The article deals with the analyzing  of determination of the term "organic agriculture". It is recommended to consider that organic agriculture,  is the systems of agricultural management of agroecosystems, which are based on the maximal use of biological factors of fertility-improving soils, agrotechnological measures of defence of plants, and also on implementation of complex of other measures which provide ecological, socially and economic expedient production of agricultural goods.

In basis of development of mathematical model of organic agriculture the definition of «Organic agriculture» and «Conception of biology of agriculture accepted higher is fixed for a production ecologically of clean products».

Essence of conception consists in that if on one ton of organic fertilizers more than 15 kg of operating matter of mineral fertilizers are brought in, begins or increases degumification of  soils and their agrophysical degradation. This correlation carries the name «coefficient  of agriculture biology ».

With the purpose of development of mathematical model for basis the formula of determination of norm of bringing of mineral fertilizers is taken by ball estimation of earth on the size of the programmable productivity:

,

where  - a norm of balanced NPK is for the receipt of programmatic harvest, kg/hectare;

           У - programmatic yield, c/hectare;

           Б - mark of bonitet of soil;

           Ц_Б - productive cost of mark of soil;

           Д_о - dose of organic fertilizers, t/h;

          О_о - recoupment of 1 t of organic fertilizers by the increase of harvest;

           О_м - recoupment 1 center of operating matter of mineral fertilizers  by the increase of harvest;

           А - a correction coefficient on the group of soil.

For the calculation of mass of bedding pus from the different type of animals comfortably to use middle information on the output of mixture of excrements and urine from a conditional head (living weight is 500 kg) is utilized after a formula:

,

where М_п.г.  –  output of manure, kg; 

          М_е –  mass of excrements from one head, kg/days; 

          n –  an amount of animals in heads;   

          t_п, t_л –  accordingly  duration of maintenance of animals in apartments and summer camps, days; t = 365 days;

          П – a loss of mass of manure in the process of its storage, %; 

         М_п  –  mass of bedding in days on one  animal / head.

On condition of the use of punching for the receipt of organic fertilizers there is mass of organic fertilizers which are made in an economy is determined after a formula:

where  - mass of organic fertilizers which are made in an economy, ò;

          - mass  of manure,  which is made in an economy, ò;

            j - type of animals;

          - mass of other organic  fertilizers.

The amount of forages (in forage units) is needed for maintenance of agricultural animals is determined after a formula:

,

where - a requirement  in fordders j to the type of animals.

An amount of forages (in forage units) got as a result of growing of agricultural plants is determined after a formula:

where - amount of forage units in 1 kg of harvest and - that  culture.

  - coefficient of commodity products (relation of mass of harvest  and - that  culture intended for a sale to general mass of harvest);

  - mass of the yeild tailings  in a harvest  and - that  culture of appointed on a forage to the animals;

  - an amount of forage units is in 1 kg of the yield tailings і   cultures.

Using mathematical dependences are higher resulted the system of equalizations which are the mathematical model of organic agriculture which takes into account the structure of sowing areas is got, structure of stock-raising of economy for the receipt of pus, mass of other organic offcuts of organogenic which can be utillized for the receipt of organic fertilizers and «Conception of biology of agriculture for a receipt ecologically clean products».

- area of plough-land, which is occupied by an agricultural culture, hectare.

The decision of this system of equalizations is an optimum structure of sowing areas of agricultural cultures and total number of livestock of cattle in an economy for the conduct of organic agriculture.

It is set that introduction of organic agriculture is possible in the economies of stock-raising direction. Certainly, that in the structure of sowing areas specific gravity of green crops is 70 % from the general area of plough-land on traditional technology of receipt of organic fertilizers. Introduction of punching for the receipt of organic fertilizers substantially changes the structure of sowing areas, where полоща under green crops diminishes from 70% to 60%, and the total number of livestock of animals in an economy does not change substantially.  

Key words: organic agriculture, manure, harvest, yield, biology of agriculture.