How to do a soil analysis. Soil analysis at home


Greetings, friends!

When creating a new personal plot or reconstruction of a very old important stage is to study the soil conditions of the existing territory. It is advisable to carry out this work before the design of the garden begins, in order to be able to improve the necessary soil characteristics.

This largely determines how the plants will feel in the new garden. It is no secret that in nutrient-rich, moderately moist, cultivated garden soil, yields are significantly higher. In addition, some adjustment of soil conditions allows you to expand the range cultivated plants on the site. So let's talk about how to conduct a soil test on a newly selected or existing site.

A complete and very detailed study of soils can only be done in a laboratory. But every summer resident is able to conduct a simple independent analysis and draw conclusions sufficient for further work. As part of such a field study, the following is established:

1. Mechanical composition.

2. Degree of aeration.

3. Acidity.

4. Hydrological features.

5. Fertility.

All these qualities are largely interconnected and are considered as a whole. To determine them, you can use simple methods.

Analysis of soil texture

To establish the granulometric composition, take a small moistened lump of soil and roll it with your palms into a cord 2-3 mm thick, then roll it into a ring with a diameter of about 2 cm.

If you can’t roll up the cord—it falls apart in your hands into many particles—then the soil is sandy.

If you succeed in rolling the cord, but when twisting it into a ring it falls apart, then the soil is sandy loam.

If, when rolled, a strong cord is obtained, but the ring cracks in several places or breaks up into large parts, then the soil is medium loamy.

If the lump produces a strong cord that easily curls into a ring, only slightly cracking at the edges, then the soil is heavy loam.

If the cord curls into a strong, smooth ring, then you have clay in your hands.

Determination of soil aeration

This indicator is especially important for heavy clay soils, in which, due to high density, reduced aeration is often observed. Without the use of instruments, this indicator can be determined by color. In the presence of oxygen clay soil acquires a characteristic red tint. Under conditions of lack of oxygen, the substrate becomes bluish in color, reminiscent of cement dust or lake silt.

Such areas can occur only locally - in the form of limited islands or inclusions. Sometimes too wet ash-gray clay lies in a continuous layer in areas. The solution may be either the use of drainage or planting moisture-loving plants, which will reduce the amount of water in the soil, which will promote better aeration.

Determination of acidity

There are many methods for this. If special devices and test strips are not available, you can use other methods. Moreover, ready-made store analyzers determine only one type of acidity – actual. But for plants, potential and metabolic acidity are no less important. It happens that the test shows a neutral pH level, and the plants literally “burn”, which clearly indicates.

A more informative field test is phytoindication - that is, determining a parameter based on the prevailing natural vegetation.

Very low pH indicators:

Buttercup, white grass, cotton grass, sphagnum moss, horsetail, small sorrel.

Indicators of weakly acidic substrates:

Anemone lutinica, zelenchuk, oxalis, Ivan-da-Marya, dog violet.

Indicators of neutral soils:

Hemlock stork, green strawberry, Siberian hogweed, meadow foxtail, coltsfoot, soapwort, cinnamon grass.

Alkaline soil indicators:

Crescent alfalfa, chicory, steppe aster.

Determination of hydrological features

This indicator can be approximately determined when digging a pit in your own or neighboring areas. If groundwater is located close to the surface, there will definitely be water in the pit.

Without any measurements, you can independently determine hydrological conditions also from plants. They perfectly show the degree of moisture content of the substrate.

On a waterlogged substrate there is a lot of:

Wild rosemary, wild rosemary, meadow geranium, blueberry, snakeweed, marigold, marsh cinquefoil.

On moderately moist soils there is a lot of:

Lingonberries, Phrygian cornflower, meadow clover, hoofed grass, stone berries.

In dry habitats there are many:

Feather grass, cat's foot, sedum, bearberry.

Determination of soil fertility

This criterion indicates the level of content of main nutrients, primarily nitrogen. Phytoindication can also help any gardener out.

Phytoindicators of low fertility:

Cat's foot, round-leaved sundew, gorse.

Phytoindicators of moderate nitrogen content:

Veronica longifolia, river gravel, angelica, wood sorrel, swimsuit, two-leaved myringue, lungwort.

