The balance of nutrients in soils. Nutrient balance in crop rotation

INTRODUCTION

Extended reproduction of potential and effective soil fertility is the prerequisite for ensuring continuous growth in crop yields, which is possible with a positive balance of nutrients and soil organic matter in ameliorative agriculture. In natural biocenoses, a closed cycle of biogenic elements is achieved, and in artificial agrocenoses, this cycle is broken in connection with. alienation for harvesting and significant losses of nutrients due to erosion, infiltration and volatilization. Creating the necessary conditions for a rational cycle of nutrients is the most important task of irrigated agriculture. It is possible to positively influence the effective fertility of the soil, which is understood as the provision of the soil with available nitrogen and phosphorus, as well as exchangeable potassium, to obtain the planned yields of irrigated crops is possible when carrying out balance calculations, while creating, by applying calculated doses of fertilizers, the optimal level of humus content and mobile forms of nutrients. elements in the soil.

NUTRIENTAL BALANCE CALCULATION

Nutrient balance- this is a quantitative expression of the content of nutrients in the soil on a specific area, taking into account all the items of their income (fertilizer application, natural sources, nitrogen fixation, etc.) a certain period of time. Violation of the balance of nutrients in agriculture can worsen the chemical composition of the soil, natural waters, and, consequently, plants. This, in turn, can change the quality, nutritional value of agricultural products and animal feed and lead to functional diseases in humans and animals.

Therefore, it is important to properly manage the cycle of nutrients in agriculture, create their active balance by using organic and mineral fertilizers, and prevent their loss to the environment. This is one of the most important tasks in the creation and application of landscape-adaptive systems of reclamation agriculture.

Nitrogen balance

Of particular interest is the balance of nitrogen - the main carrier of life, an element that determines the quantity and quality of the crop. The problem of nitrogen in agriculture is very relevant. This is due to the fact that nitrogen is a very mobile element and does not accumulate in the soil. Therefore, with an increase in the content of other biogenic elements, soil fertility and its cultivation in general, nitrogen will determine the size and quality of the crop. When calculating the nitrogen balance, only the main income and expenditure items are taken into account, including the supply of nitrogen with mineral, organic fertilizers and biological fixation by nodule bacteria, and the removal of nitrogen with the harvest of the main and by-products. Nitrogen balance equation:

where B a is the balance of available nitrogen, kg/ha; At D min– doses of application of mineral nitrogen-containing fertilizers in fertilizers, kg/ha; D org CA min- nitrogen content in mineral fertilizer (Appendix 4),%; SA org- nitrogen content in organic fertilizer (Appendix 5),%; In a- removal of nitrogen with the harvest of the main and by-products (Appendix 1), kg / t; AF– biological nitrogen fixation by nodule bacteria of legumes, kg/t, (assumed to be 10 kg/t of legume grass hay, 0.5 kg/t of green fodder of leguminous grass mixtures, 26 kg/t of soybean grain).

An example of nitrogen balance calculation.

Decision: The nitrogen content in manure is 0.45%, sulfoammophos is 12%; removal with a yield of 3.5 kg/t. There is no nitrogen fixation in corn ( AF =0).

kg/ha. The balance is deficient.

Phosphorus balance

Although living organisms require about 10 times less phosphorus than nitrogen, nevertheless, it is the most important biogenic element. Phosphorus is not only a source of nutrition for plants, but also an energy carrier, which is part of various nucleic acids. Phosphorus deficiency dramatically reduces plant productivity. Phosphorus has no natural sources of replenishment in the soil. It is possible to replenish its consumption for the creation of crops only by applying phosphate and organic fertilizers. In the future, the problem of phosphorus as a biogenic element in agriculture arises in the first place. In the atmosphere, phosphorus is found mainly in the form of dust in small quantities. Its cycle is simpler than the nitrogen cycle. Only soil, water and plants are involved in it in ecosystems. The availability of this element to plants is influenced by many environmental factors, so the problem of phosphorus as a biogenic element in agriculture arises first of all. Phosphorus balance is calculated by the formula:

where B f is the balance of available phosphorus, kg/ha; At– yield of cultivated crop, t/ha; D min- doses of application of mineral phosphorus-containing fertilizers in fertilizers, kg/ha; D org– doses of organic fertilizers, t/ha; CF min– phosphorus content in mineral fertilizer (Appendix 4), %; SF org– phosphorus content in organic fertilizer (Appendix 5), %; In f

An example of calculating the balance of phosphorus. In the cultivation of silage corn, 30 tons of cattle manure on straw bedding and 150 kilograms of sulphoammophos per hectare were applied. As a result, 60 t/ha of silage was obtained.

Decision: The content of phosphorus in manure is 0.23%, sulfoammophos is 39%; removal with a yield of 1.4 kg / t. kg/ha. The balance is positive.

Potassium balance

Potassium is found mainly in the mineral fine part of the soil. Its deficiency in the soil sharply inhibits the growth and development of plants. Being in them in the form of K + cation, it regulates important physiological processes, providing moisture exchange in plant cells and maintaining high activity of the cytoplasm. The potassium balance equation is:

where B to– balance of available potassium, kg/ha; At– yield of cultivated crop, t/ha; D min– doses of application of mineral potassium-containing fertilizers in fertilizers, kg/ha; D org– doses of organic fertilizers, t/ha; CC min– potassium content in mineral fertilizer (Appendix 4), %; CC org- potassium content in organic fertilizer (Appendix 5),%; VK- removal of phosphorus with the harvest of the main and by-products (Appendix 1), kg / t.

An example of potassium balance calculation. When cultivating winter wheat, 20 tons of cattle manure on straw bedding, 60 kilograms of potassium chloride and 120 kilograms of carboammophoska per hectare were introduced. As a result, 4.0 t/ha of grain was obtained.

Decision: The content of potassium in manure is 0.5%, potassium chloride 53%, carboammofoska 17%; removal with a yield of 36 kg/t.

kg/ha. The balance is non-deficit.

CALCULATION OF THE BALANCE OF HUMUS

In the soil, several multidirectional processes occur simultaneously, associated with the decomposition (mineralization), formation (humification) of humus. For targeted regulation of humus reserves in the studied soils, based on the information obtained on its content and reserves in the soils of the studied area and yield data, the humus balance is calculated. The humus balance equation has the form:

where B g - humus balance, t/ha; Y – yield, t/ha; In a– nitrogen removal per 1 ton of crop, kg/ton (Appendix 1); P P and P K– intake of stubble and root residues, respectively, t/ha; K GR and K GU - coefficients of humification of plant residues and organic fertilizers, respectively (Appendix 3); D org– dose of organic fertilizer application, t/ha; %VL- moisture content of organic fertilizer, % (Appendix 5).

The intake of stubble and root residues is determined using their regression dependences on crop yields (Appendix 2).

An example of calculating the balance of humus. When cultivating potatoes, 150 tons of cattle slurry per hectare were applied. As a result, 24 t/ha of potato tubers were obtained.

