FERTILIZER FOR PERENNIAL GRASSES IN THE CENTRAL CISCAUCASIA
The responsiveness of alfalfa and clover to the long-term use of different fertilizer systems in the field crop rotation was studied in four natural zones of the Central Ciscaucasia. A high responsiveness of crops to increasing doses of NPK has been established both with a separate application and in combination with manure (20-30 t/ha). The doses of phosphorus and potassium should prevail over the dose of nitrogen in the composition of NPK. The maximum yield of green mass of clover (31.8 t/ha) and alfalfa hay (5.47 t/ha) on leached chernozem was obtained by a triple dose of NPK. The option with organic and mineral fertilizer was slightly superior to the equivalent double dose of NPK. The largest amount of protein (20-21%) in the crop was accumulated by double and triple doses of NPK and it significantly exceeded the control without fertilizers.