Crop rotation productivity depending on the system of mineral fertilizers

In the field stationary experiment on gray forest medium loamy soil, the productiveness of short-rotation five-field crop rotations has been studied with 30%, 40% and 60% of legumes in the structure against the background of application of various mineral fertilizer systems - for the planned crop (balanced method) and depending on the income of crop-root remains (CRR ) of the predecessor at the rate of 20, 30 and 40 kg of active substance NPK fertilizer for 1 t of CRR. As a result of the research it was established that on average for two rotations the highest productivity of one crop rotation field was obtained in a variant with the usage of mineral fertilizers calculated by the balance method in a crop rotation with 60% saturation with legumes, where 72.2 GJ/ha was obtained. Almost the same productivity (72.1 GJ/ha) was provided by the option with application of 20 kg as NPK per 1 ton of PKO precursor in rotation with 40% legumes. At the same time, with an increase in the share of legumes in the structure, the productivity of crop rotations increased both without the use of fertilizers and against the background of their application, although in the second case it was less obvious. The highest rise of the unfertilized background for all crop rotations was obtained with application of 40 kg for 1 ton of CCR. The rotation with 30% saturation legumes it amounted to 35%, from 40% - 25% and 60% legumes in the structure - 33%. With an increasing in the proportion of legumes over 40% against the background of fertilization, a slight decrease in the productivity of crop rotations (60% of the legumes in the structure) was noted. However, in this case, even at lower fertilizer application doses (20 kg bp NPK per 1 ton PKO precursor), a higher level of productivity was obtained than in the crop rotation with 30% saturation with legumes.