Decision: Receipt of crop residues: P P = 0,04∙24+0,1=1,06 t/ha Receipt of root residues: P to = 0,08∙24+0,8 = 1,536 t/ha Residue humification coefficient 0.35, cattle manure 0.35.

t/ha. The balance is deficient.

Change in humus content

The calculation of the initial reserves of humus in the upper 30-cm layer is carried out taking into account the density of the soil composition according to the formula:

, (5)

where ZG 0– initial reserves of humus in the upper 30 cm layer, t/ha; ρ sl- density of soil composition (Appendix 6), g / cm 3; SG 0- the initial content of humus (Appendix 6),%.

The predicted content of humus (%) is determined by the formula:

, (6)

The obtained value is compared with the range of background humus content (Appendix 7). In addition, the absolute and relative changes in the humus content are determined:

, (7)

, (8)

As a result, a conclusion is made about the significance of the changes.

An example of assessing the change in humus content. As a result of the calculation of the humus balance, it was determined that the reserves will be reduced by 36 t/ha. The soil of the irrigated area is chestnut medium loamy with an initial humus content of 2.2%. Determine the content change and its significance.

The density of the top layer of soil is 1.22 g/cm 3 . t/ha %.

This value is outside the fluctuation range of 1.8-3.0 (Appendix 8). The absolute and relative content changes are also very high: ; , which indicates an unacceptably deficient balance of soil organic matter.

Description of the execution.

1. Run Microsoft Excel.

BUT" and " ATBUT» 2-3 times.

3. To the cell " A2"Enter the word "Culture", and in the cells " A3»- « A12» rotation crop names from your option.

4. To the cell " IN 2» enter the word «Yield», and in the cells « IN 3»- « AT 12» rotation crop yields from your option.

5. To the cell " D1"Enter the word" Takeaway", in the cells " C2” – “nitrogen”; " D2" - "phosphorus"; " E2"- "potassium".

6. To the cell " F1» Enter the word «Losses» in the cell « F2"-" humus ".

7. In cells " C3»–« C12» enter formulas to calculate nitrogen carryover. To do this, pointing the cursor at the cell " C3» enter in the formula line "=В3*(хх-yy)", where хх is the value of nitrogen removal for this crop (Appendix 1); yy – biological nitrogen fixation by nodule bacteria of legumes, kg/t, (assumed to be 10 kg/t legume hay, 0.5 kg/t green fodder legume grass mixtures, 26 kg/t soybean grain). Repeat the operations for the cells " C4»–« C12».

8. Enter in the cells " D3»–« D12» formulas for calculating the phosphorus removal «=В3*хх», where хх is the value of phosphorus removal for a given crop (Appendix 1), and in the cells « E3»–« E12» similar formulas for potassium carryover.

9. In cells " F3»–« F12» Calculate the loss of humus. To do this, according to the formula given earlier, divide the nitrogen removal without taking into account the biological nitrogen fixation by nodule bacteria by 50. The formula in the cell " F3” will look like: “=В3*хх/50”, where хх is the value of nitrogen removal for this crop (Appendix 1).

10. In the cell " H1» enter the word «Remains», in the cells « G2"-" stubble"; " H2” – “root”; " I2" - "sum".

11. In cells " G3»–« G12» Calculate the input of crop residues. To do this, enter in them the formulas for the regression dependences of the mass of stubble residues on crop yields (Appendix 2), replacing "x" with a link to the corresponding cell from the yield column (cells " B3»–« B12»).

12. Similarly, calculate in the cells " H3»–« H12» supply of root residues.

13. Sum in cells " I3"–"I12» crop and root residues ( =G3+H3).

14. In the cell " J2» enter "Kg", and the cells " J3"–"J12» values ​​of humification coefficients of plant residues from Appendix 3.

15. In the cell " K1» Enter the word «Receipt», in the cell « K2"-" humus ".

16. In cells " K3»–« K12» Calculate the humus input by multiplying the humification factor by the sum of plant residues (columns G and To).

17. In the cell " L2"Enter "Bg", and in the cells " L3"–"L12» humus balances ( =K3-F3).

18. In the cell " C13» Calculate the total nitrogen removal for the entire rotation. To do this, point the cursor to this cell, click the "Insert function" button (), and select "SUM" from the list of functions. In the "Function Arguments" window that opens, specify the icon for entering the range of cells to sum () and circle the cells " C3»–« C12". Press "Enter" and then "OK" to confirm.

19. By extending the resulting formula to the cells " D13" and " E13» You will get the total removal of phosphorus and potassium.

20. To calculate the balance of humus without the participation of fertilizers, repeat the operations from paragraph 18 for the cell " L13» and range « L2-L12».

21. Enter in the cell " A16» «Fertilizer», into the cell « B16» «Dose», into the cell « D15" "Content"; into the cells C16», « D16», « E16», « F16"- "Nitrogen", "Phosphorus", "Potassium", "water".

22. In cells " A17-A22» enter the names of the applied fertilizers (first organic, then mineral).

23. In cells " B17-B22» enter the doses of applied fertilizers, for organic in tons per hectare, mineral - kilograms per hectare.

24. In cells " C17-C22» enter the nitrogen content of the fertilizer, « D17-D22"- phosphorus, " E17-E22"- potassium," F17-F22» - water (appendices 4, 5).

25. Enter in the cell " H15" "Receipt", and in the cells " G16», « H16», « I16» copy the contents of the cells « C16», « D16», « E16».

26. Calculate the intake of nutrients from organic fertilizers. To do this, in the cell G17» enter the formula "=$B17*C17*10". The sign "$" means that when the formula is distributed, the column "B" in it will not change, and the coefficient 10 is obtained by dividing 1000 (kilograms per ton) by 100 (percent).

27. Extend the formula to organic rows and columns " D" and " E».

28. Calculate the intake of nutrients with mineral fertilizers. To do this, enter the formula "=$B19*C19/100" into the cell at the intersection of the first row with mineral fertilizers and column "G".

29. Extend the formula to the rows with mineral fertilizers and the columns " D" and " E».

30. Sum up the intake of nitrogen, phosphorus and potassium in the cells " G23», « H23», « I23"(similar to paragraph 18).

31. Enter in the cell " J16» «organics», into the cell « K16» «humus».

32. Enter in the cell " J17» the formula for calculating the input of fresh organic matter into the soil: "=B17*(1-F17/100)". Extend it to all rows with organic fertilizers.

33. Enter in the cell " K17» formula for calculating the input of humus into the soil: «=J17*0.35» (0.35 is the coefficient of humification of plant residues from Appendix 3). Extend the formula to all rows with organic fertilizers.

34. Sum in the cell " K23» the entry of humus into the soil is similar to points 18 and 30.

35. Type in the cells " A24-A28» the words «Balance», «humus», «nitrogen», «phosphorus», «potassium».

36. In the cell " A25»calculate the humus balance ("=L13+K23"); in cells " A26-A28» balances of nitrogen, phosphorus and potassium using the formulas "=G23-C13", "=H23-D13" and "=I23-E13", respectively.

