Soybean planting date and seeding rate effect on grain yield and profitability

Abstract

AbstractTimely soybean [Glycine max (L.) Merr.] planting is ideal for maximizing grain yield. However, weather conditions often limit farmers’ ability to plant timely. The objectives of this study were to (a) measure the effect of soybean planting date and seeding rate on grain yield, (b) identify the agronomic optimum seeding rate (AOSR; the seeding rate where soybean yield is maximized), and (c) compare the net economic return of the base treatment (May 10 to 31 planting date and 370,000 seeds ha−1 seeding rate) to the other treatment combinations. The experiment was conducted in 2020 and 2021 in Ohio at the Western (WARS) and Northwest (NWARS) Agricultural Research Stations with a split‐plot randomized complete block design with four replications. The whole plot factor was four planting dates ranging from April 25 through July 1, and the sub‐plot factor was five seeding rates ranging from 123,500 to 618,000 seeds ha−1. When water was not limiting, soybean planted in April and May yielded 8% to 26% more than soybean planted late June. In general, planting in May resulted in a lower AOSR (247,000 to 303,000 seeds ha−1), compared to planting in June, where AOSR ranged from 430,000 to 618,000 seeds ha−1. Comparative net economic return was the lowest (from $237 ha−1 to $938 ha−1) when soybean was planted after mid‐June at 123,500 seeds ha−1. These findings can help farmers improve soybean grain yield by adjusting their seeding rate based on planting date to maximize profitability.