Table of contents:
- The main processes of soil formation
- Soil structure and main methods of its improvement
- Characterization of soils by mechanical composition
- What is acidity and how to determine it
Video: How To Improve Soil Structure And Increase Its Fertility
- The main processes of soil formation
- Soil structure and main methods of its improvement
Characterization of soils by mechanical composition
- Clay soils
- Loamy and sandy loam soils
- Sandy soils
- Calcareous soils
- Peat soils
- What is acidity and how to determine it
- Related Videos
In the previous articles of the cycle "Organic farming: main features" and "Stop destroying the earth by digging and weeding", we considered the soil from the point of view of gardeners-organists, who treat it as a living being and believe that the main indicator of fertility is the presence in the ground a large number of beneficial microorganisms and earthworms, which are the main producers of humus. Today we will look at the soil from the perspective of modern science - we will give a precise definition and talk about the processes of its formation, as well as consider the main mechanical and chemical characteristics.
According to the definition of soil scientists, soil is the surface layer of the land of our planet, which arose as a result of the impact on rocks of atmospheric phenomena, sunlight and various living organisms, which led to significant changes in their structure and composition. The soil is considered a unique natural formation, possessing only its inherent properties, the most important of which is fertility. It is precisely the presence in its composition of nutrients and water reserves necessary for the development of plants that the soil, as a natural body, differs from other natural bodies, for example, stone. It is the most important component of almost all biocenoses of the planet - various ecological connections of most living organisms and humans with the hydrosphere, lithosphere and atmosphere pass through the soil cover.
The main processes of soil formation
The rocks that have covered the Earth's surface since its formation have been destroyed over millions of years under the influence of atmospheric phenomena (wind, sunlight, precipitation). Massive stones gradually passed into a crushed state, their mineral and chemical composition changed. Sand and clay are prominent examples of fractured rocks.
As a result of these transformations, rocks acquired new properties, becoming more permeable to air and water. The stones, crushed to a fine state, acquired the ability to retain moisture, which made them suitable for the vital activity of various bacteria and plant organisms. The crushed rocks were gradually enriched with the products of their vital activity and dead plant residues, the decomposition of which under the influence of oxygen caused complex biochemical processes. This is how the ash and nitrogen food accumulated on the surface of the earth's crust, which, in fact, led to the formation of the soil layer. Thus, it becomes clear that the composition of the soil today is determined by the mineral components corresponding to the composition of the bedrock, and also depends on the characteristic organic components.
Science has proven that the formation of the soil is directly affected by the natural conditions in which it occurs. Today, there are several main factors that affect the formation of the soil layer:
- parent (parent) rocks
- vegetation and animals characteristic of a particular area
- climatic conditions and terrain
- groundwater action
- human activity
All currently existing soil types were formed from rocks, therefore the mineral component of any soil, as a rule, contains elements that were part of the parent rock.
The climate also plays an important role in the formation of the soil layer. Average annual temperatures and the amount of precipitation in a certain period of time determine certain processes of soil formation. And the presence of one or another vegetation, as well as the habitation of certain species of animals, depends on natural conditions.
It is difficult to overestimate the influence of vegetation on the process of soil formation. Due to the vital activity of plants, the top layer of the earth is enriched with nutrients, and as a result of the decomposition of their remains, humus accumulates in the earth. He, in turn, serves as food for soil inhabitants, who are the main "producers" of humus. What humus is, RMNT. RU told in detail in the article "Stop destroying the earth by digging and weeding". The vegetation cover is capable of influencing microclimatic conditions. For example, in the forest, in comparison with the steppe territories, the air temperature is always lower, and the humidity is higher, here the wind strength is reduced, more snow accumulates. All this cannot but affect the soil-forming process in one way or another.
Various biological and chemical processes occurring in the soil are impossible without the influence of water. That is why groundwater has a direct impact on soil-forming processes. Where they are located high, the water and air regime changes, the soil is enriched with certain chemical compounds. In waterlogged soil, there is a lack of oxygen, which negatively affects the vital activity of microorganisms and worms.
Today's active economic activity, as a rule, negatively affects the processes of soil formation. Deforestation, deep plowing, the use of a huge amount of mineral fertilizers leads to a change in chemical and mechanical characteristics, as a result, natural processes are disturbed, and fertility is greatly reduced.
