Balance of nutrients in arable soils of the forest-steppe of the Omsk region

The aim of the research is to reveal the regularities of changes in the balance of nutrients in arable soils of the forest-steppe of the Omsk Region in case of long-term use in agriculture. The research is based on the results of local monitoring from 1994 to 2018 on benchmark plots ,laid on agricultural land, and on the materials of a large-scale agrochemical survey (1966-2018). Objects of the research were soils. It has been established that the balance of nutrients in the Omsk Region in 1966-2018 has been mostly negative, especially in the last decades of observations. The value of the balance for the generalized periods depends on the amount of fertilizer application. The increase in the volume of their introduction from 1986 to 1990 contributed to a decrease in the negative balance of nutrients down to 11.4 kg per hectare of arable land. The deficit of nitrogen balance decreased by more than 2 times, that of potassium by 1.5 times, remaining still negative, since the supply of nitrogen and potassium was significantly inferior to their expenditure part. The parameters of the balance of nutrients should be used for long-term planning of the use of fertilizers in farms and in the region. The need for fertilizer nutrients in arable soils of the forest-steppe of the Omsk Region is presented.