PRODUCTIVE POTENTIAL AND QUALITY OF OVERGRAZED RANGELANDS SUBJECTED TO OVERSEEDING AND FERTILIZATION

In order to increase the yield and quality of rangelands, establishment of the desirable forage species into these areas must be maximized. During 2013-2015 there was organized an experiment in order to increase the productive potential and quality by overseeding and fertilization with mineral fertilizers. In a randomized complete block in a split-plot arrangement, overseeding (unseeded and seeded with a mixture of grasses and legume species) was assigned to the main plots. Subplots were allocated to 18 fertilization composed of three nitrogen (0, 60 and 120 kg N ha(-1)) and phosphorous (0, 60 and 120 kg P ha(-1)) and two potassium (0 and 80 kg K ha(-1)) rates. In the second year of trial, the rates of desirable perennial species (20% vs. 60%) and yield of crude protein (444.4 vs. 567.7 kg ha(-1)) in overseeded rangeland were higher than that of unseeded rangeland due to the contribution of orchardgrass (Dactylis glomerata L.) and alfalfa (Medicago sativa L.) in the seed mixture used. The NPK fertilizer increased the percentage of grass and legume families of the rangeland. High-dose N fertilization with P and K had higher efficiency for seeded rangeland, whereas the efficiency of N with P were higher for unseeded in terms of yield, quality, and net benefit. In conclusion, the yield, quality, and profitability of rangelands degraded can be maximized by fertilizing with N up to 120 kg plus 60 kg P and 80 kg K ha(-1) and overseeding with Dactylis glomerata and Medicago sativa.