THE EFFECT OF INCREASED DOSES OF FERTILIZERS ON HARVEST OF GRAIN CROPS

The results of studies of the effect of increased doses of organic and mineral fertilizers on the yield of winter wheat and barley are presented. The soil of the experimental site is sod-podzolic and medium-podzolic sandy loam. The predecessor is a lupine-oatmeal mixture for green food. For winter wheat, manure, lime and phosphorus-potassium fertilizers were applied for the main plowing, nitrogen fertilizers in the spring for top dressing, in the tube phase, from autumn to pre-sowing cultivation and in the earing phase. Since autumn, barley, manure, lime and phosphorus-potassium fertilizers have been applied for winter plowing. Experimental data show that the use of fertilizers does not affect the field germination of winter wheat and barley, but significantly increases the number of productive stems and the coefficient of productive bushiness of plants. For winter wheat and barley, with a decrease in the seeding rate, the number of grains increased and a higher weight of 1000 grains was obtained with sparse sowing. It has been established that the effect of seeding rates on productivity. The most effective doses of mineral fertilizers against the background of manure and lime for winter wheat and barley are NPK of 60-90 kg /ha of active substance. Their further increase does not give an increase in yield due to the strong lodging of plants during the grain filling period, which leads to a sharp drop in their productivity [1, 2]. On sandy loam soils containing 15-20 mg of P205 and K20 per 100 g of soil, the best dose of mineral fertilizers for winter wheat is N90P40K40, i.e., the dose of nitrogen is not higher than 90 kg/ha. On sod-podzolic sandy loam soils containing 8-10 mg per 100 g of soil nutrients, winter wheat can provide a grain yield of 40 c/ha when applying mineral fertilizers in doses of 90 kg of active substance per hectare on a background of 40 t/ha - manure and liming. Barley with a background of 30t/ha of manure and liming reacts positively to the application of mineral fertilizers in doses of 60-90 kg/ha of the active substance. Further increase of fertilizer dosage negatively affects the yield due to strong lodging of plants.