Sugar Beet NPK Utilization Ratios from Fertilizers and Soil in Fallowand Clover Links of a Crop Rotation in the Central Black-Earth Region
More full use of P<sub>2</sub>O<sub>5</sub> and K<sub>2</sub>O mineral fertilizers by sugar beet was noted in fallow link of a grain–beet crop rotation, and the same was marked for N in clover link. In the link with clover, more intensive use of soil and fertilizers NPK by sugar beet was noted when using the systems of N45P45K45 + manure 50 t/ha in fallow and N120P120K120 + manure 50 t/ha in fallow. In the link with fallow, the systems of N120P120K120 + manure 50 t/ha in fallow and N135P135K135 + manure 25 t/ha in fallow had a similar effect. Under influence of fertilizers, return of nitrogen to agricultural ecological system in the fallow link was by 21.8–164% more than in the clover one. Return of P<sub>2</sub>O<sub>5</sub> and K<sub>2</sub>O under the same conditions was by 5.37–77.9 and 4.12–35.0% more, correspondingly. The doses of N135P135K135 + manure 25 t/ha and N190P190K190 and N120P120K120 + manure 50 t/ha promoted entire return of N and P<sub>2</sub>O<sub>5</sub> in both links.