37. Save the workbook (file) Microsoft Excel with the name that the teacher will indicate to you. Turn off Microsoft Excel.

Description of the execution.

1. Run Microsoft Excel.

2. Open the file (book Microsoft Excel) created in Exercise 1.

3. Copy the results of the balance calculation to another sheet of the book.

4. To do this, circle the cells " A24-B28»; copy their contents to the clipboard (for example, by clicking " ctrl+c»); go to the desired sheet (list of sheets at the bottom of the table); select from the main menu " Edit» – « Special insert”, and, in the opened Paste Special window, mark the value pointer.

5. Enter in the cell " C1» «Initial stocks», into the cell « D1» Ending stocks.

6. Enter in the cell " C2» the formula for calculating the initial reserves of humus «=30*хх*yy», where хх is the density of soil composition (Appendix 6), g/cm3; yy – initial humus content (Appendix 6), %.

7. To cell " D2» Enter the formula for calculating the final (projected) humus reserves "=B2+C2".

8. Enter in the cell " E1» «Content Forecast», and in the cell « E2" formula for calculating the humus content in%: "= D2 / 30 / xx", where xx is the density of the soil (Appendix 6), g / cm 3.

9. Enter in the cells " F1" and " G1» "Absolute change" and "Relative change"

10. In the cell " F2» enter the formula for calculating the absolute change in humus content «=C2-D2».

11. In the cell " G2» enter the formula for calculating the relative change in humus content «=F2/C2*100».

12. Enter in the cells " C4" and " C5» formulas for calculating the initial reserves of available phosphorus and exchangeable potassium in the upper 30-cm layer "30*хх*yy1" and "30*хх*yy2", where хх is the density of soil composition (Appendix 6), g/cm 3 ; yy1 and yy2 are the initial content of available phosphorus and exchangeable potassium, mg per 100 g of soil (Appendix 6).

13. Enter in the cells " D4" and " D5» formulas for calculating the predicted reserves of available phosphorus and exchangeable potassium "=С4+В4" and "=С5+В5".

14. In cells " E4" and " E5» enter the formulas for calculating the predicted content of phosphorus and potassium “=D4/30/xx” and “=D5/30/xx”, where xx is the density of the soil (Appendix 6), g/cm 3 .

15. In cells " G4" and " G5» calculate the relative change in the content of available phosphorus and potassium (formulas "(yy1-E4) / yy1 * 100" and "(yy2-E5) / yy2 * 100", where the initial content of available phosphorus and exchangeable potassium, mg per 100 g of soil) .

Description of the execution.

1. Run Microsoft Excel.

2. By pointing the mouse cursor at the border between the columns " BUT" and " AT" in the line with column names, press the left mouse button and expand the column " BUT» 2 times. Repeat the operation for the column " AT».

3. To the cell " IN 2» Enter the word "Content", and in the cells " A3», « A5», « A6», « A7"–"humus", "nitrogen", "phosphorus" and "potassium".

4. To the cell " IN 3» enter the content of humus, in the cell « AT 6» phosphorus, and into the cell « AT 7» potassium from your option.

5. To the cell " C3» enter «Coverage share =», and in the cell « D3» the value of the proportion of coverage of nitrogen needs with organic fertilizers from Appendix 11.

6. To the cell " C4» enter «Xmin», in the cell « D4” – “Xmax”, into the cell “ E4” – “Kmin”, into the cell “ F4” – “Kmax”, into the cell “ G4'-'K'.

7. Enter in the cells " C6" and " C7» the lower limits of the intervals in which the values ​​of the content of phosphorus and potassium fall (Appendix 8).

8. Enter in the cells " D6" and " D7» the upper limits of the intervals in which the values ​​of the content of phosphorus and potassium fall (Appendix 8).

9. Enter in the cells " E6" and " E7» the lowest values ​​of the rotational balance coefficients for the intervals in which the values ​​of the content of phosphorus and potassium fall (Appendix 9).

10. Enter in the cells " F6" and " F7» the highest values ​​of rotational balance coefficients for the intervals in which the values ​​of phosphorus and potassium content fall (Appendix 9).

11. Enter in the cell " G5» the value of the rotational balance coefficient for nitrogen (1).

12. In cells " G6" and " G7» enter formulas for calculating the rotational balance coefficient for phosphorus and potassium (formula 18).

13. In the cell " G5» enter the rotational balance factor for nitrogen - 1.

14. In cells " A9" and " AT 9» enter the words "Crop" and "Yield".

15. In cells " A10» – « A13» enter crop names from your assignment; into the cells AT 10 O'CLOCK» – « B13- their productivity.

16. Enter in the cells " C9», « D9», « E9" and " F9» designations “AF”, “VA”, “VF” and “VK” (nitrogen fixation, nitrogen removal, phosphorus removal, potassium removal).

17. In cells " C10» – « F13» Enter the values ​​of nitrogen fixation (note to formula 1) and removal of nutrients for all crops (Appendix 1).

18. Enter in the cell " A15» the word «Fertilizers», and in the cells « B15», « C15" and " D15» the designations "Ca", "Sf" and "SK" (the content of nitrogen, phosphorus, potassium).

19. In cells " A16» – « A19» enter the names of fertilizers from your task option; into the cells B16» – « D19» - the content of batteries in them (appendices 4 and 5).

20. Copy " D9», « E9" and " F9» to cells « G9», « H9», « I9».

21. In the cells " G10» – « G13» Calculate nitrogen carryover with crop yield (formula for row 10: "=B10*(D10-C10)").

22. In the cells " H10» – « H13" and " I10» – « I13» Calculate phosphorus and potassium removals with yield (formula for phosphorus and line 10: "=B10*E10"; potassium and line 10: "=B10*F10").

23. Enter in the cells " J9», « K9», « L9» designations "Doa", "Dof" and "Doc" (total doses of fertilizers for each main nutrient in kilograms of active ingredient).

24. In the cells " J10» – « L13» Calculate total fertilizer doses for each major nutrient (e.g. for « J10"-"=G10*$G$5").

25. In the cell " M9» enter the designation “Dorga” (dose of organic nitrogen), and in the cells “ M10» – « M13» Calculate this dose using Equation 19.

26. In the cell " N9» enter the designation "Dorg" (dose of organic fertilizer), and in the cells " N10» – « N13» Calculate this dose using Equation 20.

27. In the cell " O9» enter the designation “Dorgo” (the dose of organic fertilizer is rounded), and in the cells “ O10» – « O13» - doses of organic matter for each crop, rounded up to 5 t/ha.

28. Type in the cells " P9», « Q9», « R9» the designations “Dorga”, “Dorgf” and “Dorgk” (kilograms of the active substance for each main nutrient contained in organic fertilizer).

29. Calculate the doses of nutrients in organic fertilizer. To do this, enter in the cell " P10» the formula "=10*$O10*B$16", and then spread it to the cells " P10» – « R13».