Phytoindicators of highly fertile, nitrogen-rich soils:

Fireweed, stinging nettle, brome, cinquefoil, raspberry, meadowsweet, meadowsweet, celandine.

I hope that now, knowing how to conduct a soil test on the site, you can’t go wrong with its choice, and if you don’t have much choice and you have to cultivate what’s suggested, you can always correct the soil according to in the right direction. Have a good harvest! See you later, friends!

The most accurate results can be obtained with a comprehensive analysis, which is offered by specialized laboratories. For this you only need to prepare the material, that is, the soil from your plot of land, for analysis, but this must be done correctly, since the degree of accuracy of the results largely depends on this.

A soil sample from the site should be taken before applying fertilizers and liming. IN different places plot of land, you need to make holes to the depth of a spade bayonet or a little deeper. It is this depth that most plants need to freely accommodate and nourish the root system, therefore, the soil must be comprehensively examined in this area. In total, at least 15-20 holes should be dug, which will allow for greater objectivity of the analysis, and thus, at least 15-20 samples should be taken from 100 m2 of site area. Then, sequentially, from the wall of each of the holes you need to scrape off a thin layer of earth with a scoop in the direction from bottom to top and put it in a bucket, after which all the samples are thoroughly mixed in the bucket. At least 1 kg received soil mixture place in a plastic bag and close it tightly.

When submitting soil for analysis to the laboratory, indicate the characteristics of your site, location and the main purpose for which you intend to use it. land plot(growing vegetables, fruit crops or anything else). Based on the analysis obtained, you will be able to accurately determine in which nutrients and microelements the soil especially needs, what fertilizers need to be applied and what measures should be taken to improve the composition of the soil.

An important role in assessing soil quality is played by its appearance, by which one can quite accurately determine the structure, some internal properties and soil quality One of the most important external signs soil is its color. If you dig a hole at least 1 m deep, you will get a soil profile, that is, the structure of the soil in cross-section. On the side wall of the pit, one can successively trace the alternation of soil layers and the change in their color towards the bottom of the pit. The color of the soil is directly related to such characteristics as the level of fertility.

This is a completely logical conclusion, since the appearance of the soil and its fertility are determined by numerous factors that influenced its formation. Dark soils, as a rule, are characterized by a higher level of fertility, since they represent best conditions for the growth of plants and the activity of soil microorganisms than light soils. The color of dark soils is due to the increased content of soil organic matter, humus. It is humus good quality, contained in the soil in sufficient quantities, determines the rich dark color of the soil. However, it is not only humus that provides a particular color to the soil, but also numerous chemical compounds, such as iron oxides, which give the soil brown, reddish, reddish-rusty and yellowish shades. Plates of a bluish-gray or gray color may appear on the soil profile at different depths, which is a poor characteristic of the soil of the site, as it indicates the presence of constant waterlogging of the soil, which results in the formation of ferrous compounds. Such soil will require great efforts to improve, but a lot also depends on
depths of blue clay strata.

In addition to special analysis, there are a number of methods for conducting soil analysis yourself.

Of course, such methods will not produce a chemically accurate assessment of all the characteristics of the soil in a particular area, but they will give you an idea of ​​its main parameters and allow you to make the right decision on further processing and fertilization of the soil. A home mini-laboratory will help with this, which is a set of reagents and indicators, equipped with a color scale for comparative analysis acid-base reaction of the soil using indicator paper and detailed description all possible soil tests. In addition, the soil can be examined visually. This will give you at least a fairly good idea of ​​the structure and composition of the soil.

If you make a hole one or two shovels deep and examine the profile of the cut, then by the color of successive layers you can approximately determine what kind of soil you are dealing with. More often top layer darker than subsequent ones, which indicates a higher content of organic matter or humus in it. Its thickness may vary, but it is advisable that it should not be less than 1015 cm, that is, the depth where plant rooting occurs. Peat soils They are almost black in color due to the high content of organic matter in them. The sandy layer of the earth has a yellowish
gray color, loamy layer - light brown with various shades, clay layer can be different colors- from brown and reddish to whitish.

Manual soil testing

If you are not entirely sure what the composition of the soil in your area is, you can check it in the following way: take a handful of moist, but not wet soil and rub it between your fingers. If the soil structure is granular, if it does not stick together or roll into balls, you have sandy loam or sandy soil.

