Quantification of Soybean Leaf Senescence and Maturation as Impacted by Soil- and Foliar-Applied Nitrogen

摘要

Ohio producers often question whether fertilizing soybeans [Glycine max (L.) Merr.] with nitrogen (N) will increase yield. Foliar- and soil-applied N have been evaluated throughout the Midwestern US, but few studies have compared the response of commercially available foliar N applications to soil-applied N within the same environments. Additionally, there is limited information on the impacts of N application on soybean maturation and leaf senescence. The objectives of this study were to: (i) evaluate the effect of various rates of soil-and foliar-applied N at different growth stages on the maturation of soybeans; and (ii) quantify the effect on soybean yield and quality (protein and oil) of soil and foliar N application. A field study was conducted in 2017 at two Ohio locations using a randomized complete block design with full factorial of soybean cultivar (one Maturity Group II and one Maturity Group III) and N application treatment (unfertilized control and four N applications varying in source, rate, and timing). The maturity date, yield, and quality varied among cultivars. Leaf senescence was impacted by weather conditions to a greater extent than N application. Maturity date was impacted by N application, but all treatments matured within1 day of one another and were similar to the untreated control. The N treatments had minimal effects on leaf senescence, yield, seed protein, and seed oil. Future studies should focus on expanding these results in additional environments and with more Napplication treatments.