Modern problems of science and education. Features of the formation of crop rotations Saturation of crop rotations with grain crops

V. P. Williams in the thirties of the XX century. narrowed the concept of a farming system. He understood the agricultural system as only a way to restore soil fertility due to the presence of active humus and a strong soil structure. His definition missed the economic side of the farming system. V. R. Williams mistakenly believed that in a socialist state there should be only one farming system - grass, and he considered the task of increasing soil fertility very narrowly - only by creating a strong soil structure.

D. N. Pryanishnikov, in contrast to V. R. Williams, noted that farming systems should be distinguished by the way the land is used by certain agricultural crops (cereals, fodder, industrial crops, etc.), depending on the specialization of the farm.

In the modern concept, a farming system is a form of farming that represents a complex of interrelated agrotechnical, reclamation and organizational measures, characterized by the intensity of land use, methods of restoring and increasing soil fertility.

The main features of farming systems are the ways of using the land and maintaining and increasing soil fertility. The method of land use is characterized by the ratio of land and the structure of crop areas, the area sown with agricultural crops and arable land on the farm, and the method of increasing effective soil fertility is characterized by the intensity of the applied complex of agrotechnical and reclamation measures.

The most important task of modern agriculture is to prevent a decrease in yield and quality of grown products due to a sharp reduction in the use of mineral fertilizers and pesticides. They are currently too expensive and, due to the low purchasing power of agricultural enterprises, the widespread use of organic fertilizers is hampered by the high costs of their transportation and application. In such conditions, the problem of increasing the yield and quality of crop products can be solved through the wider use of biologically based crop rotations

Crop rotations

Crop rotation– scientifically based rotation of crops (and fallow) across fields and over time. When introducing crop rotation, the land area is divided into approximately equal areas. Each crop in a certain sequence (according to the crop rotation scheme) is sown on each of them, passing through the entire field during the rotation (rotation). Compared to monoculture, crop rotation ensures the restoration and increase of soil fertility and rational use of land. Crop rotations are divided into: field (cultivation of grains, potatoes and industrial crops); feed (grasses, corn, etc.); special (vegetables, tobacco, rice, etc.).

Crop rotation promotes replenishment and better utilization nutrients soil and fertilizers, improving and maintaining favorable physical properties, protecting the soil from water and wind erosion, preventing the spread of weeds, diseases and pests of agricultural crops. As a result of crop rotation, soil fertility and crop yields significantly increase.

Structure of sown areas– the ratio of the area under crops of various agricultural crops. Usually expressed as the ratio of the area occupied by a particular agricultural crop to the total sown area of ​​all crops or to any crop (group of crops) as a percentage. The existing structure of sown areas on farms is clarified taking into account the need for crop products, economic efficiency, specialization, inter-farm cooperation, intensification of agricultural production, achievements of science, technology and best practices

The structure of sown areas depends on the specialization and concentration of production. In grain and livestock farms, field crop rotations are recommended, in which the grain group of crops occupies 55-60% of the arable land, and in pig and poultry farms - 65-70%. In farms specializing in the production of milk, beef and raising young cattle, grains should occupy 42-52%, technical - 10-15, feed - 30-40, steam - 5-10%

Crop rotation scheme– a list of crops and fallows in the order of their rotation in crop rotation

Of leading importance among agrotechnical practices are correct crop rotations, which ensure more complete satisfaction of the requirements of individual crops for environmental conditions. It is known that such conditions are created with agrotechnically sound crop rotation. Therefore, in the complex of agricultural practices for cultivating winter wheat, the leading place is occupied by the selection of predecessors. The agrotechnical importance of the latter on the fertile chernozem soils of the steppe regions is determined, first of all, by the residual moisture reserves, since the sowing of winter wheat coincides with the driest period of the year. The timeliness of the emergence of seedlings and the development of plants depends on the moisture reserves in the soil, which mainly determines the level of the future harvest.

Predecessor- an agricultural crop or fallow that occupied this field in the previous year. Other crops - flax, legumes, sunflower - greatly reduce the yield even when sown in a row for 2 years. This is mainly due to the spread of weeds, diseases and pests. The more specialized weeds, pests and pathogens a cultivated plant has and the weaker the measures to combat them, the greater the effect of crop rotation on the crop. The same crops that suffer less from weeds, pests and diseases tolerate re-seeding better.

With continuous sowing or improper rotation of crops, as a result of poor plant development, the spread of weeds, diseases and pests, the quality of flax fiber, cotton, potatoes, vegetables and fodder crops deteriorates, and the fat content in sunflower seeds decreases. This reduces the cost of products obtained per hectare, increases its cost and reduces farm income from farming

Correct crop rotation is important component farming systems. They are the basis on which systems for tillage, fertilization and protection of cultivated crops from weeds, pests and diseases are built, and soils from different types erosion

Correctly designed crop rotation has great value to improve farming standards, increase crop yields and profitability of farming. This role of crop rotation is determined, first of all, by the biological characteristics of crops. Different plants or groups of homogeneous crops require different conditions of the water or nutrient regime of the soil and at the same time themselves have different effects on the physical properties of the latter

The change of crops for all fields is shown in the form of a table called Rotational. It presents a plan for the placement of crops and clean fallow by field and year for the rotation period.

The alternation of groups of crops is called Crop rotation scheme. She reflects common features a number of similar crop rotations with different composition cultures, but with the same ratio and alternation of groups of cultures.

Two or more crops can be placed in one field if they belong to the same group. Fields in which two or more crops are separately located are called Prefabricated.

Changing crops in crop rotation can occur annually and periodically. In the latter case, the same crop is sown for 2-3 years in a row or more, and then it is replaced with another crop. Such crops are called Repeated if their duration is less than the rotation period

The economic basis of crop rotation is the production of the greatest amount of produce per hectare with the least amount of labor and money, rational use of land, labor and production methods - machines, tools and other materials. Performance economic tasks when introducing crop rotation, it is ensured by careful selection of crops and implementation of measures to obtain high yields

Science and practice have established that when winter wheat is sown, as well as other agricultural crops, for several years in one field, the yield and quality of grain decreases, pests such as ground beetles, Hessian flies, fall armyworms and others develop intensively. With proper alternation of crops in a crop rotation, this, as a rule, does not happen.

