Physical fractions of gray forest soil of Vladimir's Opole and its relationship with crop productivity of agricultural crops

In the physical fractions of gray forest soil (agroseraya typical): clay (up to d = 0.001 мм), light (lighter than 2 g/cm3) and the residue fraction, the contents of total carbon and phosphorus (total, organic and mineral forms) were determined. We have found that fertilizing increased the content of total carbon in the soil after 20 years of rotation system. Content of light fractions also increased. Mineral fertilizers reduced the content of organic carbon in the light fractions of this soils, this effect requires further study. The application of lime and manure reduced the content of clay fraction, but increased the content of total carbon in it. The yield of cereals and perennial grasses depended little on the amount of total carbon in the soil and its clay and light fractions. In this case, its feedback is established with the content of light fraction and carbon in the residue. The yield of grain crops is proportional to the proportion of mineral phosphates and weakly dependent on organic forms in the subsurface horizon. In general, the yield of cereals increases with the application of mineral fertilizers. The effect of manure was less pronounced.