NITROGEN FLUXES IN EROSIONAL AGROLANDSCAPE UNDER OATS GROWN IN THE THIRD CYCLE OF CROP ROTATION (<sup>15</sup>N STUDY)
The consumption of fertilizer nitrogen (labeled with <sup>15</sup>N) and of soil nitrogen by plants and its immobilization in soddy-podzolic soil on the slope of eastern exposure decreased, and the gaseous nitrogen loss increased when going from the near-watershed part of the slope to its lower part. The localization of nitrogen fertilizer increased the utilization of fertilizer nitrogen by plants and its immobilization and decreased the gaseous nitrogen loss on all elements of the slope. The highest yield of oat grain was obtained on the near-watershed part of the slope at the local application of nitrogen fertilizer. The localization of nitrogen fertilizer increased the environmental stability of oat agrophytocenosis on all elements of the slope.