In irrigated agriculture, the amount and the timing of irrigation play a crucial role in obtaining a sustainable higher yield with minimum adverse effects on the environment. Insufficient irrigation on critical growth stages results in lesser crop yield than the genetic potentiality of a given variety; and excess irrigation leads to higher pumping cost, quick depletion of water resources, leaching of nutrients, and environmental pollution. Soybean is the second largest irrigated crop in ND, however, there is a lack of information on the optimum amount and timing of irrigation of this crop for western ND. In this project, 12 irrigation treatments (based on amount x timing i.e., growth stage) will be applied using an automated linear system capable of variable rate application under field conditions. The amount of water to be applied, as per treatments, will be determined based on available soil moisture, precipitation forecasts, current rainfall, soil infiltration rate, and crop growth stages. The research results will be communicated to clientele through presentations at field days, workshops, and publications. The outcomes of this study will help soybean producers of ND to determine irrigation schedules that enhance yield, water productivity, and soil health; thus, an increased sustainable high farm profit.

I) The main objective of this project is to determine the optimum amount and timing of irrigation for enhanced soybean yield, quality, and water productivity.
II) The secondary objectives are to assess the effect of irrigation treatments
a. on soil health manifested by changes in soil physical and chemical properties.
b. on the manifestation of soybean diseases including but not limited to white mold.

• A technical report on the outcomes of the project.
• An executive summary of the project.

According to USDA FSA Crop Acreage Data of 2020, there were about 276,982 acres of irrigated cropland in North Dakota, and soybean was the second largest irrigated crop (63,686 acres) preceded by corn (87,124 acres) and followed by beans (27,366 acres) (USDA-FSA, 2020). According to USDA's 2013 Farm and Ranch Irrigation Survey (USDA-ERS, 2020), about 82 percent of irrigated farms in North Dakota are using “condition of a crop by observation” followed by 56 percent using the “feel of the soil” as means of deciding when to apply water. One of the reasons for these practices is the lack of information on appropriate timing and amount of irrigation for a given crop, including soybean. Information on the appropriate amount and timing of irrigation from this research will help western ND soy producers to apply the judicial amount of irrigation at the proper time. The ultimate benefits will be enhanced yield, quality, water productivity, and soil health, and decreased leaching, environmental pollution, disease incidence; thus, a higher farm profit.