Changes in the chemical composition of spring wheat strawwhen using the Rostok humic preparation in the forest-steppe of the Trans-Urals

The aim of research is to study the effect of the humic preparation Rostok on the chemical composition of spring wheat straw in the forest-steppe of the Trans-Urals. The studies were carried out in the field in the northern forest-steppe of the Trans-Urals from 2013 to 2016 on arable leached chernozem. The experiment included the treatment of crushed straw with the Rostok humic preparation, followed by its distribution on the soil surface and at a depth of 10, 20, 30 cm, simulating the distribution of plant residues in the arable layer. The exposure period was 12 months. It was established that the treatment of straw with the humic preparation Rostok reduces unproductive losses of nitrogen and promotes the release of phosphorus and potassium from the straw. For 12 months of exposure the nitrogen content in the straw treated with water and located on the soil surface (control) decreased by 2.8 times relative to the initial values and reached 0.25 ± 0.05 %. The nitrogen content in the straw treated with the Rostok humic preparation reached 0.41 ± 0.14 %, which is 1.6 times more than the control. By the end of the exposure period, the C:N value in the straw treated with a humic preparation and located on the soil surface was 108 ± 11 units, which is 1.6 times less than the control. Values of nitrogen content in plowed plant residues after 12 months of exposure of the two variants overlapped each other (control 0.66 ± 0.08 %, Rostock 0.73 ± 0.12 %). This trend was also observed in the ratio of carbon to nitrogen (control 72 ± 16 %, Rostock 60 ± 4 %). The nitrogen content in the straw depends on 31 % of localization and 20 % on the humic preparation Rostok. The nature of the change in phosphorus and potassium in the straw of grain crops by more than 80 % depends on the treatment of straw with the humic preparation Rostok, while the localization of the straw does not have a significant effect.