Nitrogen Consumption in a Second-Year Perennial Legume–Grass Mixture (15N Labeling)

Abstract

Abstract—The level of nitrogen consumption in the eroded sod-podzolic soil in a water-parting area of the slope with crop rotation cycle three was estimated, and the values were compared with the lower part of the slope. The consumption of nitrogen from nitrogen fertilizers by legume–grasses was increased by 20%, the consumption of soil nitrogen by 67%, and the consumption of symbiotic nitrogen by 23%. The immobilization of nitrogen from fertilizers is reduced; nitrogen loss in the gaseous form increases. In case of local application of nitrogen fertilizers, the level of nitrogen consumption from fertilizers was increased by 14%, soil nitrogen by 7–10%, and symbiotic nitrogen by 26–53% compared with the scattered method of application. Local application also provides a higher level of nitrogen consumption (by 1.2–1.2 times) and nitrogen immobilization (by 1.2–1.2 times) and lower amount of nitrogen lost in a gaseous form (by 1.6–2.6 times). The productivity of legume–grasses increases by 6–11%; the content of crude protein in phytomass increases by 0.3–1.1%; the content of nitrates is lower by 7–16%.