Productivity of potato of sprint variety, depending on the nutrition background on gray forest steppe soil of Middle Volga
The authors revealed the role of fertilizers, under the influence of which, there was a significant increase in the crops productivity. Fertilizers, applied in the calculation of the planned harvest of 25-40 t/ha of tubers, significantly increased photosynthetic activity of potato plants. Leaf area increased to 3.6-15.4 thousand square meter per hectare, the amount of leaf photosynthetic capacity during the growing season at 314-1252 thousand square meter × day per hectare, Leaves productivity to 1 thousand units of photosynthetic capacity to 13.6-29.6 kg of tubers, the coefficient of photosynthetically active radiation to 0.55-1.28%. According to the effective fertility, the productivity of tubers without the fertilizers use was 15.53 t/ha. Fertilizer application, based on the upcoming harvest tubers of 25 and 30 t/ha, provided for producing such crops. The productivity of 35.0 t/ha, on average for almost three years, has been obtained, the harvest shortfall was only 0.21 t/ha or 0.60%. On the background, calculated on productivity of 40.0 t/ha of tubers, it was lower to 3.02 t/ha or 7.55%. Maximum starch content (19.4%) was obtained on the background of which is intended to yield of 30 t/ha. The nitrate content in all versions of the experiment were below the maximum allowable concentration, although there was an rise in their number in the tubers with increasing standards of fertilizers. Marketability of the crop with increasing nutrition background was increased to 1.6-8.0%.