Taking into account the characteristics of various plants, their requirements for growing conditions, it is always possible to select such a rotation of crops and the structure of sown areas under which the development conditions for each of them will be the most favorable, which in turn will ensure high yields with minimal labor, material and monetary costs funds

The alternation of crops over time means the correct replacement of some plants by others in a given field, and the alternation of crops on a territory means that each crop passes through all fields of crop rotation. The period during which successive changes of all crops on the same field occurs is called Crop rotation. Crop rotation is also commonly referred to as the period during which each crop passes through all fields of the crop rotation. . The duration of rotation (number of years) is usually equal to the number of crop rotation fields. For example, in a ten-field crop rotation, the rotation duration is ten years

Introduction to crop rotation of crops that differ in terms of sowing and harvesting, nature of development, different ways caring for them contributes to a more uniform distribution and proper use of the machines, means and labor available on the farm throughout the year. The agrotechnical importance of crop rotations lies in the correct alternation of different biological requirements plants, in which the best conditions for growth and development are created for each crop

Permanent culture - Agricultural crop cultivated in one field long time. Permanent cropping should not be confused with concepts such as monoculture and repeated cropping.

Monoculture – the only crop cultivated on the farm. Unlike continuous operation, it can be interrupted by pure steam. Repeat culture- an agricultural crop cultivated in the same field for 2-3 years in a row. Based on the reaction to repeated sowings, three groups of crops are distinguished: those that greatly reduce the yield (fiber flax, sugar beets, clover, soybeans, peas, lupine, sunflower); medium-sensitive - capable of providing high yields with two or even three repeated sowings (rye, barley, wheat, oats, rice, potatoes, tobacco) with good fertilization, tillage and weed control; insensitive - capable of producing high and stable yields when repeated sowings over several years (cotton, corn, hemp).

Crop rotation link- part of a crop rotation consisting of two to three crops or pure fallow and one to three crops. For example, fallow – winter wheat, corn for silage – oats; perennial grasses – perennial grasses – lake. wheat - lake barley

One crop is usually sown in each field of crop rotation, which makes it possible to use sophisticated agricultural machinery and advanced agronomic practices. However, in some crop rotations, mainly with short rotation, sometimes it is impossible to place one crop in each field, then two crops are sown in one field, similar in their requirements for external conditions and agricultural technology (for example, winter rye and winter wheat, oats and spring barley ).

Fields where two or more crops are sown are called Prefabricated.

Prefabricated field– a crop rotation field in which several crops are cultivated separately. As a rule, crops with the same requirements for growing conditions and with the same cultivation technology are sown on such a field.

The negative impact of permanent crops on crop yields and the high efficiency of their correct rotation are well known. As a result of the intensification of agriculture, it becomes possible to expand the composition of crop predecessors using partially those that are considered unsuitable due to low agricultural technology (for example, oats for grains, grains for flax, etc.), as well as to use crops after good predecessors two and more than years in a row (winter and spring wheat, rice, cotton, hemp). All this, in turn, makes it possible to specialize crop rotations in intensive farming, while identifying the maximum agronomically and economically justified saturation of their main crops in order to obtain a high yield with good quality products is of particular importance

Agricultural science and practice have proven that with constant cropping, productivity decreases sharply. According to the Kharkov Experimental Station, the yield of winter wheat when sown for 15 years on the same field amounted to 9.1 c/ha, and in crop rotation over the same years - 18.5 c/ha, the oat yield averaged 16 years, respectively, was 10.7 and 14.8, potatoes - 95.6 and 167.4 c/ha. During continuous sowing, some row crops are severely damaged by pests and are affected by diseases. Thus, at the former Dnepropetrovsk experimental station, with a permanent sunflower crop, in the first year of sowing they received 11 centners of seeds per hectare, in the second - 11.1, in the third - 4.2, in the fourth - 2.2, and in the fifth year the crop died. The reason is severe damage to plants by broomrape. At the Sumy experimental station, on average over 20 years, the yield of sugar beet roots in crop rotation was 3.5 times higher compared to the yield on permanent crops. The negative impact of permanent crops can be mitigated to some extent by applying fertilizers

In arid areas, the most effective means of obtaining high and sustainable yields of grain crops is the inclusion of clean fallows in crop rotations - one of the effective means of combating drought. Therefore, the specialization of crop rotations for grain production in areas of insufficient and unstable moisture can be carried out with the correct ratio of grain crops and clean fallows

The construction of field crop rotations depends on the specialization of the farm and, above all, on the composition of the leading crops. Soil and climatic conditions, farm specialization, crop composition and their biological characteristics determine both the type of crop rotation and the order of crop rotation.

Crop rotations are classified by type and type. There are three main types: Field, Feed and Special. The name of the type is given according to the type of products grown. For example, the field type has 50% or more field crops in its structure, the forage type has 50% or more forage row crops, and the special type is characterized by the presence in the structure of crops that have a specific purpose (preventing soil loss on slope areas) or a special cultivation technology. The type of crop rotation reflects the presence of groups of crops in the crop rotation. For example, the crop rotation presented above is called grain-fallow-grass-row-crop.

Dmitry Nikolaevich Pryanishnikov identified 4 reasons for the need to rotate crops:

The reason is biological (reducing soil contamination with weeds, diseases and pests),

The reason is agrophysical order (optimal structure of the arable soil layer),

In each crop rotation, an alternation must be chosen that, along with the implementation of the developed sowing plan for the most important crops and increasing soil fertility, ensures maximum yields of all crops at best quality products

Crop rotation development plan– scheme of placement of cultivated crops in fields for the period of development of crop rotation.

Crop rotation transition table– scheme of placement of agricultural crops in the fields for each year of the transition period for the development of crop rotation.

Mastered called crop rotation, in which the accepted field boundaries are respected, and the placement of crops across fields and predecessors corresponds to the accepted pattern.

The focus of all activities aimed at ensuring high yields of cultivated crops in the arid conditions of our region should be the struggle for the accumulation, conservation and productive use of moisture by plants. In crop rotation, this is achieved by alternating crops that use soil moisture differently. Alfalfa, sunflower, and Sudanese grass consume the most water to form a unit of dry matter. Water consumption is one third less for winter wheat and the smallest for corn and millet. Different crops dry out the soil to different depths: perennial grasses, Sudan grass, sunflower and sugar beets by 1.5-2 m, while potatoes and melons consume moisture only from the upper layers of the soil. Thus, different crops have different effects on the water regime of the soil, which affects the yield of subsequent crops. This must be taken into account when selecting predecessors for all crops and, especially for winter crops, which are sown in more unfavorable moisture conditions than spring crops.

