BALANCE OF NITROGEN OF FERTILIZERS OF SYSTEM SOIL-PLANT UNDER GRAIN CROPS ON SOD-PODZOLIC SANDY SOIL

Abstract

On sod-podsolic sandy soil the structure of balance of nitrogen in system soil-plant depending on doses and terms of entering of nitric fertilizers is studied. It is established, that in a nitric nutrition of plants soil nitrogen prevails. Efficiency of barley and winter rye on 80-85% is formed at the expense of soil nitrogen and on 15-20% at the expense of nitrogen of fertilizers. In grain 68-72% of all nitrogen of fertilizers absorbed by plants concentrate. Operating ratios of nitrogen of fertilizers fluctuate depending on doses and terms of entering of nitric fertilizers from 30 to 38%. Fractional application of nitrogen promotes increase of factor of its use on 5-8%. At increase in doses of fertilizers the size of consumption of nitrogen plants increases, however operating ratios decrease. In a soil profile it is fixed from 21 to 40% of nitrogen of fertilizers. With increase of doses of fertilizers the absolute sizes of fastening of nitrogen increase, relative decrease. The basic quantity (65-72%) of nitrogen fixed in soil concentrates in arable (0-20 cm) layer. Fractional entering of nitric fertilizers promotes decrease in migration of nitrogen in underarable horizons. Losses of nitrogen as a result of washing away and denitrification make depending on doses and terms of its entering from 23 to 47%. High speed immobilization and nitrogen fixings promote decrease in its losses. Increase of doses of nitric fertilizers leads to increase in absolute and relative losses of nitrogen, fractional application - to their decrease on 5-6%.