If the soil is grainy but rolls into a ball or clump, it is sandy loam.

If the soil has a grainy or sticky texture and you can roll it into a sausage between your palms, then you are dealing with oily sandy loam.

If the resulting sausage is flexible, it can be bent into a ring and it will not break, it is clay.

Knowing the structural properties of your soil can help you determine what steps you need to take to improve it.

When examining the soil manually, it is not difficult to see that individual soil particles are completely different from each other. In sandy soils or soils with a high sand content, solid particles are large and coarse and can be clearly felt by touch. The more the soil sticks together, the smaller and thinner its particles are, which indicates a high clay content in the soil. Good soil has a mixed composition of coarse and fine particles, which form into small loose lumps. Soil with a high humus content has a pleasant, healthy smell of forest soil, rotten leaves and grass.

Time to take a soil sample

The accuracy of the analysis also depends on time. A soil sample should be taken early spring or late autumn, that is, before or after the growing season of plants. If the sample is taken in the spring, this must be done before applying fertilizers; if in the fall, then after at least 2 months have passed after the last application of fertilizers and before they are applied for autumn digging.

Acidity.

In order to obtain high yields and use fertilizers more efficiently, every gardener must know what kind of soil he has on his site. Neutralization of acidic soils (liming) is often simply necessary. As is known, soils are strongly acidic (pH 3-4), acidic (pH 4-5), slightly acidic (pH 5-6), neutral (pH 7), alkaline (pH 7-8) and highly alkaline (pH 8-9) .

Most fruits, vegetables and other crops prefer slightly acidic to neutral soils (pH 5.5-7), and some (chokeberry, sea buckthorn, black currant) prefer neutral soils.

The reaction of soils can be approximated by the growing weeds, but in garden plots there is a constant struggle against them, so this factor is difficult to use practically.

On your site, to determine the acidity of the soil, you can use universal indicator paper (TU 16-99 -1181 - 71), used in chemical laboratories to determine reactions various solutions. They sell it in Khimreaktivy stores.

This is a set of 60 or 75 light orange filter strips impregnated with a mixture of indicators that different meanings pH values ​​take on one color or another. Strip length 5 cm, width 1 cm, shelf life 5 years. The paper is accompanied by a standard colored scale with ten multi-colored stripes, above each of which the pH value is indicated. The measurement accuracy of universal indicator paper is up to one pH unit.

Soil for analysis must be taken in different places and at different depths. The reaction of the soil solution must be determined in an aqueous extract. To do this, pour water into a glass or plastic jar. Place the soil in a clean cloth, tie it and lower it into water. The water does not become cloudy. (For one volume of soil, take 4-5 parts of water.)

After 5 minutes, immerse a dry strip of indicator paper in the soil solution for 2-3 seconds or apply a drop of this solution to it. Then take out the paper and immediately compare the color it acquires with the scale. Obtain the pH value of the soil solution.

If the soil is acidic, you need to add ash or lime, chalk or powdered construction cement. Excessive alkalinity can be reduced by adding neutral or acidic soils, and mix everything thoroughly.

In areas with close groundwater levels, soil analysis can be carried out immediately on site. To do this, after rain, simply lower a strip of universal indicator paper into a small hole with settled water and determine the pH. To more accurately determine the soil reaction, you can use Rifan indicator paper. This is also filter paper 8 cm long and 1 cm wide with colored stripes of different colors applied across it. Each color strip indicates the pH value in narrow intervals, for example: 5.8; 6.2; 6.6; 7.0; 7.4.

To determine the pH, dip dry Rifan paper into the soil solution so that all the colored stripes are in the water, and then compare it with a color scale on paper that has digital pH symbols. The same color of the indicator strip with one of the scale strips will indicate the pH value. When determining the soil reaction, you can first use universal indicator paper, and then use Rifan paper to clarify the pH value.

The analysis can also be carried out using acid-base two-color indicator papers: red litmus (color transition of the indicator from red to blue), blue litmus (color transition from red to blue) and neutral litmus (up to pH 5 - red, more 8 - blue).