Proper alternation of crops in crop rotation also helps to improve the nutritional conditions of each of them. This is due to the different needs of different groups of plants for nutrients, as well as the ability to use nutrients from different layers of the soil. Cereals, for example, use relatively more phosphorus, root vegetables use potassium, and legumes use calcium.

In crop residues of various crops, according to prof. S.S. Rubin, the following amount of nitrogen is contained per hectare: after alfalfa 158 kg, sainfoin - 138, peas - 63, after winter wheat, oats, barley - 26-30 kg. Phosphorus and potassium remained: after alfalfa, 44 and 41, respectively, sainfoin - 43 and 48, wheat - 13 and 21, barley - 13 and 10, peas - 17 and 13 kg. Consequently, with proper rotation of crops, plants are better provided with soil nutrients than with continuous cropping.

As studies have shown, depending on the cultivated crops in crop rotation fields, water and food regimes and weeds changed, which significantly affected the productivity of arable land. Due to the drying out of the soil by perennial leguminous grasses in dry years in the fields occupied by alfalfa and alfalfa-rump mixture, by spring the reserves of productive moisture in the meter layer of soil were 20-30 mm less than in the plowed land after cereal grains and row crops. In moderate and dry years, on average, for one field of crop rotation with one field of alfalfa, the reserves of productive moisture in a meter layer of soil decreased by 5-7 mm, and in a crop rotation with two fields of alfalfa - by 13 mm. By harvest, the average moisture deficit per field of crop rotation with one field of alfalfa was 10-13 mm, and with two fields of alfalfa or one field of alfalfa-rump mixture - 17-18 mm. In wetter years, such a significant lack of moisture was not observed.

When growing annual crops, the soil is worked much more often than when growing, say, perennial grasses. As a result, it is sprayed, its structure is gradually destroyed, physical properties, water and air permeability, thermal properties, etc. deteriorate. Therefore, crop rotations must necessarily include agrotechnical measures aimed at restoring the soil structure. Along with the correct system of soil cultivation and fertilization, perennial grasses restore the structure well. Therefore, introducing them into crop rotation has important to increase soil fertility.

The role of crop rotation in the fight against weeds is extremely important. Different crops tolerate weeds differently. Those that grow quickly in the initial stage (winter wheat, rye and others) outpace weeds and suppress them, while plants that grow slowly in the first period (millet, Sudanese grass) suffer more from weeds. Therefore, alternating them, as well as continuous sowing crops with row crops, winter crops with spring crops, etc., helps clear the fields of weeds. The presence of a fallow field in the crop rotation, in which special measures are taken to combat weeds, further enhances the role of crop rotation in the fight against weeds in fields

Crop rotations are of great importance in the fight against pests and diseases of agricultural crops. Most pests and diseases tend to become adapted to one or more crops. With continuous crops, the risk of damage to plants by them increases and, conversely, almost disappears when changing crops.

Proper alternation of crops in crop rotation is also associated with soil health: toxic substances accumulating in it are eliminated biological origin, fungal diseases and the so-called phenomenon of soil fatigue.

Crop rotations, therefore, are a proven means of properly organizing land territory, rationally using means of production, increasing soil fertility, and controlling weeds, pests and diseases of agricultural crops.

The structure of sown areas is developed directly in agricultural formations, based on long-term plans farms, taking into account the fulfillment of state tasks for the sale of agricultural products and the full provision of the farm with the necessary products and feed for livestock farming.

When developing a rational structure of sown areas, it is necessary to take into account the productivity and economic efficiency of each crop and its impact on soil fertility. It is known that different plants, due to their biological characteristics, have unequal productivity. Some of them can provide more feed units and digestible protein, others less. But the same crop, for example corn or sugar beets, in one zone can give a very high yield per unit area and be economically profitable, but in another zone it can give a low yield and be unprofitable. It is also necessary to take into account the quality of crop products.

An important economic and organizational requirement for crop rotation is the correct placement of crops on the territory, which will allow the most rational use of the land. The composition and alternation of cultivated plants in crop rotation determine the timing and methods of tillage, sowing, caring for crops, harvesting and other work. For example, spring wheat and other spring cereals in most regions of our country are sown in a short period of early spring, winter wheat and rye in the fall, and corn, castor beans and others in the spring, after sowing early grains. For each crop, soil cultivation and other work are carried out at different times. Different cultivated plants have different growing seasons, so they ripen at different times. The correct combination of crops in crop rotation according to the timing of their sowing and harvesting makes it possible to make the most rational use of labor resources, agricultural machinery, and increase soil fertility and labor productivity.

The number and size of crop rotation fields is of great importance for the better use of tractors, agricultural machines and other means of production. Larger fields create more favorable conditions for better use of means of production.

With monoculture, difficulties arise in carrying out field work at optimal times, in uniform and more complete use of agricultural machinery and labor.

To evaluate crop rotations based on their economic efficiency, it is necessary to take into account the following most important indicators:

A) crop yields in crop rotation and gross harvest of main and by-products;

B) the yield of feed units and protein per unit of crop rotation area;

C) labor costs in man-hours and in hryvnias (wages, fuel costs, depreciation and repair charges) per unit of crop rotation area;

D) gross output in hryvnias per unit of crop rotation area and per 1 hryvnia of costs;

D) net income in hryvnias per hectare of crop rotation area and per 1 UAH. costs.

It is necessary to evaluate crop rotations not by one, but by several important indicators.

Based on the gross harvest of agricultural products, it will be possible to judge the possible quantity of products for sale on the market and satisfaction of on-farm needs.

It is important to obtain not only a large amount of products from each hectare, but that these products cost the farm as little as possible

The volume of gross output, expressed in hryvnias per hectare of crop rotation area, will indicate the productivity of its use and will partially reflect the degree of specialization of agriculture. Net income per hectare of crop rotation area and per 1 hryvnia of annual costs will characterize the overall economic efficiency of crop rotation, and the ratio of net income to costs will characterize the profitability of crop rotation.

These are the main indicators by which one can judge the economic efficiency of crop rotations.

