Soil is a living organism
May 25, 2018
Soil is a living organism consisting of countless microscopic living things. The number and diversity of living microorganisms in the soil is immeasurable. In 1 gram soil contains billions of bacteria, fungi, algae and other organisms, and in addition, a great many earthworms, lice, centipedes, snails and other soil organisms that, as a result of the metabolism process, process dead protein organisms and other organic residues innutrients available for assimilation by plants. Due to their activity in the soil, humus is formed from the initial vegetable and protein material, from which, as a result of the connection with water and oxygen, plant nutrients are released. A loose soil structure is also achieved largely due to the activity of
soil organisms, which naturally mix mineral and organic substances, producing a new enriched substance. This greatly increases the fertility of the soil. The study of soil animals is carried out by a special branch of science - soil zoology, which was formed only in our century. After specialists developed methods of recording and fixing animals, which is associated with considerable technical difficulties, the eyes of zoologists appeared a whole kingdom of beings, diverse in structure, lifestyle and significance in natural processes occurring in the soil. On biological diversity, the animal world of the soil can be compared only with coral reefs - a classic example of the richest and most diverse natural communities on our planet.
Among them are large invertebrates such as earthworms, and microorganisms that can not be seen with the naked eye. In addition to small sizes( up to 1 mm), most soil-dwelling invertebrates have an unobtrusive coloring of the body, whitish or gray, so they can be seen only after special treatment with fixatives, magnifying glass or microscope. Microorganisms form the basis of the animal population of the soil, the biomass of which reaches hundreds of centners per hectare. If we talk about the number of earthworms and other large invertebrates, then it is measured in tens and hundreds per square meter, and the number of small and microscopic organisms reaches millions and billions of individuals.
For example, the simplest and roundworms( nematodes) with a body size of up to 0.01 mm in terms of their physiology are typically aquatic creatures capable of breathing oxygen dissolved in water. The smallest dimensions allow them to be content with microscopic droplets of moisture filling narrow soil cavities. There worms move around, find food, multiply. When the soil dries up, they are able to remain in the inactive state for a long time, covering themselves with a dense protective shell from the solidifying precipitates.
From soil organisms larger can be called soil mites, springtails, small worms - the closest relatives of earthworms. These are already real land animals. They breathe atmospheric oxygen, occupy air intrasoil cavities, root passages, burrows of larger invertebrates. Small size, flexible
Soil organisms are a vital link in a closed cycle of metabolism. Thanks to their livelihood, all products of organic origin decompose, processed and acquire a mineral form accessible to plants. Mineral substances dissolved in water come from the soil to the roots of the plants, and the cycle begins first
body allows them to use even the narrowest intervals between soil particles and penetrate deep horizons of dense loamy soils. For example, armor pliers go deep into 1.5-2 m. For these small soil inhabitants, the soil is also not a dense mass, but a system of passages and cavities connected together. Animals live on their walls, as in caves. Overmoistening of the soil is as unfavorable for its inhabitants, as well as drying out. Well-defined soil invertebrates with body size larger than 2 mm. Here you can find a variety of groups of worms, terrestrial mollusks, crustaceans( moccasins, amphipods), spiders, haymakers, spoon-noskorpions, millipedes, ants, termites, larvae( beetles, Diptera and Hymenoptera insects), butterfly caterpillars Earthworms and some insect larvaestrongly developed musculature. By contracting the muscles, they increase the diameter of their body and push the soil particles apart. Worms swallow the earth, pass it through their intestines and move forward, as if "eating" through the soil. Behind them leave their excrement with the products of metabolism and mucus, abundantly secreted in the intestinal cavity. These mucous lumps of worms cover the surface of the course, strengthening its walls, so such moves are long preserved in the soil.
A larvae of insects have special formations on the limbs, the head, sometimes on the back, with which they act like a shovel. For example, the bear's legs are turned into strong digging tools - they are expanded, with jagged edges. These scrapers are able to loosen even very dry soil. In the
larvae, which digs the courses to a considerable depth, the upper jaws serve as the loosening tool, which look like triangular pyramids with a dentate vertex and with powerful ridges along the sides. The larva strikes these jaws in a soil lump, breaks it into small particles and rakes them under itself. Other large inhabitants of the soil live in existing cavities. They differ, as a rule, by a very flexible thin body and can penetrate into very narrow and twisting passages. Digging activity of animals is of great importance for the soil. The system of strokes improves its aeration, which favors the growth of roots and the development of aerobic microbial processes associated with humification and mineralization of organic material. No wonder Charles Darwin wrote that long before man invented the plow, earthworms learned to correctly and well work the land. He dedicated to them a special book "The formation of the soil layer by earthworms and observations of the way of life of the latter."
The main role of soil organisms is the ability to quickly process plant residues, manure, household waste, turning them into a high-quality natural organic fertilizer biohumus. In many countries, including ours, worms have learned to breed on special farms for obtaining organic fertilizers. The following examples will help evaluate the contribution of invisible soil workers to the structure of its structure. Thus, the ants building soil nests emit more than a ton of soil per hectare to the surface from deep soil layers. For 8-10 years, they process almost the entire horizon they occupy. And the deserted lice raises from the depth of 50-80 cm to the surface soil, enriched with elements of mineral nutrition of plants. Where there are colonies of these lice, the vegetation is higher and thicker. Rain worms can process up to 110 tons of land per hectare per year.