30. Enter in the cells " S9», « T9», « U9» designations "Dma", "Dmf" and "Dmk" (kilograms of the active substance for each main nutrient, which must be applied with mineral fertilizer).

31. In the cells " S10» – « U13» Determine these doses as the difference between the total need for a nutrient and its content in organic fertilizer. To do this, enter in the cell " S10" formula =J10-P10", and then extend it to the cells " S10» – « U13».

32. Enter in the cells " V9», « W9», « X9» designations "MA", "MF" and "MK" (doses of nitrogen, phosphorus and potassium mineral fertilizers in natural fertilizers, kg).

33. In the cells " V10» – « X13» determine these doses using formulas: for nitrogen fertilizer – “=S10*100/B$17”; phosphoric - "=T10*100/C$18"; potash - "=U10*100/D$19".

34. Mark cells " V10» – « X14” and round them to integers (menu items “Format” - “Cells” - “Number”). In the window that opens, select the "Numeric" format and specify the number of decimal places - 0.

35. In the cells " O14», « V14», « W14», « X14» Use the SUM function to calculate the total fertilizer application rates.

LITERATURE

1. Kravchuk A.V., Muravlev A.P., Prokopets R.V., Donguzov G.S. Fundamentals of rational nature management: guidelines and materials for laboratory and practical classes. – Saratov: Saratov State Agrarian University named after N.I. Vavilova, 2004. - 47 p.

2. Kravchuk A.V., Shavrin D.I., Prokopets R.V. Guidelines for the implementation of course work in the discipline "Nature management" - Saratov: Federal State Educational Institution of Higher Professional Education "Saratov State Agrarian University named after N.I. Vavilov", 2013. - 20 p.

3. Leontiev S.A., Chumakova L.N., Prokopets R.V., Arzhanukhina E.V., Nikishanov A.N. Natural and technogenic complexes of environmental management: guidelines for the implementation of the course project - Saratov: FGOU VPO "Saratov State Agrarian University named after N.I. Vavilov", 2012. - 40 p.

4. Prokopets R.V. Influence of irrigation erosion on the loss of nutrients in the soil // Problems of scientific support of agricultural production and education: collection of articles. scientific works - under the general editorship of A.V. Kravchuk. - Saratov, 2008. - S. 183-188.

5. Prokopets R.V. Removal of nutrients with surface runoff on dark chestnut soils during irrigation of eastern goat's rue // Vavilov Readings 2006: Proceedings of the conference dedicated to the 119th anniversary of Academician N.I. Vavilov. – Saratov: Federal State Educational Institution of Higher Professional Education “Saratov State Agrarian University named after V.I. N.I. Vavilov", 2006. - S. 72-73.

6. Prokopets R.V. Removal of nutrients with solid runoff on dark chestnut soils during irrigation of eastern goat's rue // Systemic studies of natural and technogenic complexes of the Lower Volga region: coll. scientific works. - Saratov, 2007. - S. 124-127.

7. Prokopets R.V., Arzhanukhina E.V., Shavrin D.I., Zavadsky I.S. Planning of environmental measures: guidelines for the implementation of settlement and graphic work - Saratov: FGOU VPO "Saratov State Agrarian University named after N.I. Vavilov", 2012. - 29 p.

8. Prokopets R.V., Chumakova L.N., Arzhanukhina E.V., Shavrin D.I., Zavadsky I.S. Management of reclamation water management systems using computer technology: guidelines for laboratory work. – Saratov: FGOU VPO “Saratov State Agrarian University named after N.I. Vavilov", 2012. - 26 p.

9. Pronko V.V., Korsak V.V., Druzhkin A.F. Influence of weather conditions and agricultural practices on the effectiveness of fertilizers in the steppe Volga region // Agrochemistry, 2004, No. 8, pp. 20-26.

10. Pronko N.A., Korsak V.V. Method for calculating the doses of organic and mineral fertilizers for crops of irrigated crop rotations according to the predicted rotational balance of nutrients // Agrochemistry, 2001, No. 7, P. 66-71.

11. Pronko N.A., Korsak V.V., Korneva T.V. Features of dehumification of irrigated dark chestnut soils of the Saratov Trans-Volga region // Bulletin of the Saratov State Agrarian University. N.I. Vavilov. - 2009. - No. 10. - P. 42-46.

12. Pronko N.A., Korsak V.V., Prokopets R.V., Korneva T.V., Romanova L.G. Calculation of balances of humus and plant nutrients in ameliorative agriculture using information technology / Guidelines for the implementation of coursework and laboratory work. - Saratov, FGOU VPO "Saratov State Agrarian University", 2010, 39 p.

13. Pron'ko N.A., Korsak V.V., Falkovich A.S. Irrigation in the Volga region: do not repeat mistakes. - Melioration and water management, 2014, No. 4, pp. 16-19.

14. Pronko N.A., Falkovich A.S., Romanova L.G. Changes in the fertility of irrigated chestnut soils in the Volga region during long-term use and the scientific basis for its regulation. Saratov: SSAU, 2005, 220 p.

APPS

6. Soil density, humus content and available nutrients in the upper 30 cm layer

Variants of initial data for calculating the balance and changing the content of humus and nutrients

Nutrition should be organized in such a way that it ensures the harmonious development and well-coordinated activity of the body. To do this, the diet should be balanced in quantity and quality with the needs of a person, according to his profession, age, sex. The physiological needs of the body depend on many conditions. Most of these conditions are constantly changing, so it is almost impossible to accurately balance nutrition for every moment of life. But the body has special regulatory mechanisms that allow it to use from the food taken and absorb the necessary nutrients in the amount that it needs at the moment. However, the regulatory adaptive abilities of the body have certain limits: they are limited in childhood and old age. In addition, many nutrients, for example, some vitamins, essential amino acids, the human body is not able to form in the process of metabolism, they must be supplied with food, otherwise diseases associated with malnutrition occur.

Properties of nutrients and the need for them in the body
With food, the body receives the proteins, fats, carbohydrates necessary for life, as well as biologically active substances - vitamins and minerals, salts. The amount of energy released during the assimilation of a particular food product by the body is called the calorie content of this product. The need for various nutrients and energy depends on gender, age and the nature of work. For the correct preparation of the diet, taking into account the nature of work, specialists in the field of food hygiene divide the entire adult population into 4 groups. The first group includes persons whose work is not associated with the cost of physical labor or requires little physical effort: mental workers, control panel workers, dispatchers and others whose work is associated with a certain nervous tension, all employees. The second group includes workers in mechanized production and service workers, whose work does not require a lot of physical. voltage: nurses, nurses, salesmen, conductors, conductors, workers in the radio-electronic industry, signalmen, telegraph operators, sewers, workers employed in automated processes, etc. To the third - workers in industries with a partially mechanized labor process and workers in the service sector whose labor associated with significant physical stress: machine operators, textile workers, shoemakers, drivers of metro trains, buses, trams, trolleybuses, postmen, laundries and catering workers (except for the administrative and managerial apparatus), agronomists and foremen of tractor and field farming teams, etc. To the fourth - workers in semi-mechanized or non-mechanized industries of medium and heavy labor: miners, miners, truck drivers, metallurgists, blacksmiths, the bulk of agricultural workers and machine operators, workers employed in logging, etc. Persons whose work is associated with a large nervous tension (r Employees of control panels, dispatchers, etc.) are equated to group I of labor intensity in terms of energy and protein requirements, and to group III in terms of vitamin requirements. In addition, for some contingents of the population, special standards have been established. Thus, the need for calories in men engaged in especially heavy manual labor (diggers, loaders, lumberjacks, etc.) is 4500 kcal, for students - 3300 kcal, for female students - 2800 kcal.