To obtain high yields of all crops in a crop rotation, it is necessary, based on the accepted structure of sown areas, to establish alternation of plants in such a sequence that each of them corresponds to the best predecessor. At the same time, it is important that more valuable crops and those that are more demanding of soil fertility, field cleanliness and other conditions follow the best predecessor and that they, in turn, are a good predecessor for subsequent crops

Principles of constructing crop rotations and their links.

When placing crops, it is necessary to take into account their requirements for predecessors. Thus, for winter crops, a certain period is required from harvesting the predecessor to sowing to prepare the soil; cleanliness of the field from weeds, especially perennial, wintering, biennial; cleanliness of soil and plant residues from pathogens and pests; the presence of the necessary amount of productive moisture to obtain full germination and good plant development in the fall; the presence of a sufficient amount of nutrients in the arable layer. In conditions of insufficient and unstable moisture, the highest stable grain yield of winter wheat is provided by clean steam. Good harvests are obtained after busy fallows (sainfoin and sweet clover for one cut, winter and spring mixtures for fodder). These predecessors more often than others ensure the accumulation of at least 10 mm of productive moisture in the 0-10 cm soil layer by the time of sowing winter wheat. After harvesting corn for silage, the probability of creating sufficient moisture reserves in the seed layer is much less (Nikolaev E.V., Gordienko V.P., 1994).

By the spring of next year, reserves of productive moisture in a meter-long soil layer are in most cases restored by autumn and winter-early spring precipitation, but in deeper layers of soil, moisture deficiency often remains. Therefore, when constructing crop rotations, crops should be placed so that after crops with a deep-penetrating root system, moisture reserves are restored at great depths.

The features of constructing crop rotations on irrigated lands include: saturation with highly productive crops that are most responsive to additional irrigation (alfalfa, corn, root crops, vegetables); to maintain high soil fertility, perennial grasses are introduced into all types of crop rotations (up to 25-30%); In the presence of crops with a relatively short growing season, crop rotations are compacted with intercrops, repeated crops are more widely used) to restore the fertility of irrigated lands, especially when cultivating rice, the so-called agro-reclamation field is introduced into rice crop rotations.

In irrigated crop rotations, arable land can be used in two ways: by growing four to five crops with a long growing season (corn, sorghum, soybeans, vegetables, alfalfa) or by sowing cereal grains, vegetables, melons and potatoes, forage crops with a short period of active growing season, followed by cultivation after them, stubble and mowing crops (buckwheat, millet, potatoes and summer vegetables, fodder). In all cases, the construction of crop rotations should be such that the growing season, thermal resources of the zone, irrigation water, reclamation and agricultural equipment are used as fully and rationally as possible.

During irrigation, the role of precursors changes significantly. Many of them, which strongly dry out the soil in dry conditions, when irrigated become good predecessors for subsequent crops, and only the deterioration of the phytosanitary condition and increased weediness of the fields can cause a decrease in their agrotechnical assessment.

In the very first years of developing crop rotations, it is necessary to strive to have one crop in each field or several similar in their cultivation methods in order to quickly move on to placing them according to the established rotation in crop rotation.

When drawing up a transition plan, follow approximately the following sequence:

1) establish a plan or sequence for the development of new land masses involved in crop rotation, and land with greater economic value is designated for plowing first;

2) specify and record crops that were sown last year, but will produce a harvest next year - winter and perennial grasses;

3) the most valuable crops of the introduced crop rotation are placed after the best predecessors:

4) less demanding crops, taking into account their commercial value, are placed after the remaining predecessors;

5) then fields of clean or occupied fallow are placed, under which the most clogged fields with the worst predecessors are allocated;

6) in addition, in crop rotations with grass sowing, a place for reseeding perennial grasses is determined.

In the southern regions, perennial grasses are most often sown under spring grain crops - barley, oats, and sometimes millet. In the non-chernozem zone, on less heavy soils, perennial grasses are sown mainly under winter crops - winter rye, winter wheat, and on heavier soils - under barley, oats and spring wheat.

The plan for the transition to new crop rotations must be drawn up so that each crop in the first year of mastering the crop rotation is placed after good predecessors

Based on the above, we can conclude that crop rotation is the basis for stable, high-quality yields of agricultural crops.

Research conducted in a stationary experiment to study crop rotations

(VNIIZH), show that on average over the years of research (1968–1978) from

the studied precursors leave the most organic residues

perennial grasses, then corn and a pea-oat mixture. From grains - wheat,

sown in pure fallow. The accumulation of plant residues, in general across crop rotations, varied annually and over many years depending on the structure of sown areas and crop rotation. Five-field grain steam

crop rotation with a breeding field of perennial grasses turned out to be the most acceptable in terms of this indicator in local conditions, since here the supply of plant residues on average per year was 12%, and in a 4-field grain-row crop -

only 6.3%. The qualitative composition of plant residues is also of great importance. The organic residues of perennial grasses contain more nitrogen and phosphorus than those left behind by wheat and barley, while at the same time, the pea-oat mixture is not inferior to perennial grasses in enriching the soil with nitrogen, phosphorus and potassium.

Through scientifically based crop rotation it is possible to a certain extent

regulate the accumulation of organic residues in the soil. Research data show that in terms of soil enrichment with nitrogen, the best place is occupied by 6-field

grain-fallow crop rotation with annual legume-cereal grasses and 5-field

grain-fallow crop rotation with a field of perennial grasses. These same crop rotations turned out to be the best in terms of phosphorus supply. Continuous cultivation of wheat or grains leads to a decrease in the accumulation of organic residues.

A holistic picture of the change in the balance of organic matter in the soils of Northern Kazakhstan can be formed using data on its arrival and removal from the harvest. The accumulation of humus in the soil is a long-term process. Of all organic residues entering the soil, only 22-30% can be converted into humic substances. According to A.N. Shenyavsky (1973), up to 10% of humus can be formed from straw, up to 18% from the roots of plant collars, and up to 20-40% from manure.

The amount of organic residues as a percentage of the original amount used for the formation of humic substances is called the isohumus coefficient, which is used to calculate the balance of organic matter using the equation: B = Aa – 20UN

where B is humus balance, kg/ha;

A – amount of root and crop residues, c/ha;

a – isohumus coefficient, %;

Y is the yield of the main product, c/ha;

N – nitrogen removal from 1 centner of crop, kg;

20 – conversion factor for humus loss from the soil.

