The purpose of the experiment was to study the influence of periodic using of neutralized phosphogypsum on the fertility of meadow chernozem soils of Krasnodar Territory, achieving of the appropriate level of rice agrocenosis productivity, and the quality of rice grain. The timing of the effective use of phosphogypsum as a phosphorus fertilizer was revealed during the experiment. It was proved that the same level of mobile phosphorus content in rice soils can be achieved by using either phosphogypsum or standard phosphorus-containing fertilizers. Given the fact that nitrogen and potassium fertilizers are already used, using of phosphogypsum provides an opportunity of getting a 6,34 tons/hectare yield of rice (the same result was achieved using N120P80K60 fertilizer). 3 years after re-fertilizing the soil with phosphogypsum we can notice that effectiveness of phosphogypsum in optimization of rice mineral nutrition program contributes to cost savings of 4155 RUB/hectare in comparison with traditional fertilizing system.

The article presents the results of modeling the cultivation of barley of the Eifel variety on leached chernozems of the Bashmakovsky district of the Penza region. In order to carry out modeling, the framework Local information and reference system for the optimization of land use was deeply adapted. The adaptation of the software modules to the climatic and soil conditions of a particular study area allowed one to reach 7% errors in modeling the cultivation of agricultural crops in the presence of a set of indicators necessary for constructing a model. Technological calculations of the model made it possible to reduce the number of minimum required technological operations, as well as to rationally distribute the application of mineral fertilizers for the planned yield. The economic calculations of the model made it possible to achieve a high production profitability of 66 ± 7%. The constructed model was tested on the experimental field of «Bashmakovskiy khleb» JSC in 2020. Practical verification has shown the possibility of using the model in agricultural production under normal climatic conditions and its high correlation with the actual results obtained [1]. Statistical analysis of the calculated data of the model and the actual yield with the achieved economic indicators in the conditions of the model field showed a level of reliability of calculations of 95%.