MATHEMATICAL MODELS FOR HUMUS BALANCE FORECASTING
In modern agriculture the improvement of crops productivity is highly dependent on anthropogenic chemical factors. Due to this fact, the present-day agrophytocenoses are characterised by low species richness, strict consistency of agrotechnological operations and the main phenological cycles of the dominating crops, that results in the decreased resistance of agrobiocenoses to biotic and abiotic stresses, and consequently - the decline of soil fertility. Sustained positive balance of humus is necessary for providing sustainable high yields and the conservation of physical and chemical properties and biotic activity of soil. Modern agrochemistry and agronomy involve the application of various methods for crop nutrients calculation, aimed at soil fertility conservation. However, the conducted analysis has shown a number of disadvantages of these methods: forecrops and degree of soil development are not taken into account, calculation of nutrients dosages is carried out by averaged agrochemical properties of soils of agricultural enterprises, that has a considerable effect on the coefficient of uptake of nutrients contained in soil and fertilizers by plants and a number of other indicators. In this connection, this data should be considered as approximate, especially being taken from reference sources. For this reason, the research workers of the Institute of engineering support agriculture - branch of FSAC VIM have developed mathematical models of calculation of nutrients dosages for the major crops of Central Russia on the basis of multiannual experimental data of the Federal Research Center «Nemchinovka» and data obtained from field experiments conducted by the Geographic Network of the All-Russian Scientific Research Institute of Agrochemistry. The developed method for calculating nutrients dosages is based on crop yield forecasting. The developed method for calculating nutrients dosages is based on crop yield forecasting. The novelty of the developed mathematical models lies in consideration of all the known sources of macronutrients supply in soil solution, put in the basis of aggregate variables (algebraic sum of variables) for determining parameters of nitrogen, phosphorous and potassium nutrition for crops.