Soil structure and main methods of its improvement
Soil composition has four main components:
- mineral base makes up 50-60% of the total volume
- organic matter - about 10%
- air - from 15 to 25%
- water is contained in the soil in an amount of 25 to 35%
According to the definition of modern science, the structure of the soil is its ability to disintegrate into particles of different shapes, sizes and qualitative composition. Soil structure is today considered one of the main indicators of fertility. The structured soil is well permeable and retains moisture and oxygen, which creates optimal conditions for the growth and development of garden crops. In addition, structured soil is easy to cultivate.
Conduct an experiment - take a small layer of earth with a shovel, toss it up and catch it again with a shovel. The soil will crumble into separate pieces, similar to grain or nuts - these will be its structural elements. The most valuable indicator of the quality of the soil layer is particles of 0.25–10 mm in size, the size from 0.05 to 0.25 mm also speaks of a good indicator of fertility. Depending on this, the soils are divided into structural (loamy and sandy loam), low-structure and structureless (heavy clay soils). We will talk about the mechanical composition of soils a little later.
An important characteristic of the soil structure is its porosity, which provides favorable water and air conditions. The optimal indicator of porosity is 50% of the soil volume. The lower this indicator, the less the soil contains air and moisture, and the worse the conditions for plant growth in it.
Structural soil is loose, has a low density and significant porosity, its cultivation does not require much physical effort. The particles here are characterized by the presence of non-capillary pores, which contribute to excellent conduction and moisture retention. The gaps between particles in a structural soil are always filled with oxygen. In such a land, seeds quickly sprout and seedlings take root, plants do not lack nutrients, air and moisture.
In structureless soil, all the elements lie very tightly to each other; only capillary pores are formed here. Therefore, water penetrates inside extremely slowly, a significant part of it evaporates. In such a land, as a rule, two extremes are observed - either excessive or insufficient moisture. An excess of water results in a lack of oxygen. Under these conditions, anaerobic processes occur, leading to the loss of nitrogen and the production of ferrous oxides, manganese and phosphorus, harmful to plants. And with insufficient air moisture in the soil, there is a lot, and there is practically no moisture, which also negatively affects the growth of crops.
To improve the soil structure, it is necessary to take certain measures aimed at changing the mechanical composition, for example, to add clay to sandy soils, and sand to clay soils.
The main agrotechnical methods for increasing the structure of the land include: sowing green manure, applying organic fertilizers and compost, including mulching. All these methods are aimed at creating favorable conditions for the life of soil inhabitants, the presence of which leads to an increase in fertility. We talked about all this in more detail in the article “Organic farming. Let's make the land good."
Characterization of soils by mechanical composition
The main task of any gardener is to obtain a stable high-quality crop with a minimum investment of time, effort and material resources. In order for the plants to feel good, it is necessary, first of all, to understand what is the mechanical composition of the soil on your site. The basic techniques of cultivation and the choice of the most suitable crops will depend on this. According to the mechanical composition, the following main types of soils are distinguished today:
- loamy and sandy loam
In order to determine what type of soil prevails in the garden, it is necessary to observe the land during periods of heavy rainfall or during a drought. It should be noted that on many land plots a combination of several types is sometimes found, so it is extremely important to study the characteristics of each of them.
If after a heavy rain puddles remain on the soil surface for several hours, and in hot dry weather the earth is "taken" with a hard crust, then we can safely say that the soil on the site is clayey. It is felt in the hands as a dense substance, from which, when wet, you can easily mold various figures.
The main characteristic of this type is its lack of structure or complete absence of structure. Such soil is extremely difficult to loosen, and in a rainy period it is generally impossible, since it spreads underfoot. Terms of work here in spring are limited due to the fact that the clay soil slowly warms up and dries out. Given the lack of structure, plants constantly experience either a lack of moisture or an excess of it, which negatively affects their growth and development.
In areas with clay soil, only those plants that like excess moisture, for example, some varieties of roses, raspberries, rutabagas, cherries, feel good. It is recommended to plant vegetables on such land only after carrying out measures to improve the soil structure.
