Investigating maize subirrigation strategies for three northwest Ohio soils

Abstract

Drought during maize (Zea mays L.) growing season in the US Midwest can be mitigated using drainage and runoff water recycling through subirrigation. Limited information regarding subirrigation timing and intensity hinder its promotion across the region. Seven water table management strategies were simulated using DRAINMOD calibrated for three locations with different soil series in northwest Ohio, under 1984 to 2013 climate conditions, and were compared based on annual relative yield, subirrigation water volume, relative water discharge, and management intensity. Annual relative yields ranged between 63.1% and 64.4% at the Defiance site and were not significantly different between the water table management strategies. Under subirrigation, relative yields ranged from 87.3% to 93.2% and 80.4% to 90.8%, respectively, at the Fulton and Van Wert sites and were significantly larger than under free subsurface drainage. Annual subirrigation water volumes were significantly lower under continuous subirrigation from V3 stage at all three locations. Subirrigation water volumes at the Fulton and Van Wert sites were particularly lower with continuous subirrigation starting at V9. Relative water discharges were similar across all water table management strategies at the Defiance site and larger under free subsurface drainage at the Fulton and Van Wert sites. Free subsurface drainage was the most appropriate option for the Defiance site in terms of water table management because subirrigation did not improve the relative yield but consumed water (and, consequently, energy for pumping). For the Fulton and Van Wert sites, continuously subirrigating from V9, with the control weir set at 61 cm below ground surface and raised to 35 cm below ground surface at tasseling improved the relative yield while using less subirrigation water volumes and generating no greater relative water discharge (hence no greater dissolved nutrient loads) than the other subirrigation options. This strategy potentially reduces labor costs at locations where subirrigation is appropriate, enhancing the economic viability of subirrigation, and is the most applicable strategy to other major maize-growing areas in the Midwest. Results indicate water table management and subirrigation will benefit Midwestern maize production under projected climates, which suggests increased potential for water stress in most growing seasons by 2041 to 2070. Future studies, extending this approach to more diverse regions, accompanied by more in-depth economic assessments, are needed to further evaluate potential benefits of subirrigation.