Soybean Water Stress Development and Mitigation in West-Central North Dakota

In recent years, soybean [Glycine max. (L.) Merr.] production has moved into west-central North Dakota, an area known for common deficits between potential plant water use and annual rainfall. Soybean seed yield reductions due to water stress are the greatest during reproductive stages of growth. In a year of limited rainfall, foliar-applications of five different water use modulating chemicals applied at early reproductive growth stages commonly reduced seed yields, while improvements were few and inconsistent. Seed-applied plant growth regulators (PGRs) were recognized as possible seed treatments to conserve soil water by reducing vegetative plant growth, thus improving water dynamics later in the growing season. In the following field study, late-terminated, fall-seeded cover crops were shown to significantly reduce spring soil water levels. However, favorable rainfall throughout the growing season buffered any cover crop or seed-applied PGR treatment effects on growing season soil water, plant water status, and soybean seed yield