According to the results of research by V.I. Rylushkina (1977), carried out on ordinary chernozems of the Tselinograd region, it was established that total reserves humus in the A+B horizon amounted to 249t/ha. When using these soils for sowing wheat with a yield of 14.5 c/ha, the unrecovered loss of humus per hectare reaches 157.6 kg or 0.06% is lost annually, and on southern carbonate chernozems with a wheat yield of 15.1 c/ha, up to 206 kg/ha are irretrievably lost. ha of humus or 0.13%.

A completely different situation arises on the same soils when sowing perennial grasses. Due to the abundant enrichment of the soil with root residues, a less pronounced process of mineralization of organic matter against such a background results in a positive balance of humus. Thus, with an average yield of wheat grain hay in the second year of life of 12 t/ha, the increase in humus to the existing 128 t/ha in the arable horizon amounted to 285 kg/ha.

This suggests that the continuous cultivation of wheat in the northern regions of Kazakhstan is associated with a negative humus balance, therefore it is possible to significantly influence the course of changes in soil organic matter by applying organic and mineral fertilizers, leaving straw on the fields, and introducing perennial grasses into the crop rotation.

Adding or leaving straw on the fields is the simplest and most convenient way, which significantly affects the elimination of the deficit-free humus balance. For example, in generalized studies on Northern Kazakhstan (A.A. Zaitseva, 1974; V.I. Kiryushin, I.N. Lebedeva, 1972) it was found that only leaving stubble on the soil surface contributed to an increase in humus content over a seven-year period by 0. 26%.

Thus, a rational combination of such agricultural practices as applying mineral fertilizers in recommended doses, leaving stubble, spreading straw, applying organic fertilizers, using recommended crop rotations, soil cultivation systems, etc. can significantly affect the change in the content of organic matter, reducing its losses to deficit-free balance.

The soils of Northern Kazakhstan are poor in available forms of phosphorus. The only way to improve the phosphorus regime of the soil is to apply phosphorus fertilizers in recommended doses.

Precursors have a different effect on the content of nitrate nitrogen in the soil. The best precursor for the accumulation of available nitrogen is steam. The aftereffect of steam in providing plants with nitrate nitrogen extends to the third crop inclusive. For wheat removed from fallow (4-5 crops), nitrogen fertilizers should be applied.

It is known that field crops, due to biological characteristics, consume unequal amounts of moisture. Therefore, alternating them with each other, and in case of insufficient moisture with steam, is a decisive factor in the rational use of soil moisture.

An analysis of the moisture supply of crops shows that in the arid zone of Northern Kazakhstan it is advisable to sow wheat two years after fallow, having a third crop of oats or barley and close the crop rotation with wheat sown after oats, and if necessary, the rotation of these crop rotations can be extended to 6-7 years, sowing in the sixth a grain fodder field, and in the seventh - a breeding field of perennial grasses.

Crop rotations and weed infestation. Alternation of crops in crop rotation in combination with their zonal agricultural technology is an effective means of reducing crop infestation. Steam is the leader in the fight against weeds, but to increase the debris-cleaning role of steam precursors, especially occupied and combined steam, it is necessary to use herbicides on the steam, which, in combination with mechanical treatments, effectively suppress and destroy weeds.

Good results can be achieved in weed control by using herbicides in crop rotation on the second, third and subsequent crops of the crop rotation.

Among the measures to improve the quality of wheat grain, an important place is occupied by sowing it in fallow, the second and third crop after fallow, and in pea-oat mixture.

In pure fallow, grain yields and quality are always higher than in other fields.

Control questions

1.What is the role of crop rotation in agrolandscape farming systems ?

2.What are the reasons for crop rotation?

3. The role of fruit replacement in the development of scientific and practical agriculture.

4.What types and types of crop rotations are used in agriculture?

5.What is the role of perennial grasses in crop rotations in different zones?

6.The main precursors of wheat in steppe zone.

7. Characterize the soil-protective ability of the main field crops.

8.What is strip placement of crops?

9.Give examples of special crop rotations.

10.What is the purpose of transition and rotation tables?

11.Environmental requirements for crop rotation.

SECTION 4. Soil cultivation.

Lecture 10. Scientific foundations of soil cultivation.

1. Tillage tasks.

2. Technological operations performed during soil cultivation.

3. Physical properties of the soil.

Tillage tasks.

Improving soil fertility efficiency and creating favorable conditions for plant growth are inextricably linked with soil cultivation . Treatment– this is a mechanical effect on the soil by the working parts of soil-cultivating machines and implements to create optimal soil conditions for grown plants. Tillage is the main agrotechnical means of regulating soil regimes, the intensity of biological processes, and maintaining good phytosanitary condition of soil and crops.

With the help of mechanical tillage the following goals are achieved:

Giving the soil a fine-clumping structural state and an optimal soil composition for plants (density, porosity, etc.), which would create water, air, nutrient and thermal conditions favorable for the growth of plants and microflora;

Maintaining good phytosanitary condition of soil and crops;

Prevention of erosion processes, excessive soil compaction,

reduction of unproductive losses of water, humus, and nutrients from the soil

in order to preserve potential fertility and protect the soil from erosion.

Tillage is necessary to deepen and increase power

arable layer, for incorporation of organic and mineral fertilizers, as well as

ameliorants for the purpose of soil reproduction and cultivation.

In steppe arid conditions, on sloping lands, deep loosening of the soil contributes to the accumulation of moisture and precipitation in the root layer. In areas of excessive waterlogging, soil cultivation can remove excess water from the field, resulting in improved soil air conditions.

Agrophysical foundations of soil cultivation

Favorable soil conditions for the growth and development of plants develop with optimal parameters of the agrophysical properties of the soil and indicators of its fertility. The most important conditions include the density and structure of the soil, the thickness of the arable layer, the structural composition, etc.

The modern theory of cultivation is based on a reasonable coordination of the agrophysical properties of the soil and the requirements of cultivated plants for them. Therefore, the most important agrophysical basis for processing is the crop requirements for the density and structure of the arable layer, the structure and degree of crumbling of the soil, the thickness of the arable layer, hardness and other properties on which plant growth and productivity depend.

A quantitative characteristic of the structure of the soil is the value of its density. There are equilibrium and optimal soil densities. Equilibrium density is the steady-state density of untreated (1-2 years) soil in natural state. The density of the soil, at which favorable conditions are created for plant growth and the activity of soil microorganisms, is called optimal.