The correct preparation of an individual diet is possible only with knowledge of the chemical composition of food products.

Squirrels
Proteins are the most important part of food. Protein deficiency in nutrition is one of the reasons for the increased susceptibility of the body to infectious diseases. With an insufficient amount of proteins, hematopoiesis decreases, the development of a growing organism is delayed, the activity of the nervous system, liver and other organs is disrupted, cell recovery after serious illnesses is slowed down. Excess protein in the diet can also harm the body.

In the norms of nutrition adopted in the USSR, it is recommended that in the diet due to protein, an average of 14% of total calories was provided. Vegetable products - cereals, legumes, potatoes - are a valuable and important source of providing the body with proteins. However it is necessary that in the daily diet vegetable proteins make up no more than 40%.

Nitrogenous extractive substances contained in meat, fish and mushrooms are of great importance in nutrition. Meat and fish broths, mushroom decoctions, due to the presence of extractive substances in them, help to improve digestion, causing increased secretion of digestive juices. At the same time, nitrogenous extractive substances in connection with the content of the so-called. purine bases require enhanced liver function.

Carbohydrates
Over half of the energy needed for normal life, the human body receives from carbohydrates. They are found predominantly in plant foods. A large amount of carbohydrates in the form of starch is found in bread, cereals, potatoes, and in the form of sugars - in sugar, confectionery, sweet varieties of fruits and berries. Carbohydrates are extremely important for the functioning of the muscles, nervous system, heart, liver and other organs.

Carbohydrates play a certain role in metabolic processes. They are necessary for the normal absorption of fats by the body. But excess sugar intake, combined with a general high-calorie diet, can lead to obesity, early development of atherosclerosis, and decreased performance. Excessive intake of sugar is especially unfavorable for elderly people, in whom excess sugar can contribute to the progression of the atherosclerotic process. In addition to these negative consequences, excessive intake of sugar can lead to hyperglycemia (high blood sugar), which adversely affects the function of the pancreas.

In a normal diet, carbohydrates should be approximately 4 times more than proteins. The need for carbohydrates is determined by the amount of energy costs. The more intense the physical activity, the greater the amount of muscle work, the higher the need for carbohydrates. Elderly people, as well as people engaged in mental work and overweight, it is recommended that the amount of sugar ingested daily does not exceed 15% of the total daily amount of carbohydrates.

Rationing of carbohydrates can be carried out according to the caloric value of the daily diet. At the same time, 124 g of carbohydrates are provided for every 1000 kcal. Pure sugar (in jam, honey, sweets and confectionery), quickly absorbed in the intestines, causes a number of unpleasant sensations in some people: increased sweating, nausea, followed by lethargy, weakness, up to a fainting state, etc. These phenomena are explained by the fact that the amount of sugar in the blood increases rapidly and sharply, and then falls sharply, as a result of which the nervous system is excited. Therefore, you should not consume more than 100 g of sugar and sugary, including confectionery, products per day.

Twice a day, a dish of cereals, pasta or legumes, a dish and a side dish of potatoes or vegetables, 400-500 g of bread and about 90-100 g of sugar and sweets fully provide the daily carbohydrate requirement of an adult.

In vegetable products, along with carbohydrates that provide the body with energy, so-called non-food carbohydrates are contained - cellulose. It has no practical significance as a source of energy in the diet, assimilated by about 25%, but contributes to the normal function of the intestines: by irritating the walls of the intestines, it causes their movement - peristalsis. When eating food devoid of fiber, peristalsis weakens, which contributes to constipation.

Gray wheat bread, rye bread, vegetables should be included in the menu every day. Raw vegetables and fruits are very useful; they are also valuable because they contain so-called pectin substances. Being carbohydrates, pectins have some nutritional value. However, their main importance for digestion is that they contribute to better emptying of the intestines, increasing its peristalsis.

Fats
Fats are a ready-made "combustible" material that supplies the body with energy. Fats are necessary to ensure the normal absorption of proteins, certain minerals, salts, and fat-soluble vitamins by the body. The presence of fats in food gives various dishes high palatability, stimulates appetite, which is essential for normal digestion.

The fats that come with food are partly used to create fat reserves. Satisfaction of the need for fat and all its components depends on the type and quality of fat - the complementarity of animal and vegetable fats has been established. Biologically optimal balance is created when 70-80% animal fats and 20-30% vegetable fats are included in the daily diet.

The norms of fat intake into the body are calculated taking into account age, the nature of work, national characteristics and climatic conditions. The dietary norms recommended for the population of the USSR provide for 30% of calories in the daily diet from fat. Normalization of fat can be carried out according to the caloric value of the daily diet. At the same time, 35 g of fat is provided for every 1000 kcal. Of certain importance is the qualitative composition of fats included in the diet. Fats of various animals, birds and fish, milk fat (ch. arr. butter or ghee), as well as vegetable fats (sunflower, soybean, peanut, olive and other oils) are used for food.

Vegetable fats should be included daily in the diet for 20-25 g. Together with vegetable fats, beef and lard, and especially butter, should be included in the diet. Animal fats should be in the daily diet of about 75-80 g (of which 40 g in its natural form, and the rest - in various foods). The composition of the diet also includes certain fat-like substances - cholesterol and lecithin. Cholesterol, to-ry is contained in a significant amount in animal fats, egg yolks, caviar, brains, liver, kidneys, plays an important role in the life of the body, in particular in the activity of the nervous system.

Lecithin, due to the content of phosphorus and choline in it, is a biology, cholesterol antagonist. It stimulates the development of a growing organism, favorably affects the activity of the nervous system, liver, stimulates hematopoiesis, increases the body's resistance to toxicity. substances, improves the absorption of fats, prevents the development of atherosclerosis. A significant amount of lecithin is found in buckwheat, wheat bran, lettuce. A lot of lecithin in soy, beans and other legumes.

mineral salts
Minerals are part of all the tissues of our body and are constantly consumed in the process of vital activity of the body. The daily human need for mineral salts is different. So, the daily need for sodium chloride (table salt), calcium phosphate is calculated in grams, the daily need for salts of copper, manganese, iodine is calculated in milligrams. Finally, there are such mineral salts, the daily requirement for which is calculated in thousandths of a milligram - micrograms. The body's need for mineral salts is usually fully met with a varied diet.