Red litmus paper in a strongly alkaline solution turns blue, without changing its color in a strongly acidic solution (in the pH range from 4 to 6.4, the color is transitional).

Blue litmus paper in acidic and strongly acidic solutions turns red without changing color in a strongly alkaline solution (in the pH range from 5 to 8, the color is transitional). With a neutral reaction, it acquires a violet-lilac color.

Neutral litmus paper turns red in a strongly acidic solution (pH up to 5), and blue in a strongly alkaline solution (pH more than 8).

Unlike red and blue litmus papers, neutral litmus paper does not change paint in the pH range from 5 to 8.

Thus, for an approximate determination of the soil reaction, you can use acid-base two-color papers, for a more accurate one, universal “rifan” and other indicator papers with narrow pH ranges.

Microbiological analysis - nothing could be easier!

Many people probably know that soil fertility is determined not only mineral composition, but also by those humus-forming organisms that transform organic matter and minerals into a form that plants can perceive. The role of ordinary worms, which process organic residues into humus, is well known. But not everyone knows that along with them, millions of microorganisms live in the soil, which convert organic residues into a humus layer. Invisible microorganisms, bacteria and fungi, constantly processing organic matter, provide plants with 57 percent nutrition.

There are a great many types of such microorganisms. Among them there are also agronomically useful ones, which bind nitrogen, phosphorus, potassium, and microelements, but there are also harmful ones, mainly fungi that infect plants. The peculiarity of damage by microorganisms is that plant diseases do not appear immediately, and are sometimes not visible, so the crop is lost after harvest.

Everyone, of course, would like to know what microorganisms live on their site, and whether it might turn out that the entire crop will be affected by some harmful fungus. Conducting microbiological tests in laboratories is a long and very expensive process.

Simple ways to find out the microbiological composition of the soil at home.

The technique is very simple. Prepare strips of clean cloth or filter paper, or pieces of used photographic film or photographic paper measuring 5x15cm. Then the strips are placed in the soil in the top layer in 3-4 places. This is done like this: we drive the shovel vertically into the soil without removing it, move the layer away, lay the leaf against the hard side, and carefully remove the shovel. Lightly compact the cut. We leave this paper or fabric in the soil for three months. Then we carefully remove the samples, clean them from the soil and, based on the nature of the colonies of microorganisms that destroy fiber, that is, those that grew on the test fabric or paper and contaminated it with some phytopathogens, we determine the condition of the soil.

As a rule, phytopathogenic fungi form colonies of black, gray, violet-crimson color and spread over the entire surface of the sample. If there are black, sooty colonies of the fungus Stachybotrys, which affects all onions, garlic, corn, and cereal straws, then it is necessary to change the crop rotation on the site. This fungus produces a supermycotoxin, which in a very small dose, equal to one millionth of a milligram per kilogram of weight, causes poisoning (stachybotriotoxicosis) in horses, large cattle and man. It is manifested by swelling of the lower part of the head, the appearance of cracks on the lips and viscous drooling. For comparison, the toxicity of pesticides (even the most dangerous ones, causing death) is 5-40 mg/kg of weight. It should be remembered that the toxin of this fungus is not destroyed by high temperature, chemical and mechanical processing.

If purple-crimson colonies develop on the surface of the paper or fabric, then they belong to the fusarium fungus. Toxic effect The mycotoxins of this fungus in humans were known back in 1943. When using grain that has been stored in low temperatures, but infected with this fungus, the “drunken bread” effect occurred. The effect of its toxins is similar to that of alcohol. Fusarium causes root rot of many cultivated plants, and in fruit plants it causes leaf fall and drying out.

If gray round or rounded colonies develop on the surface of the fabric or paper, then they belong to the Alternaria fungus, which causes disease in many plants. It forms brown spots on the surface of the fruit, thereby reducing presentation products.

If the surface of the fabric or paper is yellow, green or pink, then this indicates good development mycobacteria and soil health.

Just don’t think that all microscopic mushrooms are harmful. They are found everywhere. The total number of species of microscopic fungi in soils is from 160 to 300, of which only about 50 percent are toxigenic. Now let's try to determine the nitrate content. This can be judged, first of all, by the development of microorganisms on filter paper placed in the soil. If you need to determine whether there are a lot of nitrates in carrots or cucumbers, then place a plate with filter paper in the top layer between the rows of these crops and leave it for seven days. Then remove it, shake off the soil and inspect it.

