation application efficiency and irrigation water use efficiency while minimizing adverse effects on yield and net returns relative to conservation tillage systems that further reduce tillage and/or increase ground coverage with cover crops. Our data indicate that soybean [Glycine max (L.) Merr.] producers in the mid‐southern United States maximize furrow‐irrigation functionality, yield, and profitability while minimizing risk by transitioning from a conventional tillage system to a conservation tillage system with subsoiling.

Water level declines in the Mississippi River Valley Alluvial Aquifer (MRVAA) are attributed largely to withdrawals for rice (Oryza sativa L.) irrigation. This study was performed to determine if alternative irrigation strategies for rice could reduce withdrawal from the MRVAA without having an adverse effect on yield and profitability. Research was conducted at 19 on‐farm locations across the Delta region of Mississippi from 2014 through 2016 to determine the effects of irrigation water management practice, i.e., conventional flood via cascade (CONV), multiple side inlet (MSI), and MSI coupled with alternate wetting and drying (AWD), on aquifer withdrawal, rough rice grain yield, irrigation water use efficiency (IWUE), and net returns above irrigation costs. Compared to CONV and MSI, up to 39% less water was applied to AWD (P ˂ .0001). Rice grain yield for AWD was not different from either CONV or MSI (P = .1343), despite substantial reductions in water use. Relative to standard irrigation strategies, AWD maintained or increased net returns up to $238 ha⁻¹ for pumping depths from 5.5 m to 122 m and diesel prices from $0.42 L⁻¹ to $0.98 L⁻¹ (P ≤ .0003). Irrigation water use efficiency was up to 59% greater for AWD relative to conventional systems due to the positive effects of the former on water use while maintaining yield (P = .0034). These data demonstrate that AWD can reduce withdrawal from the MRVAA while maintaining or improving yield and net returns relative to irrigation strategies currently employed across the midsouthern USA rice belt.

Core Ideas Irrigation scheduling in furrow-irrigated peanut will improve by developing scientific thresholds. Use of soil moisture sensors will increase irrigation water use efficiency. Proper irrig...