The study of the response of crops to the physical state of soils of various genesis made it possible to identify intervals of optimal values ​​of soil density for grain and row crops. The optimal soil density of loamy chernozems for grain crops is 1.1–1.3 g/cm3, for row crops – 1.0–1.2.

Soil density depends on the particle size distribution, humus content, water-resistant aggregates, soil moisture and other conditions.

Agrochemical and biological basis of soil cultivation.

Methods of basic tillage have a significant impact on the distribution of organic matter and applied fertilizers in the soil, the availability of mineral nutrition elements to plants, the processes of humification of plant residues and the synthesis of biological nitrogen.

A significant role in increasing soil fertility belongs to biological processes, the activity of which is determined by the conditions created by soil cultivation. Therefore, soil cultivation is the most important means of regulating life activity. soil microflora, its abundance and species composition. Loosening the soil improves aeration, its moisture and increases the number of bacteria, molds, actinomycetes and other microorganisms that decompose carbon-containing plant matter.

Increasing the vital activity of aerobic microorganisms accelerates the decomposition of humus and the release of mineral nutrition elements.

With a decrease in the intensity and depth of loosening, the use of shallow or surface tillage, the activity of soil microflora decreases and humic substances, which serve as a potential source of plant nutrients and a means of improving the structure and physical properties of the soil, do not decompose.

The method and depth of treatment affect the infectious potential of the soil and its contamination. An increase in crop infestation during non-moldboard cultivation and minimization techniques, an increase in crop infestation by diseases and pests create the prerequisites for alternating different methods and depths of soil cultivation in crop rotations. By destroying weeds by processing, using deep loosening of the arable layer, flat-cutting, chisel processing in dry conditions, we improve the moisture supply of plants and accelerate their growth. As a result, the susceptibility of crops to pests and diseases is reduced.

With a variety of methods and tools for tillage, their use comes down to solving the following problems:

Creation of a favorable fine-clump structure of the arable soil layer. This is the main task and it is solved by deep tillage techniques.

Destruction or suppression of weeds;

Creating conditions for the accumulation and preservation of moisture in dry areas and eliminating excess soil moisture in areas of excess moisture;

Improving the nutritional regime of the soil by redistributing nutrients in the arable layer and influencing microbiological processes;

Creation of favorable conditions for planting seeds of cultivated plants into the soil, their friendly germination, growth and development;

Destruction or suppression of certain pests and diseases of agricultural crops;

Incorporation of organic and mineral fertilizers, chemical ameliorants, herbicides and pesticides into the soil;

Deprivation of the vitality of a turf deposit or layer of perennial grasses;

Maintaining conditions under which the surface layer of soil remains resistant to erosion and deflation.

In general, the treatment achieves optimization of the water, air, microbiological and nutritional regimes of the soil. Creating an optimal structure (formulation) of the arable soil layer and the desire to create a favorable water regime also ensures a favorable air regime (aeration).

S.A. Zamyatin, Ph.D. V.M. Izmestiev, Ph.D. ON THE. Krivoshchekova

Mari Research Institute of Agriculture

Increasing soil fertility and biological intensification of agriculture is relevant all over the world. Evidence of this is the large-scale degradation of soil cover not only in agricultural landscapes, but also in the ecosystem as a whole.

Based on the available generally accepted experimental data, it can be stated that the balance between biogenic (biological) and technogenic (anthropogenic) factors is disturbed not in favor of the former. Therefore, today it is legitimate to talk about the tasks and ways of increasing the role of biological factors and their intensification in modern and global agriculture.

Long-term exploitation of soddy-podzolic soils has led to a deterioration in their physical and physico-chemical properties, as a result of which a decrease in the level of sustainability of their productivity has been observed everywhere. The degradation of soddy-podzolic soils is primarily due to a decrease in their reserves of organic matter.

Soddy-podzolic soils make up 86% of the arable land of the Republic of Mari El. They do not have high natural fertility. The highest effective fertility is in the top ten centimeter layer of soil. Mechanical tillage entails profound changes in the biological properties of the soil, which are restored again after two and a half to three months.

Research in field crop rotations with varying degrees of saturation with grain crops was carried out on the experimental field of the Mari Research Institute of Agriculture and was introduced into one field with rotation of crops over time. Two stationary experiments were carried out in 1996 and 1998. on soddy-podzolic, medium loamy, well-cultivated soil with a high content of mobile forms of phosphorus and exchangeable potassium.

Crop rotation schemes: 1 crop rotation (oats + clover, clover 1 g.p., spring wheat, vetch/oats (grain), winter crops, barley). 2 crop rotation (vetch/oats (fallow), winter crops, barley, potatoes, vetch/oats (grain), spring wheat). 3 crop rotation (vetch/oats (grain), spring wheat, potatoes (manure 80 t/ha), barley + clover, clover 1 g.p., winter crops). 4 crop rotation (barley + clover, clover 1 g.p., clover 2 g.p., winter crops, potatoes, oats).

In the second rotation of crop rotations, in addition to the generally accepted agricultural technology of field crops, the influence of non-traditional sources of organic fertilizers (chopped straw, root residues of clover, rejected at a high cut) on soil fertility is being studied.

Thus, over two rotations of field crop rotations, the humus content in the soil increased in all crop rotations studied by 0.12-0.46%, especially against the background of the application of mineral fertilizers and in the 3rd crop rotation when using organic fertilizers.

According to the acidity of the soil solution for two rotations of all studied crop rotations, a weak tendency towards soil acidification is noted. Greater acidification of the soil is observed in variants when using mineral fertilizers.

During the observation period, the content of mobile forms of phosphorus in the soil remained at the initial level, although a slight increase in the value of this indicator was observed when mineral fertilizers were applied.

We conducted research on the group composition of humus in 2009. The content of total carbon in the soil with conventional technology was 1.13%, with plowing of straw and clover green manure - 1.23%, with the application of mineral fertilizers - 1.15%, without application such - 1.20%.

It should be noted that the carbon content of humic acids for soddy-podzolic soil in the experiment is consistent with the data of Tyurin and Kononova (12-20%) given by A.E. Vozbutskaya (1968). Fulvic acids predominated in the humus composition, which is typical for soddy-podzolic soils.

An important qualitative characteristic of soil humus is the ratio of the content of humic acids to fulvic acids. On average, for background fertilizers, its values ​​were: with conventional technology and against a background with mineral fertilizer - 0.68, with plowing straw and against a background without fertilizers - 0.72.