If there are one or two colonies of the chaetomium fungus in the form of gray-green convex dots on the filter (these are the fruiting organs of the fungus), it means that the soil is normally provided with nitrate nitrogen, and there will not be a large accumulation of nitrates in the products. In this case, we are dealing with environmentally friendly products.

If colonies of the fungus are scattered throughout the filter, then the soil contains a lot of nitrates and all products in this area are heavily contaminated and unsuitable for use. Such products must be soaked before eating for at least one hour. The same fungus forms fruiting bodies on the outer leaves of cabbage, i.e. it can also be used to determine nitrate contamination of cabbage.

On microbiological methods for determining soil fertilizer needs.

To determine the soil's need for nitrogen fertilizers, it is necessary to take used photographic film, x-ray film or photographic paper.

Place the strips in the soil in the top layer in three or four places under the shovel vertically, pressing them tightly against the wall of the soil. Leave for five days. Then remove it and dip it three times in a bucket of water. If everything has been washed away from the film and it has become transparent, it means that soil microorganisms are highly active. On the surface of the film there is a layer of gelatin, which is a protein. When it decomposes by microorganisms, ammonia is formed. When it interacts with other soil compounds, ammonium forms of nitrogen available to plants are formed. And where the gelatin on the film has completely decomposed, the film has become discolored, there is no need to apply nitrogen fertilizers. If it has not discolored at all and remains black, then you need to add a full dose of nitrogen, about one tablespoon per square meter If the discoloration is partial, you need to apply a dose of nitrogen fertilizers according to the degree of decomposition: 70-50-30 percent.

To determine the soil's need for phosphate fertilizers, you need to put a plate with white cotton cloth or filter paper. Do this in the same way as we described above. Be sure to press the cloth or filter firmly against the soil cut. Leave the fabric in the soil for 30 days. Then remove it, clean it from the soil and see the degree of decomposition. If the film that has been standing nearby for five days has become discolored, and the fabric or filter paper has decomposed by 75-100 percent, then the soil does not need either nitrogen or phosphorus fertilizers.

Do-It-Yourself Soil Test Kit

An option for the lazy - Luster Leaf kits allow you to quickly assess the quality of the soil at home.

Luster Leaf offers kits for nitrogen, phosphorus, potassium and pH testing. To check the pH level, using the markings on the container, add soil and water. Then open the capsule, pour the contents into the bottle and shake it. Now all that remains is to compare the color of the contents with the scale applied to the container.

Testing for nitrogen, phosphorus and potassium levels is a little more complicated. To do this, mix one part soil with five parts water, shake and leave to allow sediment to settle. Then take a dropper and fill the container, open the capsule, pour the contents into the bottle and shake again. Compare the color of the liquid with the scale on the container. Comes with kits detailed instructions, which is preferable to use than brief description given in this article.

Agrochemical soil analysis- an event carried out to determine the degree of provision of the soil with the main elements of mineral nutrition, determine the mechanical composition of the soil, the pH value and the degree of saturation with organic matter, i.e. those elements that determine its fertility and can make a significant contribution to obtaining a qualitative and quantitative harvest.

Talking about agrochemical soil analysis, first of all, we mean control of the content of certain components on agricultural lands and lands intended for growing any crops (farm lands, garden plots, summer cottages and much more).


Soil research
carried out on pre-selected samples. In accordance with current regulations in the field of soil analysis and sampling methods, samples can be collected using the “envelope” method or the “grid” method.

Depending on the area of ​​the territory used and the type of analysis, the sizes of the laid sites also vary. To monitor the condition of agricultural land, for every 0.5 - 20 hectares of territory, at least one test plot measuring at least 10mx10m is laid out. In this case:

The homogeneous cover of the area requires sampling on sample plots of 1 - 5 hectares to determine the content chemicals, structure and properties of soil; sampling on sample plots of 0.1 - 0.5 hectares to determine the content of pathogenic organisms in the soil.

Heterogeneous terrain cover; sampling on sample plots of 0.5 - 1 ha to determine the content of chemicals, structure and properties of the soil; sampling on sample plots of 0.1 ha to determine the content of pathogenic organisms in the soil.