Among the various mineral salts that a person receives with food, table salt occupies a significant place. Insipid food, even the most varied, quickly becomes boring and disgusting. In addition, table salt is necessary to maintain a normal amount of fluid in the blood and tissues, it affects urination, the activity of the nervous system, blood circulation, and is involved in the formation of hydrochloric acid in the glands of the stomach.

In total, the body contains about 300 g of salt, and a person eats about 5.5 kg of salt per year. In addition to 3-4 g of salt contained in natural foods of the daily ration, a few grams of salt are eaten with bread (100 g of rye bread contains about 1.5 g of it, and 100 g of wheat bread - 0.5-0, 8 g), a few grams are added when cooking food. On average, you should consume up to 12 g of salt per day. The bone skeleton is approx. 1/5th of the weight of the human body, and 2/3 of the bones are composed of mineral salts. Bone tissue contains about 99% of all calcium present in the human body. However, the rest of the calcium plays an important role, participating in a wide variety of metabolic processes. Calcium salts are present in almost all food products, but are not always absorbed by the human body. To provide the body with the necessary amount of calcium salts, it is necessary to include in the diet products that contain a significant amount of calcium that is well absorbed by the body. Such products include milk, lactic acid products, cheese, egg yolk.

Phosphorus plays an important role in the life of the organism. In addition to participating in the formation of bone tissue, a significant amount of phosphorus is part of the nervous tissue, so it is necessary for the normal functioning of the nervous system. Phosphorus salts are found in almost all food products of both plant and animal origin; a lot of phosphorus is found in nuts, bread, cereals, meat, brains, liver, fish, eggs, cheese, milk.

Magnesium salts are of great importance for the normal functioning of the cardiovascular system. They are especially necessary in old age, because they contribute to the removal of excess cholesterol from the body. A lot of magnesium salts are found in bran, and, consequently, in wholemeal bread, in buckwheat and barley groats, in sea fish.

Potassium is especially important for ensuring the normal functioning of the cardiovascular system, since it enhances urination. Melon vegetables (pumpkin, zucchini, watermelon), apples, dried apricots, raisins, containing a lot of potassium salts, are recommended for people suffering from heart disease, hypertension.

The body's need for gland and copper is very small and amounts to thousandths of a gram per day, but these elements play an extremely important role in hematopoiesis. The body's need for iodine is also insignificant, but its absence in food products leads to disruption of the thyroid gland and the development of the so-called. endemic goiter. To prevent the development of this disease, a certain amount of iodine salts is added to table salt, which is supplied to the population of areas where the soil and water do not contain iodine. A lot of iodine salts contain sea fish (cod, flounder, sea bass) and seafood (seaweed, squid, crabs, shrimp, etc.).

Cobalt salts , which belongs to trace elements, play an important role in hematopoiesis, since cobalt is part of vitamin B12. In significant quantities, they are found in peas, beets, red currants, strawberries.

Water refers to substances that do not form energy when used in the body, but life is impossible without water.

When the correct amount of liquid is introduced into the diet, the proper volume (weight) of food is ensured, which creates a feeling of satiety. Average daily water requirement is approx. 35-40 ml per 1 kg of body weight, i.e. approx. 2.5 l. A significant part of this norm (approx. 1 l) is contained in food products: for example, in cereals - up to 80% water, in bread - about 50%, in vegetables and fruits - up to 90%. The so-called free liquid contained in soup, compote, milk, tea, coffee and other drinks should be about 1.2 liters with a total daily ration weight of approx. 3 kg. The amount of water introduced into the body with food and drink varies depending on climatic conditions and the degree of intensity of physical work.

vitamins are an essential and indispensable part of the diet. They ensure the normal functioning of the body, participate in the process of assimilation of other nutrients, help to increase the body's resistance to various harmful environmental influences, and increase the working capacity of a person.

A varied composition of food products in the diet and proper culinary processing of food contribute to the preservation of vitamins. With heavy physical labor, pregnancy, those living in the northern regions need for vitamins increases. In such conditions, there is a need to use vitamin preparations.

The assimilation of food depends on the type of product and on how varied the diet is. Foods of animal origin are better digested, while the digestion of proteins is of primary importance. The proteins of meat, fish, eggs and dairy products are absorbed better than the proteins of bread, cereals, vegetables and fruits. The most important factor in proper nutrition is the variety of food. Monotonous food becomes boring and less digestible. When eating meat, bread and cereals, an average of 75% of the proteins contained in them are absorbed, and when vegetables are added, digestibility increases to 85-90%. Correct, sufficient heat treatment of products and their grinding significantly increase the digestibility of nutrients.

The diet includes the following concepts:

1) the number of meals,

2) intervals between meals,

3) the distribution of daily caloric intake between individual meals. The most rational is four meals a day, which creates a uniform load on the digestive tract and ensures the most complete processing of food by digestive juices. Eating at the same time develops a reflex for the most active secretion of gastric juice at the set time. The distribution of the daily ration with four meals a day is made depending on the daily routine and established habits. In any case, the last meal should be at least 2-3 hours before bedtime. The most appropriate is the following distribution of the diet: breakfast - 25%, lunch - 35%, afternoon tea - 15%, dinner - 25%. When working on a night shift, 2-3 hours before work, dinner should be 30% of the daily ration and, in addition, meals are provided in the 2nd half of the night shift.

The temperature regime of food is also important for normal digestion. Hot food should have a temperature of 50-60 °, cold dishes - not lower than 10 °.

Nutrition for the elderly
In persons aged 60 years and older, metabolic processes become less intense. Associated with this is a change (compared to persons of mature age) in the need for caloric content of food and the amount of proteins, fats and carbohydrates received.

In the diet of the elderly, it is recommended to significantly limit or exclude from the diet strong meat broths, mushroom decoctions, spicy seasonings, both in order to create sparing conditions for the organs of the digestive, cardiovascular and urinary systems, and to normalize water-salt metabolism; limit foods containing a significant amount of cholesterol (egg yolk, caviar, brains, liver, etc.) and refractory fats (lamb, lard, etc.). The required amount of animal proteins and fats should come from dairy products. It is highly desirable to include vegetables and fruits in the diet of the elderly, especially in fresh, raw form. It is also necessary to limit the amount of table salt. Older age requires a more careful attitude to the diet, but you should not drastically change the usual regimen, it is important to observe the usual meal times.

Nutrition for pregnant women and nursing mothers
During pregnancy, the need for proteins, and partially for fats, calcium, and phosphorus increases. Depending on the nature of work and body weight, a pregnant woman should receive from 100 to 120 g of easily digestible and complete protein per day, of which approximately 65 g should be animal protein. The main sources of protein are milk, cottage cheese, cheese, fish and meat, and meat should be consumed lean, preferably boiled. Daily intake of milk provides the body of a pregnant woman with the necessary amount of protein, calcium and phosphorus. The nutrition of a pregnant woman must be enriched with vitamins. A pregnant woman also needs an increased intake of iron. The liver, egg yolk, greens, fruits are especially rich in them. During pregnancy, you should avoid the use of excess amounts of table salt; women who are predisposed to be overweight should limit their intake of fats and carbohydrates.

