Application of green clover manure in winter wheat growing
The field experiment studied the value of precursors for winter wheat (Triticum aestivum) on dark gray podzolic light loam soil, in particular the possibility of replacing some mineral fertilizers with green manures. We found that the highest grain yield (6.89 t/ha) of winter wheat of the Yulia variety was obtained in the variant with plowing down of the green mass of the first mowing of meadow clover (Trifolium pratense) in June. The yield (6.64 t/ha) of winter wheat was also high in the variant with the plowing down of the second mowing of the green clover mass in August. The yield of winter wheat decreased to 6.42 t/ha in the variant with mowing the green mass on one mowing and semi-steam tillage and 6.32 t/ha with clover application for two mowings, i.e., removal of biomass from the field. The results showed that the impact on the yield of winter wheat, the placement of wheat after clover with the plowing down of the first mowing of clover on green manure is equivalent to the application of mineral fertilizers at the rate N90P30K60; thus, clover as a precursor is an essential factor in biologization of cultivation technology. Yields decreased for winter wheat sowing after winter rape to 6.01 t/ha and after soybeans to 5.79 t/ha. These two precursors are valuable for wheat, but the yield decreased by 0.88 t/ha and 1.1 t/ha, respectively, compared to tillage at the first mowing of clover. It was the lowest for placement after unwanted precursors. Thus, sowing of wheat on wheat led to a drop of the yield to 5.24 t / ha, and after corn for grain - to 4.89 t/ha. The increase of yield from the choice of the best precursor (clover with plowing down of the first mowing) compared with the worst precursor (corn for grain) is 2.0 t/ha. Simultaneously, the increase of the rate of application of mineral fertilizers from N60P30K40 (N60) to N150P60K100 (N60 + N60 + N30) caused the increase of yield by only 1.25 t/ha.