Thus, based on the conducted research, we can conclude that the humus content in the soil tended to increase; according to the soil acidity content, there is a weak tendency towards acidification of the soil. The content of mobile forms of phosphorus in the soil remained at the same level, and the content of exchangeable potassium showed a tendency towards its decrease. The composition of humus is dominated by fulvic acids, which is typical for soddy-podzolic soils.

Literature

1. Kuznetsova E. Increasing soil fertility and productivity of agrocenoses in the Russian Federation / E. Kuznetsova, E. Zakabunina, D. Popov // Chief Agronomist. - 2010 - No. 4. - P. 9-10. 2. Kuznetsova E. Influence of the ecological environment, forest and green manure crops on increasing soil fertility and productivity of agrocenoses / E. Kuznetsova, E. Zakabunina, S. Sergeev, D. Popov, M. Burdyugov // Chief Agronomist. - 2010 - No. 6. - P. 8-10. 3. Khristoforov L.V. Ways to increase the fertility of soddy-podzolic soils of the Republic of Mari El. /L.V. Khristoforov, G.V. Pidalin // Current problems of agriculture in modern stage development of agriculture // Collection of materials of the international scientific-practical conference dedicated to the 50th anniversary of the Department of General Agriculture. - Penza: RIO PGSHA, 2004. - pp. 42-43.

Crop rotations are commonly referred to as the scientifically substantiated alternation of fallow areas and agricultural crops in time and territory, sometimes only in time.

When developing crop rotations and placing crops on a plot of land, they use and take into account the characteristics of each crop, as well as its production value. First of all, it is important to pay attention to such basic biological features as the use of nutrients from different layers of soil and moisture throughout the growing season, as well as the amount of plant and crop residues, the degree of damage by diseases and pests, loss of humus under different crops, and soil toxicity.

When improving crop rotation, it is necessary to take care of increasing the content of organic matter (humus) in the soil to increase its fertility; this can be achieved by introducing the cultivation of perennial grasses into crop rotations.

Crop rotation table for grains and other agricultural crops

Culture	Predecessors
Winter grains (wheat, rye, barley)	Clean fallows, perennial grasses, busy fallows, legumes, corn for green fodder and silage, winter grains.
Spring wheat	Clean fallows, row crops, perennial grasses, busy fallows, leguminous crops, winter grains.
Spring barley	Row crops, legumes, winter grains, spring wheat, industrial non-row crops
	Row crops, legumes, winter grains in pairs or perennial grasses
Peas, vetch, lentils, lupine, soybeans and other legumes	Row crops (except legumes), winter and spring grain crops
Potato	Winter grains, legumes, perennial grasses, row crops, spring grains
Sugar beet	Winter grains, legumes, potatoes, spring wheat
Corn	Winter grains, potatoes, legumes, spring wheat, oats, barley
Sunflower	Winter grains, legumes, corn, coriander
Fiber flax	Perennial grasses, legumes, potatoes, corn for silage, winter crops for perennial grasses
	Perennial grasses, legumes, row crops

In addition to agrotechnical significance, the rotation of crops in the fields has organizational and economic significance. In practice, it has been proven that the introduction of various types of crop rotation helps to reduce stress on the farm; work is distributed more evenly throughout almost the entire year, and in the presence of livestock farming, generally throughout the year.

Crop rotations are developed individually for each farm, taking into account soil, climatic and economic conditions. They must provide the farm with an increase in soil fertility, the fulfillment of planned gross indicators, an increase in crop yields, the creation optimal conditions for organizing labor and using agricultural machinery, protecting fertile soil from erosion.

Types and types

There are several types and types of crop rotations, depending on the crop and the direction of production of the farm, but most farmers know about three types:

• Special- this is when crop rotation is focused on growing one or two crops that are cultivated on 40-60% of the arable land area (vegetables, melons, rice, etc.).
• Field- these are crop rotations where more than 50% of arable land is sown with grain and industrial crops. Forage crops here occupy from 10 to 40% of the arable land. They (feed) are at the same time predecessors for grain, industrial and vegetable crops.
• Feed- oriented for implementation in livestock farms. They are primarily intended for the production of green mass (grass), silage, root crops, silage and hay. Depending on the direction of cultivation of a particular ball crop, fodder crop rotations are divided into near-farm crop rotations (annual cereal crops, perennial grasses, root crops) and grassland (natural grasses are used, with overseeding of meadow grasses and annual cereal crops).

All types of crop rotations are divided into the following types:

• Grain-steam- in them, grains are sown on a larger area of ​​arable land, the rest is fallow (the area where crops are not grown).
• Grain and fallow crops- half the area or even more is fallow areas, the rest is row crops (beets, potatoes, etc.).
• Grain crops- they cultivate the same crops as in grain-fallow crops, only there is no fallow here.
• Grain-grass- the name itself says that in this type of crop rotation, most of the field area is allocated for crops of grain and some industrial crops, and the other part is occupied by perennial grasses.
• Grain-grass or fruit-replacement crop rotations- consist of grains, row crops, vegetables, perennial legumes and annual crops. The essence of fruit rotation comes down to the fact that every year the grain crop is replaced with a non-grain broad-leaved crop belonging to row crops or legumes. Such crop rotations are typical for beet-growing areas and where there is irrigation.
• Row crops- here, for row crops (corn, sugar beets, sunflowers and others), more than half of the field area is allocated. They include one or two fields of annual non-grass crops and are often used in on-farm forage crop rotations.
• Grass-bearing- in such crop rotations, a significant part (2/3) is sown with perennial grasses. Such crop rotations have found wide application on irrigated lands and in areas with excess moisture.
• Green manure- crop rotations aimed at growing one or two crops that are plowed for green fertilizers. Such crop rotations are used, mainly on light sandy soils (to saturate the soil with organic matter).

When soil is used for agriculture without fertilizer, it is gradually depleted and yields fall. This was noted in ancient times. Thus, Tacitus (1st century AD) wrote that the Germans change fields every year to sow plants.

In the south of Russia, in the steppe zone, a “fallow” system arose, in which more or less carefully cultivated virgin soil was sown with wheat, rye or oats for several years in a row, and after depletion, it was turned into fallow land (fallow land).

