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The purpose. To study features of emission of nitrous oxide from leached chernozem under the influence of increasing doses of fertilizers and receipt of fresh organic substance of various parentage; to determine necessary amount of carbon for optimization of biological processes at use of solid mineral fertilizers. Methods. Field experiments, gas-stratographic analysis, agrochemical, computational. Results. Specific losses (g N-N2O/kg C-CO2) of nitrogen from soil are diminished at manuring (dung, straw, mass of Lupine green manure crop and their combinations). The greatest specific losses of N-N2O in experiments were registered in alternatives with fertilizers. At the same time application of solid mineral fertilizers in low (100 kg/hectare a.a. in the link of crop rotation) and average (200 kg/hectare a.a.) doses on the background of straw (5 t/hectare) and Lupine green manure crop (13 t/hectare) secured decrease of indexes (even below control). That testified to fixation of part of mineral nitrogen compounds not used by plants. Thus for optimization of C/N ratio it is not required additional application of mineral nitrogen. Combination of the highest dose of fertilizers in experiment (300 kg/hectare in the link of crop rotation) with straw and green manure crop does not allow to lower specific losses of nitrogen to the level of control. That testifies to redundancy of mineral nitrogen in soil in that case. The formula of calculation of necessary amount of carbon for optimization of C/N ratio is offered at use of different doses of nitrogen fertilizers in crop production technologies. It ensures balance of mineralizing and synthetic processes in soil. Conclusions. Application of calculated doses of fresh organic substance (dung, straw, Lupine green manure crop and their combination, including mineral fertilizers) secures optimization of microbiologic processes in agro-ecosystems at cultivation crops on leached chernozem. In such conditions the nitrogen of mineral joints not used by plants metabolically linked (immobilized) by microorganisms. Emission of N2O, and doses of fertilizers, which do not exceed 200 kg/hectare a.a. in crop rotation, decreased, and became environmentally sound. |