You can improve clay soil by adding ash and coarse sand to it, which will contribute to loosening. Application of organic fertilizers, compost, mulching and green manure will make the alumina more fertile and structured. Beans, peas, almost all types of cabbage, potatoes, most shrubs and fruit trees feel great on the clay lands cultivated in this way.
Loamy and sandy loam soils
These types of soils are considered the most fertile and suitable for growing, both various vegetable crops and the establishment of gardens and vineyards. If after rain the water is absorbed into the ground quickly enough, and, at the same time, the humidity lasts for a long time, then we can say that the soil in your garden is loamy or sandy loam. Loams are composed of clay and sand in a percentage ratio of 70 to 30, respectively. The highest quality soil is considered to be where large grains of sand and silt particles are present.
Sandy loam soil consists of clay for about 20%, and of sand for 80-90%. This is also a good combination, however, it should be borne in mind that if the amount of sand exceeds the specified values, then the quality of the soil is significantly reduced.
Loams and sandy loams are distinguished by a highly structured composition, good air and water permeability. These types of soils are rich in minerals necessary for plants, which contributes to obtaining high quality yields. It is a pleasure to work on such soil, it is remarkably loose, has a dark color and is rich in humus. The wet loams and sandy loams are grainy to the touch and smear your hands a little.
Loamy and sandy loam land does not need any additional improvement, you can easily grow a rich harvest of any crop on it. And if such soil is protected and cultivated, following the principles of organic farming, described in the article “Organic farming. Main features”, then she will pamper your children, grandchildren and great-grandchildren with environmentally friendly crops.
If the soil quickly absorbs moisture, but also quickly evaporates it, then we should talk about the sandy type of soil. Such soils have both advantages and disadvantages.
The main advantages include low labor intensity during processing - they practically do not need loosening. Good air permeability provides oxygen access to the roots, which has a positive effect on the development of the root system. Sandy soils are very warm, they warm up much earlier than others, so they are ideal for growing early vegetables and fruits.
The disadvantages of sandstones are as follows: the sand does not retain moisture well, which does not linger in the root area, but seeps either deeper or evaporates. Lack of rain or watering can lead to drought very quickly. Excellent air permeability promotes the decomposition of nutrients into mineral components in a form inaccessible to plants, and rains and irrigation easily wash out organic matter, and humus does not accumulate. The salts of metals and alkalis are also easily washed out from sandy soils, which leads to their strong acidification. We will talk in more detail about the chemical composition of soils a little later.
The application of biological fertilizers in sufficiently large quantities will help to increase the fertility of sandstones. Planting green manures will improve the structure of the soil and saturate it with additional organic residues, prevent the leaching of nutrients. Mulching with any materials at hand will help to save soil moisture, and the layer of mulch in this case should be at least 7 cm.
Sandy soil can be turned into sandy loam by adding clay to it at the rate of 3 buckets per 2 square meters. m every year for 5-6 years. The clay must be in a powdery dry state, otherwise it will not mix properly with the sand. This method of improvement is a task that requires a lot of time, effort and money.
On well-treated sandy soils described above, potatoes, various varieties of onions, and almost all root crops grow well. Tomatoes will love it here too.
This type of soil can be identified by the following features: the rapid absorption of water after rainstorms, and with the onset of dry hot weather, the ground takes on an off-white or grayish tint.
Calcareous soil resembles sandy soil in structure and properties. It also does not retain moisture, and the leaching of nutrients greatly reduces fertility. Calcareous soil differs from sandstone by the presence of a large amount of calcium salts, in other words, lime, and has a pronounced alkaline reaction.
The application of organic fertilizers and green manure will help to replenish the amount of nutrients and improve the soil structure, a thick layer of mulch will save moisture. It is easy to work on this land - it, like sandy, practically does not require loosening.
Calcareous soils with a sufficient amount of organic fertilizers and appropriate processing are suitable for growing most types of plants, the only exception is potatoes, which prefer soils with slightly increased acidity.
This type of soil is extremely rare in vegetable gardens and household plots, where there used to be swamps. With ideal cultivation, peatlands can produce stable yields for a long time.