Sampling scheme for agrochemical soil analysis
looks like this: taking into account the above recommendations, a test site is laid out on the territory. Along the diagonals running from one corner of the site to the other corner, point samples of the topsoil are taken, the mass of which should not be less than 200 g. We mix the resulting spot samples with each other, thereby obtaining the combined sample we need. A pooled sample consists of at least 5 point samples taken from one sample site. The weight of one combined sample must be at least 1 kg.

Agrochemical soil analysis reflects the condition of the soil according to the following main indicators

- Main agrochemical indicators (6 indicators):

pH - soil acidity- this is a property of soil caused by the presence of hydrogen ions in the soil solution and exchangeable ions of hydrogen and aluminum in the soil absorption complex.

Soil organic matter- this is the totality of all organic substances in the form of humus and the remains of animals and plants, i.e. important component soil, representing a complex chemical complex of organic substances of biogenic origin and determining the potential of soil fertility.

Granulometric composition - mechanical structure soil, which determines the relative content of various particles, regardless of their chemical and mineral composition.

Hydrolytic acidity- soil acidity, manifested as a result of exposure to hydrolytic alkaline salt (CH 3 COONa). Determining hydrolytic acidity is important when solving practical problems related to the use of fertilizers, liming, soil phosphorite treatment and other agrochemical methods.

Sum of absorbed bases- the degree of soil saturation with bases, shows what proportion of the total amount of substances retained in the soil is accounted for by absorbed bases.

Nitrates- total content of nitric acid salts. These substances are hazardous to humans and can accumulate in products agriculture due to excess nitrogen fertilizers in the soil.

- Macroelements:

Mobile phosphorus- form of phosphorus assimilated by plants (P 2 O 5). A source of food for plants, a carrier of energy. It is part of various nucleic acids, and its deficiency sharply affects plant productivity.

Exchangeable potassium- a mobile form of potassium in the soil that plays important role in plant nutrition. Plays a significant role in plant life, affecting the physical and chemical properties of plants.

Nitrate nitrogen- nitrogen contained in the soil in the form of nitrates, used by plants to form amino acids and proteins.

Ammonium nitrogen- nitrogen is an ammonia compound that is used by plants for the synthesis of amino acids and proteins.

Iron- an element involved in the formation of chlorophyll, being integral part green pigment. Regulates the processes of oxidation and reduction of complex organic compounds in plants, plays an important role in plant respiration, as it is part of respiratory enzymes. Participates in photosynthesis and the transformation of nitrogen-containing substances in plants.

- Microelements:

Cobalt- a microelement necessary not only for plants, but also for animals. It is part of vitamin B 12, the deficiency of which disrupts metabolism - the formation of hemoglobin, proteins, nucleic acids is weakened, and animals become ill with acobaltosis, tabes, and vitamin deficiency.

Manganese- a microelement that takes part in redox processes: photosynthesis, respiration, in the absorption of molecular and nitrate nitrogen, as well as in the formation of chlorophyll. These processes occur under the influence of various enzymes, and manganese acts as an activator of these processes.

Copper- a trace element necessary for plant life in small quantities. However, without copper, even seedlings die. The gross content of copper in soils ranges from 1 to 100 mg/kg of dry matter.

Molybdenum- a microelement that plays an exceptional role in plant nutrition: it is involved in fixation processes molecular nitrogen and restores nitrates in plants. With its deficiency, plant growth is sharply inhibited; due to disruption of chlorophyll synthesis, they acquire a pale green color (leaf blades are deformed and leaves die prematurely). Legumes and vegetable plants (cabbage, leafy vegetables, radishes) are especially demanding of the presence of molybdenum in the soil in an accessible form.

Zinc- a microelement involved in many physiological and biochemical processes in plants, being mainly a catalyst and activator of many processes. Lack of zinc leads to metabolic disorders in plants.

Nickel- a microelement that takes part in enzymatic reactions in animals and plants, necessary for normal development living organisms. Increased nickel content in soils leads to endemic diseases - ugly forms appear in plants, and eye diseases in animals associated with the accumulation of nickel in the cornea.

