POTATO PRODUCTIVITY AND QUALITY DEPENDING ON AGROTECHNICAL CULTIVATION TECHNIQUES IN NOVOSIBIRSK PREOBYYE FOREST STEPPE
It was revealed in the leached heavy loam black soils of Novosibirsk Preobye forest steppe that the elements of cultivation technology influence the productivity and quality of potato varieties different in ripening groups: Lubava - early ripening, Nevsky-middle early ripening, Khozyaushka (hostess) - middle ripening. The experiments were conducted in the middle loam black soils containing readily hydrolyzed nitrogen - 8.10-11.76, mobile phosphorus - 16.8-22.4 and exchangeable potassium - 11.2-13.8 mg/100g of soil, salt extract pH - 5.84. The potato varieties examined were grown according to the technology common in the zone that is three-year rotation: bare fallow-potato-spring wheat. Mineral fertilizers doses were calculated with balance method for programmed productivity on the basis of accounted nutrients consumed by the yielding output, coefficients of their having been consumed from the soil and fertilizers. The experiments showed the effect of agrotechnical practices on the indexes of photosynthetic apparatus and potato plants productivity.Leaf surface was calculated with the formulas established by us for the varieties different in ripening groups. Correlation for the formulas established made up 0.798-0.923. The complex of soil cultivations was applied to the varieties different in ripening groups: rotary tillage to the depth of 12-14 cm before planting with subsequent high hilling on the 14-16th day after the planting and this made mean leaf surface to expand by 38% and tuber productivity to go up by 20-32% followed by good qualitative indexes of the produce. Balanced mineral nutrition encouraged gains in potato output in the unfertilized background up to 71%.Optimized fertilizer doses allowed to obtain high quality produce containing nitrites 5 times as little as MPC for potato. It is identified that the planting for all the three groups is efficient when it follows the wide row pattern: 90 x 25 and 90 x 35 cm with 31% productivity gain versus the common planting with 70 cm interrow. Statistics revealed that potato productivity depended on the genotype for 20-28%, technology elements - for 28-42% and seasonal conditions - for 22%. The technological elements (complexes of soil cultivation, balanced doses of mineral fertilizers, planting pattern) studied in the varieties of the three potato ripening groups provide 64% increased profitability with the coefficient of energetic efficiency up to 2.5.