Fertilizer Management Strategies of Soybean (Glycine Max, L. Merrill) in Northcentral and Northwestern North Dakota
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Abstract
Soybean (Glycine max L. Merrill) is a new cash crop for north central and northwestern North Dakota producers. Soils and climate in these new soybean areas differ from those regions where the current fertilizer recommendations were based. Northcentral and northwestern North Dakota is more undulating, drier, cooler, and has differencing soils than eastern North Dakota and Minnesota. A three-year study to evaluate soybean best management practices was conducted during the 2016 to 2018 growing seasons. Each year, the study consisted of two sites and 12 treatments. By design, one site was on acidic (pH < 6) soil while the other was on alkaline (pH > 7.3) soil. Both site treatments were: untreated check, inoculated with rhizobia (B. japonicum L.), broadcast urea (55 kg ha-1), broadcast MAP (monoammonium phosphate, 11-52-0) (110 kg ha-1), in-furrow 10-34-0 (28 L ha-1), in-furrow 6-24-6 (28 L ha-1), foliar 3-18-18 (28 L ha-1) at V5 and R2 growth stages, and foliar 3-18-18 (28 L ha-1) with sulfate (1.1 kg ha-1) at V5 and R2. The acidic sites alone included two treatments of sugar beet (Beta vulgaris L.) waste lime (4.4 Mg ha-1 and 8.8 Mg ha-1). The alkaline sites alone received treatments of iron ortho-ortho-EDDHA (1.8% Fe) (7.1 L ha-1), and sodium (naked- without Fe) ortho-ortho-EDDHA (7.1 L ha-1). Treatments did not impact soybean yield, protein content or oil content at the 95% significance level. Sugar beet waste lime surface applied at planting at rates of 4.4 Mg ha-1 and 8.8 Mg ha-1 increased soil pH to a depth of 10 cm over the course of the growing season.