Efficiency of fertilizers of winter wheat after soybean and combined soybean and com fields on leached chernozem

The results of research in stationary field experiment on studying of fertilizer impact on productivity of winter wheat after soybean field for seed and combined fields of com and soybean for green mass. It was ascertain from the second rotation data (1978-1982), that optimum norm of main fertilizer of winter wheat after both preceded crops is N 90P 60 providing increases of seed yield 54,1 and 38,6 % and recoupment of a kilo of acting substance fertilizer 12,9 and 10,0 kg of seed of additional yield. Increasing of optimum norm of fertilizer in 1,5-2 times and including of potassium in fertilizer composition is ineffective. The portion of impact of agrochemical factors on yield of winter wheat depends on its quantative indexes as well as in preceded crops. The labile phosphorus content in soil (48,1 %) exerted the greatest influence on yield of winter wheat after soybean and concerning cornsoybean mixture it was nitrate nitrogen (24,1 %). Fertilized winter wheat with yield up took in 1,5-1,9 more nourishment elements than unfertilized. Expenditure of nitrogen, phosphorus and potassium for forming of ton of seed was more in 8,9-22,7 % after maize-soybean mixture than after soybean.