The Principal Investigator is highly involved with Extension and outreach to farmers and agronomists. The results of this project will be presented in local and regional publications, meetings for farmers and agronomists, as well as the technical literature.

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A soybean crop can use about 16 inches of water during a growing season. Yield loss due to drought stress is an annual concern in western North Dakota, especially in years of below-normal precipitation.

Farmers in western North Dakota are already using advanced methods of soil and water conservation, such as no-till, but is there anything else that can be done to stretch limited water supplies? The first objective of this research was to evaluate seed-applied growth regulators that slow water use. Perhaps saving water early might reduce water stress during grain fill.

Farmers are also expressing increased interest in cover crops. Cover crops are used to protect the soil, and increase soil health. However, cover crops also take up water, a precious commodity in a semi-arid climate. The second objective of this study was to measure the water used by a rye cover crop, and if that led to reduced soybean yield.

A greenhouse and two field studies evaluated seed-applied growth regulators that slow water use by soybeans. In the field study, 4 ppm of uniconazole improved plant water status at one of the sites in early August. The treatment did not increase yield, however.

The effect of the rye cover crop on water depletion is shown. The two seeding rates were 25 and 50 lb/A, and the rye was terminated about 2 weeks before planting, and around seeding time. Time of termination was more important than seeding rate, and up to 1.5 inches of water was used by the rye. However, rainfall was timely, and yields were not decreased by the rye cover crop.

In the two years of this study, final yields of 12 to 35 bu/A were obtained. Can we explain these differences in yield, based on water stress? The lowest yield, 12 bu/A was observed at Cole Harbor. The crop, essentially, "burned up," and ended the year in severe water stress without relief. The second-lowest yield, 16 bu/A, was observed at Minot. At this site, the crop did not enter severe water stress, but was in a state of water stress for the entire grain-fill period. At the other three locations, the plants were not under water stress in early August and did not enter severe water stress. At these three sites, yields were acceptable for western North Dakota (29-35 bu/A).