Drained peat soils are rich in organic matter, but poor in nitrogen and other minerals in a form available to plants. To accelerate the conversion of minerals into such soil, it is necessary to add sand and clay at the rate of 10 square meters. m - 20 buckets of clay and 40 buckets of sand. Clay, as in improving the structure of sandy soils, should have a dry powdery consistency. To accelerate the conversion of nitrogen, it is also recommended to add compost (10–15 kg per 10 sq. M.) To the peat soil.
Peat bogs have a porous structure and retain moisture remarkably, such land practically does not require loosening, however, the increased acidity of the peat soil can cause a number of such dangerous fungal diseases as cruciferous keels.
Here potatoes and bush berries grow well, strawberries and strawberries feel good. When planting vegetables, it is necessary to pay attention to the level of groundwater, if they are at a height of less than 1 meter to the surface, then crops should be planted on raised ridges. How to organize them correctly is described in detail in the article "How to lay smart beds". Due to the high water table, it is not recommended to plant fruit trees on peat soils.
What is acidity and how to determine it
Acidity is the most important characteristic of the chemical properties of various soils. Increased or, conversely, decreased acidity can cause poor health in many garden crops.
Acidity is measured as a unit of pH (acidity level), depending on which soils are divided into acidic (pH 4–6.5), neutral (pH 6.5–7) and alkaline (pH 7–9). This scale has extreme values from 1 to 14, however, in Europe, such indicators are practically not found.
How to practically determine the acidity of the soil in a personal plot? You can, of course, take her samples to the laboratory. But not always and not everyone has such an opportunity. You can also buy a special device for determining acidity (pH tester) from garden centers and take measurements with it.
However, the approximate pH level can be determined in simpler ways. If you pour a piece of land with ordinary table vinegar 9% and it "sizzles" - the soil on the site is alkaline.
You can determine the acidity level as follows: dig a hole wide and deep on a bayonet, cut a thin layer of earth around the perimeter of which, mix it well and moisten it with rain or distilled water. Then the earth must be squeezed together with litmus paper in hand. If the paper turns red, the soil is highly acidic, if pink, it is moderately acidic, and the yellow color will be an indicator of slightly acidic soil. If the litmus paper turns green-blue, we can safely say that the pH level is approaching neutral, blue means neutral acidity, and green means that the soil in the garden is alkaline.
The acidity of the soil can be accurately determined by some types of weeds growing on the site. For example, sorrel, creeping buttercup, plantain, field horsetail, tricolor violet loves acidic soil. If in the garden you notice medicinal chamomile, wheatgrass, coltsfoot, clover and sow thistle, then the acidity is most likely neutral or slightly acidic. Field bindweed, poppy, larkspur indicate alkaline soil.
All the plants we plant in our backyards have different pH levels. According to this principle, four groups are distinguished:
- Crops that prefer neutral or slightly alkaline soil and do not tolerate acidic soils - currants of all varieties, any kind of cabbage, beets.
- Plants that thrive on soils with a slightly acidic reaction are legumes (peas, beans, etc.), onions, cucumbers, rose hips.
- Garden crops that calmly tolerate the soil of moderate acidity - tomatoes, carrots, pumpkin, turnip, gooseberries, raspberries.
- Sorrel and potatoes like increased acidity.
To neutralize soils with high acidity, liming is recommended every 4–5 years with the introduction of slaked lime, dolomite flour, and furnace ash into the soil. These materials are brought in in the fall per sq. m:
- sandy loam and loamy soils - 3 kg;
- heavy loam and clay soil - 4.5–5 kg.
It should be noted that liming cannot be carried out simultaneously with the introduction of manure, since such a combination will contribute to the loss of nitrogen, which is contained in large quantities in the manure.
There are times when the soil in the garden needs to be acidified, for example, if the soil is of a calcareous type. This is especially true when planting potatoes or conifers. To increase the acidity, high peat or coniferous soil from the forest can be added to the planting pits or furrows.
From the foregoing, it can be concluded that in order to obtain a high-quality high yield, it is necessary not only to observe the agricultural techniques necessary for each specific type of cultivated plants, but also to carefully study the chemical and mechanical composition of the soil, its structure and characteristics. Only an attentive and careful attitude to the land will allow you to pamper your family with ecologically clean vegetables and fruits from year to year.