Initiation of Furrow Irrigation in Corn on a Dundee/Forestdale Silty Clay Loam Soil with and without Deep Tillage
2017
Pringle, Horace C III | Falconer, Larry | Krutz, Larry J. | Fisher, Daniel K.
Improving corn ( L.) furrow irrigation efficiency with proper irrigation scheduling will help conserve dwindling ground water resources in the Mississippi Delta. The objective of this study was to develop irrigation initiation recommendations for corn grown on a deep silty clay loam (SiCL) soils with and without deep tillage. Studies were conducted during the 2009, 2010, 2011, and 2012 growing seasons on a Dundee (fine-silty, mixed, active, thermic Typic Endoaqualfs) /Forestdale (fine, smetitic, thermic Typic Endoaqualfs) silty clay loam in the Mississippi Delta. Furrow irrigation was initiated at multiple timings with corn yield and net returns being later determined. Soil water potential (SWP), soil water deficit (SWD), and growth stage were compared at these initiation timings to determine which parameter or combination of parameters consistently predicted the greatest yields and net returns. Deep tillage increased irrigated yield three out of four years with no interaction between the main effects of tillage and irrigation initiation indicating there was no justification for different irrigation scheduling recommendations with (DT) or without deep tillage (NDT). Irrigation that provided adequate moisture from tasseling to physiological maturity maximized yields and net returns all four years of the study. Results indicated furrow irrigations on this soil should be initiated at the V15-V16 growth stage (3-5 days before VT) or later, when SWP readings are -50 kPa or drier or when SWD estimates are 100 mm or lower and rainfall is not imminent. These results reinforce the sensitivity of corn to drought stress during tasseling, silking, and pollination, and the need to ensure that water is not limiting as the corn enters into this critical time period.
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