During the period of feeding a child, a woman should receive more abundant nutrition than during pregnancy. The calorie content of the diet should be increased, and the amount of protein should be at least 130 g, including at least 80 g of the animal. You should increase the amount of milk you drink, eat more eggs, butter, cheese, vegetables, fruits. A lactating woman should monitor her weight, which by the end of the second month after childbirth should return to pre-pregnancy weight and remain stable throughout the entire feeding period.

Baby food
The child's food should contain the same nutritional and biologically active substances that are included in the diet of an adult, however, their ratio and the selection of products - sources of these substances - must correspond to the age of the child. Insufficient or excessive in quantity, defective in quality nutrition adversely affects the physical and mental development of the child.

An increased basal metabolism and high (due to a mobile lifestyle) energy expenditure in children require sufficient intake of protein and high-calorie foods.

In the nutrition of young children, the ratio of proteins, fats, carbohydrates should be 1: 1: 3, of older children - 1: 1: 4, a large proportion of animal products is provided.

The share of protein of animal origin in the diet of young children is 70-80%, of school age - 60-65% of the total amount of protein. Such an intake of animal protein is ensured by the inclusion of meat, fish, eggs, and milk in sufficient quantities in baby food. The daily ration of toddlers should include at least 600-800 ml of milk, the diet of a schoolchild - 400-500 ml. The importance of fats in the nutrition of children is varied - they provide the assimilation of vitamins A and D, the intake of polyunsaturated fatty acids and phosphatides necessary for the body. Excessive fat content in the diet negatively affects the development of the body - metabolism is disturbed, protein utilization worsens, digestion is disturbed, and overweight appears. Children's need for fats should be met mainly by butter and dairy products.

Carbohydrates are essential for children as they are a good source of energy. Of particular importance are easily digestible carbohydrates, which are found in berries, fruits and products of their processing, milk contains an indispensable carbohydrate for children - lactose. However, one should also remember the negative impact of excessive intake of carbohydrates (above physiological norms) on the child's body, which manifests itself in metabolic disorders, reduced resistance to diseases, and obesity.

Sufficient and varied vitamin and mineral composition of food is important in the nutrition of children. The main sources of these vital substances are fresh vegetables and fruits, milk and dairy products, as well as meat and fish products, fats, cereals and bakery products.

One of the main requirements of rational child nutrition is strict adherence to the diet. At preschool age, it is recommended to eat at least 5 times a day, i.e. every 2-3 hours, and breakfast should be 20-25% of the daily calorie content, second breakfast - 15%, lunch - 25-30%, afternoon snack - 15%, dinner - 20-25%. For school-age children, four meals a day are recommended, and breakfast should be 25% of the daily calorie content, lunch - 30%, afternoon tea - 20% and dinner - 25%.

Nutrition of children is an essential health factor. Its proper organization is important in preschool institutions, as well as in schools. A prerequisite is to provide schoolchildren with hot breakfasts, and extended day groups - and lunches.

Therapeutic and preventive nutrition
In our country, a list of professions and industries has been approved, which provides for the issuance of free therapeutic and preventive nutrition, which helps to strengthen the body and increase its resistance to adverse environmental factors, normalize metabolism and improve the functioning of organs and systems that are most at risk when exposed to harmful chemical or physical production factors, a decrease in absorption from the gastrointestinal tract and an increase in the excretion of a toxic agent from the body.

In accordance with these tasks, special diets have been developed, lists of food products have been compiled, and norms for the issuance of vitamin preparations have been established, depending on adverse production factors affecting the body. Ration No. 1 is intended for persons employed in production, where there are sources of ionizing radiation. Ration No. 2 is intended for persons involved in the production of fluorine compounds, chromium oxides, nitric and sulfuric to-t, cyanide compounds. Ration number 3 is intended for workers who have contact with lead. Ration No. 4 is intended for persons working with compounds of arsenic, phosphorus, tellurium, nitro- and amino compounds, chlorinated hydrocarbons, etc. Ration No. 5 is designed for working industries where the body of workers is exposed to compounds of tetraethyl lead, carbon disulfide, thiophos, barium compounds and manganese.

In some industries, free additional issuance of vitamins is provided. So, when exposed to fluorine, chlorine, chromium, cyanide compounds and alkali metals, vitamin A (2 mg) is obtained, when exposed to arsenic, tellurium, tetraethyl lead, bromine hydrocarbons, carbon disulfide, thiophos, mercury, manganese - vitamin B (4 mg) . Workers exposed to high temperature, significant heat radiation, employed in the baking industry and shag production, should receive daily vitamins A (2 mg), B4 (3 mg), B2 (3 mg), C (150 mg), PP (20 mg ).

The preparation and distribution of therapeutic and preventive nutrition is carried out in canteens of industrial enterprises or, by agreement with the administration, in special dietary canteens.

"Popular Medical Encyclopedia"
Editor-in-Chief Academician B.V. Petrovsky
Moscow "Soviet Encyclopedia" 1979

Accounting for the balance of nutrients is the basis for regulating the processes of plant nutrition and increasing soil fertility. For many years there was an opinion that the use of fertilizers should be calculated only for the direct nutrition of plants. It was mainly recommended to carry out various top dressings, fractional fertilization at different periods of plant development. Even for the future, the task was not set to increase the content of phosphorus, potassium and other nutrients in the soil with the help of fertilizers. Such an approach to the problems of chemicalization did not allow revealing the true need for chemical fertilizers necessary for the expanded reproduction of soil fertility. At the same time, experience shows that even a significant increase in the amount of fertilizer applied on acidic, uncultivated soils with a low nutrient content does not provide not only maximum, but average stable crop yields.
Since 1965, with the creation of the state agrochemical service, systematic control has been carried out in the Tomsk region, which traces the dynamics of changes in soil fertility. The study of the dynamics of nutrients in the soil and the balance makes it possible to control, purposefully regulate the agrochemical properties of soils and increase the efficiency of fertility through the use of fertilizers, chemical ameliorants and other means.

In intensive crop production, it is necessary to ensure a deficit-free balance of organic matter in the soil, which is a prerequisite for maintaining and increasing its natural fertility. To achieve this, it is necessary to use all possible sources of organic matter entering the soil - manure, urea, green manure, various composts, bird droppings, straw, root and stubble residues, pond silt, lake sapropel, and the like. Of course, the main source of return of organic matter to the soil is manure and nutrient and root residues of crops. On average, 1 ton of bedding manure gives about 30 kg of humus.

The introduction of organic and mineral fertilizers improves the quality of humus, which is determined by the ratio of humic and fulvic acids. If this ratio is greater than one, the humus is of high quality, and the type of humic substances is humate-fulvate, if more than two - humate.