- Toxic elements:

Cadmium- one of the most toxic heavy metals is classified as hazard class 2 - “highly hazardous substances”. The source, which is in the soil, is industry.

Lead- a heavy metal with high toxicity. The presence of elevated concentrations of lead in the air and food poses a threat to human health. Automobile exhaust accounts for about 50% of total inorganic lead.

Chromium- connection of the 1st hazard class; a trace element found in trace amounts in living and plant organisms. Excess chromium in soils causes various diseases in plants.

The presence of chromium in soils (up to 50-70 mg/kg of dry soil) determines its movement along the food chain: soil - plant - animal - human. The main sources of chromium and its compounds into the atmosphere are emissions from enterprises where chromium and its compounds are mined, received, processed and used. Active dispersion of chromium is associated with the combustion of mineral fuels, mainly coal. Significant amounts of chromium enter the environment through industrial wastewater.

Mercury- highly toxic chemically resistant element. Refers to dispersed elements (rare). The amount of mercury released into the environment in the current century as a result of anthropogenic activities is almost 10 times higher than natural releases and amounts to 57,000 tons.

Arsenic- microelement. Referred to as scattered elements. Arsenic is a trace element necessary for the functioning of living organisms. At elevated concentrations, arsenic has a toxic effect on living organisms. The content of arsenic in the soil determines its content in natural waters.

Benz-a-pyrene- a complex chemical compound related to the so-called PAHs (polyaromatic hydrocarbons). An element of hazard class 1, formed during the combustion of hydrocarbons, regardless of their state of aggregation(liquid, solid, gaseous). Is the most common chemical carcinogen environment, dangerous to humans, even at low concentrations, since it has the property of accumulation in the human body. In relation to the natural environment, and directly to its factors, we can say that the highest concentrations are in the air and soil. Given this, benz-a-pyrene is very easily transported throughout the food supply. Each subsequent level of the food chain is accompanied by significantly increased concentrations of the carcinogen.

Petroleum products- hydrocarbons, or more correctly, a mixture of them, which may include more than 1000 independent organic substances. Each of these compounds can be considered as an independent toxic substance. In practice, the assessment of pollution of a particular object with petroleum products is carried out in the following areas: the content of light fractions (considered the most toxic for living organisms and the environment, but due to their evaporation, they ensure rapid self-purification of the soil), the content of paraffins (relatively toxic substances, mainly affecting physical properties soil), sulfur content (determining the degree of hydrogen sulfide contamination of the soil).

- Bacteriology:

Coliform index- shows the number of bacteria of the E. coli group per 1 g of soil. Coliforms are saprophytes of the intestines of humans and animals. Their detection in the external environment indicates its fecal contamination, therefore E. coli is classified as a sanitary indicator microorganism.

Enterococcus index- a sanitary-bacteriological indicator characterizing the quantitative content of bacteria of the genus Enterococcus (p. Enterococcus) in 1 gram of soil, also known under another term - “fecal streptococci”.

Pathogenic bacteria, incl. salmonella- a sanitary-bacteriological indicator characterizing the quantitative content of bacteria in 1 gram of soil, capable of causing infectious diseases under appropriate conditions.

Agrochemical soil analysis is of no small importance. It promotes the adoption of expedient and thoughtful decisions that contribute to the organization of measures to increase efficiency and increase the fertility of the lands used. Specification of tasks for a particular type of cultivated crop will not take long and will allow you to get a rich harvest - the desired result of any farmer.

A soil sample should be taken before applying fertilizers and liming. In different places of the land, holes are made to the depth of a spade bayonet or a little deeper (25-30 cm). This is the depth that most plants require to freely accommodate the root system.

You should dig at least 15-20 holes, which will allow you to achieve more accurate results. From 100 m2 of plot area you need to take at least 15-20 samples. Then, from the wall of each hole, you need to scrape off a thin layer of earth with a shovel in the direction from bottom to top and put it in a bucket. After this, mix all samples thoroughly. At least 1 kg of the resulting soil mixture is placed in a plastic bag and closed tightly.

When submitting soil for analysis to the laboratory, indicate the characteristics of your site, its location and the main purpose for which you intend to use the land (growing vegetables, fruits or other crops). This will allow you to receive more accurate analysis and appropriate recommendations.