Assimilation surface and photosynthetic activity evaluation of winter wheat planting according to forecrops and mineral fertilizers

The article shows the results of multi-year researches on the photosynthetic activity of winter wheat plantings according to forecrops and mineral fertilizers. The studies were performed in a two-factor experiment. Forecrops of winter wheat affected to the formation of the assimilation mechanism of plants. This influence can be seen in all phases of wheat growth. It was revealed that the best indicators were ensured by the planting of grain crops with seeding on green manure. For these variants, the leaf-area duration in the flowering phase was 42.6-49.7 thousand m2 / ha. The cultivation of bean cultures to grain was slightly lower in this indicator. The leaf area was 3.6-20.0% smaller depending on the cropping. The use of bean cultures as green manure crops led to an increase in the photosynthetic potential to 2449.1-2671.8 thousand m2/day / ha, which is 6.1-12.6% more than in the variants where bean cultures were grown to grain. The greatest photosynthetic potential was with the use of lupine to green manure. Application of mineral fertilizers also had a positive effect on the development of the assimilation mechanism. On complete fallow without mineral fertilizers, this indicator was 2325.7 thousand m2×day / ha, and when additional fertilizers were applied at a dose of N54P52K52, the photosynthetic capacity increased by 70.5 thousand m2×day/ha or by 30%. Following the green manure crops, the yield of winter wheat slightly outperformed the crop in the variants where bean cultures were grown to grain, both without fertilization and on the background of fertilizers. The application of mineral fertilizers promoted a greater increase in the yield, in contrast to the forecrop. With the use of mineral fertilizers, the yield increased by 11-12% in similar variants.