In Russia there was also a “fire” or “slash” farming system, which was used in the more northern zone. Trees and shrubs felled in the summer were “pulled” in the fall. Useful wood was taken out and the remaining wood was burned in the field. After use, the soil was left to “rest” for a number of years to restore fertility.

As population increases, the need for land area increased, and a system of “accelerated” soil rest arose in the form of the so-called three-shelf system, in which fallow (fallow), winter and spring crops alternated. This system was widely used until the beginning of the 20th century, when more complex crop rotations that preserved soil fertility gradually began to be introduced.

After the Great October Revolution socialist revolution The three-field system was replaced by grass-field and fruit replacement systems, which included sowing grass mixtures. During grass fields, grasses occupy up to 30-40% of the soil, and during fruiting - 20-25%. Each soil-climatic zone requires its own crop rotation.

The feasibility and even the necessity of introducing crop rotation arose when it was established adverse effect on soil fertility of long-term cultivation of the same crop in a field. A clear confirmation of this is the experience laid down by D.N. Pryanishnikov at TSCA on soddy-podzolic soils. The average crop yields obtained 50 years after the start of the experiment are shown in Table 17.

It is quite obvious that in crop rotation with clover the yields were significantly better than with permanent crops.

Similar data were obtained in a long-term experiment conducted on the black soil of the Mironovsky Institute of Wheat Breeding and Seed Production, where the experiment also lasted about 50 years. The yield of winter wheat during continuous cultivation without fertilizers was 20 c/ha, with the application of manure - 26.9 c/ha; in crop rotation - 35.5 and 54.4 c/ha, respectively.

The peasants fully appreciated the importance of alternating crops and it was not for nothing that they coined the saying: “To sow bread after grain, neither grind nor winnow.” However, some plants, such as corn and potatoes, are less susceptible to monoculture. Sometimes the predecessor improves the growth of the subsequent crop, which largely applies to legumes. The noted phenomenon, which in the case of oppression received the name “soil fatigue,” has been known for a long time. Back in 1796, N. M. Maksimovich-Ambodik wrote about it in his work “The Initial Botanists of the Foundation.”

How can a predecessor influence a subsequent culture, and what role does the microbiological factor play? Here we encounter a complex of phenomena. Some plants one-sidedly deplete the soil of certain nutrients. Under row crops, the soil is not only depleted, but its structure also deteriorates significantly. It is not recommended to cultivate agricultural plants one after another that have common pests, including microbiological ones.

The fact that soil fatigue can be caused by microorganisms is evidenced by the experience of N. A. Krasilnikov. Clover seeds were added to flasks with an agarized mineral nutrient medium. A small amount of “tired” soil was placed in some of the flasks. This caused the rapid death of the seedlings under the influence of microorganisms. The same soil, but sterilized, did not produce an adverse effect (Table 18).

However, there are other reasons that determine the influence of one plant on another, in particular of a chemical nature. This is the so-called allelopathic effect of plants. The term “allelopathy” was proposed by the German scientist G. Molisch to define the chemical effect of one plant on another. Many angiosperms are capable of producing certain toxic substances, including alkaloids. These compounds not only accumulate in plant tissues, but are also partially released into the soil.

This property is inherent in most cultivated plants. Thus, the root system of oats secretes scopoletin (a substance close to coumarin), lei - a number of aromatic compounds (ferulic, hydroxybenzoic acids, etc.), alfalfa - alkaloids, sugar beets - cyclic compounds (hydroxybenzoic, coumaric, ferulic, vanillic acids ) etc.

N. G. Kholodny, and then other researchers, established that many volatile plant compounds have an allelopathic effect. Among them are aldehydes, terpenes, ethylene, essential oils, etc.

Some substances that have a toxic effect on plants have been found in crop residues. In the straw of cereal plants, such substances include cyclic compounds: coumaric, hydroxybeisoic, ferulic, syringic acids, etc. Quinones have a strong allelopathic effect.

G. Grümmer proposed to call substances of plant organisms that have a chemical effect on other plants

"Kolins". In high concentrations they inhibit plant growth, and in low concentrations they stimulate.

Obviously, scientifically based crop rotation should be based on the allelopathic factor. It is known that after sugar beets, corn grows poorly, after oats, the germination of wheat seeds drops sharply, and when barley is sowed again, its yield sharply decreases. Acute soil fatigue is observed in monocultures of sugar beets, flax, peas, clover, alfalfa, and many fruit plants. However, corn, potatoes, rye, tobacco, grapes and some vegetables do not experience suppression in monoculture.

As a rule, legumes (especially perennials) have a beneficial effect on subsequent crops due to the fact that they, in symbiosis with nodule bacteria, enrich the soil with nitrogen. This leads to a significant increase in the yield of subsequent crops. According to D.N. Pryanishnikov, after crop rotation with clover was introduced in Europe, the average yield of grain crops rose from 7 to 16 quintals per hectare. In TSKhA, on soddy-podzolic soil, a six-field crop rotation with annual clover allowed for a rye harvest of 13.4 c/ha for 50 years (without the application of mineral fertilizers). In the same crop rotation, but without clover, only 6.7 c/ha was obtained.

On black soil Voronezh region in a four-field crop rotation without legumes and fertilizer, winter wheat yielded about 20 c/ha. When using annual clover in crop rotation, the yield increased to 25, and biennial clover - to 28 c/ha. Such yields remained stable for 17 years.

The high efficiency of alfalfa and rapeseed as cotton precursors is well known. This is largely due to the fact that the root system of these plants releases compounds (alkaloids and other substances) into the soil that inhibit the pathogens of cotton wilt. In addition, alfalfa enriches the soil with nitrogen.

The great effectiveness of legumes as predecessors of agricultural plants has also been shown by foreign experimental institutions. Table 19 shows data from the Rothamsted

Experimental station (England), clearly demonstrating this.

Based on experimental data, D.N. Pryanishnikov concluded that greater value as precursors of leguminous grasses of pure sowing in comparison with their mixtures with cereal grasses.

In conclusion, we note that in the middle of the 19th century, when, after the work of the German scientist J. Liebig, mineral fertilizers began to be widely used, the importance of crop rotation was often not taken into account. At first, yields increased sharply, but soon began to decline even with increasing fertilizer rates. The point of view of Moscow University professor Ya. A. Linovsky was justified, who pointed out that when solving issues of soil fertility, one should take into account not only the mineral nutrition of plants, but also other factors, including crop rotation.