Humic substances should be sticky and contain calcium. Fresh humic substances, primarily calcium humates, ensure the water resistance of the soil structure.

The maximum crop yields are obtained, as a rule, when organic and mineral fertilizers are applied, as this contributes to a more efficient use of fertilizer and soil nutrients. Of course, there may be exceptions. For example, the nutritional needs of white wheat sown after sweet clover are fully satisfied; in this case, it is possible to do without applying mineral fertilizers.

The introduction of complete mineral, organic and organo-mineral fertilizers provides an increase in the yield of almost all crops. At the same time, there is no consensus on the advisability of applying increased and even normal norms of mineral nitrogen fertilizers for legumes, in particular, for alfalfa, sainfoin, clover, peas, spring vetch, sweet clover, etc. It is believed that even small doses of nitrogen (N 40-60 ) inhibit the activity of nodule bacteria. It is also clear that it is impossible to achieve high yields only due to nitrogen fixation. So, in the studies of M. Yu. Khomchak, A. I Zinchenko, M. T. Dzyugan at the Uman State Agrarian Academy, V.P. nitrogen was up to 120 kg / ha.

In the Forest-Steppe, with the introduction of phosphorus-potassium fertilizers (sometimes without them), alfalfa yields were 300-320 centners / ha, nitrogen - 420-480 centners / ha, on irrigated lands - 460-480 and 650-800 centners / ha, respectively. 750-800 c/ha of alfalfa green mass was collected on irrigated areas in the farms of the Shpolyansky district of the Cherkasy region with the introduction of high nitrogen rates (250-300 kg/ha of the active substance), introducing it under each mowing in the form of ammonia water. In studies by A.I. Zinchenko, M.Yu. Khomchak in the state farms "Babansky" of the Uman region, with the introduction of 150-160 kg / ha of nitrogen in the spring, the yield of alfalfa reached 440 centners / ha only for the first mowing.

So, nitrogen fertilizers should be an integral part of growing technologies for leguminous and legume fodder grasses, with the exception of fields where before sowing (for example, alfalfa) a sufficient amount of organic fertilizers was applied under autumn plowing or under the predecessor.

With a concentration of livestock on the farm of more than 100 conditional heads and utilization of last year's straw, manure production can be increased to 14-16 t / ha. Together with other sources of organic matter, this will provide increased yields and a direct or low nutrient balance in the soil. Under these conditions, the application of mineral fertilizers for all crops of the crop rotation will be of auxiliary importance.

It not only has a great impact on increasing the yield of agricultural crops, but also helps to increase the potential fertility of the soil. The nature of these changes is closely dependent on the emerging balance of the main nutrients in agriculture: compounds of phosphorus, nitrogen and potassium. With a positive balance, i.e. when the input of nutrients into the soil exceeds their removal with the harvest, there is an increase in soil fertility, with a negative - a decrease.

During the period of intensive agriculture, the balance of nitrogen, phosphorus and potassium in Russia as a whole developed positively, and a gradual accumulation of nutrients in arable soils was observed almost everywhere. The rates of this accumulation differed markedly across the country's zones and were the highest in the Non-Chernozem zone.

In the zone of distribution of soddy-podzolic soils, the compensation for the removal of phosphorus by the harvest in the amount of 1971-1990. amounted to 44.2%, or more than 800 kg/ha P2O5 was applied in excess of the removal. As a result, the weighted average content of mobile phosphorus increased from 62 to 137 mg/kg of soil, or more than 2 times. On gray forest soils, the introduction of phosphorus over the same period exceeded the removal with the yield by almost 500 kg/ha, which made it possible to raise the weighted average content of P2O5 from 57 to 112 mg/kg. An increase in the reserve of mobile phosphorus was also noted on chestnut soils, but in a somewhat smaller amount.

At present, when the use of fertilizers in the country has sharply decreased, prerequisites have been created for the reverse process: the depletion of soils in nutrients.

To assess the size and speed of this process, information on the balance of nutrients in agriculture in various soil-climatic zones and regions of the country is of interest. Agrochemical inspection of specific areas is not carried out annually, but periodically - once every 5-10 years. In order to get an idea of ​​the possible changes in soil nutrient content that can occur between survey cycles, an annual determination of the crop nutrient balance is required. This will make it possible to predict the direction of changes in the agrochemical properties of the soil and give scientifically substantiated recommendations for the preservation or improvement of soil fertility, the rational use of limited fertilizer resources.

The initial information for determining the balance of nitrogen, phosphorus and potassium is statistical data on the application of mineral and organic fertilizers, data on the yield and gross harvest of cultivated crops, data on the structure of sown areas.

In the expenditure part of the balance, the removal of nutrients with the harvest of all agricultural crops cultivated on arable soils was taken into account, in the income part - the influx of nitrogen, phosphorus and potassium with mineral and organic fertilizers.

Due to the wide variety of soil-climatic and organizational-economic conditions in Russia, the situation in each region develops differently, therefore, the balance was determined in the agriculture of all subjects of the Russian Federation.

An analysis of the balance of nutrients in Russian agriculture in 2001 indicates that its main feature is a pronounced deficit character. One of the reasons for this is the very low level of application of mineral and organic fertilizers. On average in the country in 2001, 12 kg of mineral fertilizers of nitrogen, phosphorus, potassium were applied per 1 ha of arable land, and together with organic fertilizers - 21.4 kg.

The smallest amount of fertilizers was used in Siberia: 5.1 kg/ha on average, with deviations from 0.1 kg/ha in the Tyva Republic to 14.3 kg/ha in the Krasnoyarsk Territory.

With the current level of fertilizer use, the deficit of nitrogen in the Russian Federation as a whole in 2001 amounted to 24.6 kg/ha, phosphorus - 6.6 kg/ha and potassium - 33.6 kg/ha, or in total - 64.8 kg / ha. None of the constituent entities of the Russian Federation had a positive balance for any element.

An assessment of the balance of nutrients by its intensity showed that, in general, in the Russian Federation, the replacement of nitrogen removal with the crop amounted to 32%, phosphorus - 38% and potassium - 15%.
According to the founder of agrochemistry in Russia D.N. Pryanishnikov, in order to maintain soil fertility and increase yields, it is necessary to return to the fields at least 80% of the nitrogen consumed by crops, 100% of phosphorus and 70-80% of potassium in the form of organic and mineral fertilizers.

According to the State Agrochemical Service of the Russian Federation as of January 1, 2001, 53 million hectares, or 42.6%, have a low humus content; 36.7 million hectares of arable land, or 31.7% - increased acidity; 24.2 million ha, or 19.5% - low content of mobile phosphorus and 11.2 million ha, or 9% - low content of exchangeable potassium. For the period 1992-2001. the sown area in Russia decreased by 29.2 million hectares, or 25.5%, including for grain crops - by 16.3 million hectares, or 26.3%; fiber flax - by 219 thousand hectares, or 2 times; sugar beet - by 633 thousand hectares, or 44%; fodder crops - by 13.4 million hectares, or 31.5%.