N.N. Shapovalova, E.P. Shustikova
Stavropol Research Institute of Аgriculture, Nikonova str., 49, Mikhailovsk, Stavropol krai, 356241, Russia
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Summary. In 1976 on the experimental field of Stavropol Krai under the leadership of L.N. Petrova the stationary experiment was laid to study the effect of different doses and combinations of fertilizers on the efficiency of field rotation and indicators of soil fertility. The experimental plan included annual application of the following doses of fertilizers: N0, N30, N60, N90, N120, N150, P120K120, P120K120N30, P120K120N60, P120K120N90, P120K120N120, P120K120N150, P0, P30, P60, P90, P120, P150, N120K120, N120K120P30, N120K120P60, N120K120P90, N120K120P120, N120K120P150. It was 24 variants in total. Within 5 rotations it was conducted 21-fold stacking of nitrogen and phosphate fertilizers and 15-fold one of potassium fertilizers. Since 2006 it was started studying of aftereffects. Long-term application of fertilizing agents created various conditions for plant nutrition. In general, the yield increase of crops raised in the series: soybean, winter wheat after fallow, spring barley, flax, winter barley, winter wheat after flax. The average annual growth of productivity over 6 years of aftereffect was 0.67-1.22 t/ha of grain units, or 18-32%, relative to the variant without fertilizers. The analysis of the statistical characteristics shows that the increase in productivity of field crop rotation is due to the level of nitrifying capacity of the soil, determined by Kravkov, and the amount of mobile phosphates. On the basis of the variation of these factors it was calculated the complex index – the index of cultivated soils, which was accepted as a basis for characterization of the level of fertility of a plot. Its optimum value is within 1.1-1.5 units when P2O5 content is not more than 60-65 mg/kg and the ratio between nitrifying capacity and the content of available phosphorus 1:1.5.
Keywords: crop yield, agrochemical parameters, nitrifying ability, mobile phosphorus, index of cultivation, ordinary black soil.
Author Details: N.N. Shapovalova, Head of Laboratory; E.P. Shustikova, Cand. Sc. (Agr.), Senior Researcher.
For citation: Shapovalova N.N., Shustikova E.P. Change in crop yield depending on the content of n, p and k in ordinary black soil // Dostizheniya nauki i tekhniki APK. 2015. V.29. No 8. pp. 32-35 (In Russ)