Planting date and seeding rate effects on soft red winter wheat

Abstract

In Ohio, it is recommended to plant soft red winter wheat [Triticum aestivum (L.)] within 10 days following the county's Hessian fly (Mayetiola destructor)-free date to achieve maximum yields. However, due to wet weather in the fall and late-maturing soybean [Glycine max (L.) Merr.] varieties, wheat is often planted after the optimum time. To mitigate yield losses due to late planting, a higher seeding rate may be necessary. Objectives of this research were to (a) assess the main and interaction effects of planting date and seeding rate on soft red winter wheat grain yield, and (b) determine the agronomic and economic optimum seeding rates (AOSR and EOSR, respectively) of wheat based on the planting date. An experiment was established during two growing seasons at two locations in Ohio with five wheat planting date and five seeding rate treatments ranging from 1.24 to 6.18 million seeds ha⁻¹. Average AOSR for early and timely planted wheat was 2.69 million seeds ha⁻¹. For wheat planted approximately 4 weeks of the fly-free date and beyond that time frame, average AOSRs were 3.12 and 4.39 million seeds ha⁻¹, respectively. The EOSRs for the same three-time frames were 2.10, 3.00, and 4.37 million seeds ha⁻¹, respectively. Results also indicated a lower yield penalty for late-planted wheat in Ohio than previously observed, which may be due to mild winters and the favorable conditions for kernel development and grain fill during late spring and early summer.