Moving in the ground and feeding on dead plant remains, animals mix organic and mineral soil particles. By dragging land litter into deep layers, they thereby improve the aeration of these layers, promote the activation of microbial processes, which leads to soil enrichment with humus and nutrients. It is the animals that create the humus horizon and soil structure by their activity.
The role of earthworms in the biological life of the soil
Earthworms loosen the soil, penetrating unlike other soil organisms that can live only in one soil layer, in different soil layers. Through the worm holes, air and water penetrate to the roots of plants.
Earthworms help enrich the soil with oxygen, which prevents the decay of organic material
: Earthworms absorb organic residues, along with which mineral particles, clay particles, soil algae, bacteria, microorganisms enter the digestive tract. There, this heterogeneous material is mixed and processed, thanks to metabolic processes, is supplemented by secretions of the intestinal microflora of the worm, acquiring a new state, and then in the form of a litter it enters the soil. This qualitatively improves the composition of the soil and gives it a glued lumpy structure.
The man has learned to cultivate the soil, fertilize it and receive high yields. Does this change the activity of soil organisms? To some extent yes. But with intensive land use by modern methods, when soil is overloaded with chemicals( mineral fertilizers, pesticides, growth stimulants), with frequent violations of its surface layer and compaction by its agricultural machines, deep disturbances of natural processes occur that lead to gradual degradation of the soil and a decrease in its fertility. Overestimated amounts of mineral fertilizers poison the earth and kill its biological life. Chemical treatments destroy not only pests, but also useful animals in the soil. It takes years to restore this damage. Today, in the period of ecologicalization of our thinking, it is worthwhile to consider the criteria for assessing the damage caused by the harvest. Until now, it was considered to be only losses from pests. But let's calculate the losses caused to soil itself from the death of soil-formers.
To preserve the soil, this unique natural resource of the Earth, capable of self-restoration of its fertility, it is first of all necessary to preserve its fauna. Soil organisms, soil-formers do what a man can not do with his powerful technique. They need a stable environment. They need oxygen in the system of performed moves and the stock of organic remains, shelters and moves that are not violated by man. Reasonable farming, sparing methods of soil cultivation and maximum rejection of chemical plant protection means the creation of conditions for preserving the living biomir of the soil - the guarantee of its fertility.
Nutrients in the
soil composition All the plant components necessary for life can be obtained from the soil only in mineral form. Nutrients with which the organic mass is rich, humus and organic fertilizers can be assimilated by plants only after the completion of the decomposition of organic compounds or their mineralization.
The presence in the soil of a sufficient number of nutrients is one of the main factors for the successful development of plants. Its above-ground part, root system, flowers, fruits and seeds of plants are built from organic substances: fats, proteins, carbohydrates, acids and other substances produced by the green leaf mass of plants. To synthesize organic substances, plants need ten main elements, which are called biogenic. Biogenic chemical elements are constantly included in the composition of organisms and perform certain biological functions that ensure the viability of organisms. Biogenic macroelements include carbon( C), calcium( Ca), iron( Fe), hydrogen( H), potassium( K), magnesium( Mg), nitrogen( N), oxygen( O), phosphorus( P), sulfur(S).Some of these elements are obtained from the air from the air, for example, oxygen and carbon, hydrogen gets by the decomposition of water in the process of photosynthesis.
Nutrient exchange process
Nutrients play a crucial role in the cyclic process of metabolism, providing vital activity of plants. Water dissolves nutrients and trace elements, creating a soil solution that is assimilated by the roots of plants. Solar energy promotes the transformation of nutrients as a result of the process of photosynthesis, which in turn depends on the presence in the plant tissues of a number of microelements involved in the formation of the colored substance of chlorophyll
for, the remaining elements come to the plant solely from the soil in the form of dissolved in water compounds, the so-called soil solution. If in soil there is a serious lack of any of the elements, the plant weakens and develops only up to a certain stage, until it exhausts its internal biological reserve of the element existing in the tissues of the plant. After this stage, the plant may die. In addition to biogenic macroelements for the development of the plant, trace elements are required, usually contained in very small quantities, but nevertheless play an important role in the processes of metabolism. The microelements include: aluminum( A1), boron( B), cobalt ( Co), copper( Cu), manganese( Mn), molybdenum Mo), sodium( Na), silicon( Si), zinc( Zn).Hei-excess or excess micronutrients leads to metabolic disorder, which results in
lagging behind in plant growth and development, yield reduction and other consequences. Some of these micronutrients are not vital and often stand out by researchers in a group of so-called "useful elements."Nevertheless, their presence is required for the full development of the plant. All components must be present in the nutrition of the plant in a balanced form, since the absence of even one of the main elements, such as nitrogen, phosphorus, potassium or calcium, inevitably leads to the inadequacy or impossibility of assimilation by the plant of the remaining three elements, as well as other nutrients. That is why the presence of all elements is so important for the full assimilation by the plant of the entire nutritional complex.
The ability of plants to absorb nutrients from the environment is determined by the quality and volume of the root system. Plants absorb nutrients throughout the growing season, but unevenly. The need for plants in nutrients varies in different periods of development. In the period of intensive growth, plants are particularly in need of nitrogen, during flowering and fruiting, the need for phosphorus and potassium is increasing. Assimilated nutrients are selectively fixed in various organs of plants.