Nitrogen- this is the main nutrient element for all plants: without nitrogen, the formation of proteins and many vitamins, especially B vitamins, is impossible. Plants absorb and assimilate nitrogen most intensively during the period of maximum formation and growth of stems and leaves, so the lack of nitrogen during this period affects primarily on plant growth: the growth of lateral shoots is weakened, leaves, stems and fruits are smaller, and the leaves become pale green or even yellowish. With a long-term acute lack of nitrogen, the pale green color of the leaves acquires various tones of yellow, orange and red depending on the type of plant, the leaves dry out and fall off prematurely, which limits the formation of fruits, reduces the yield and worsens its quality, while fruit crops ripen worse and the fruits do not acquire normal color. Since nitrogen can be reused, its deficiency appears first on the lower leaves: yellowing of the leaf veins begins, which spreads to its edges.
Excessive and especially one-sided nitrogen nutrition also slows down the ripening of the crop: plants produce too much greenery to the detriment of the marketable part of the product, root and tuber crops grow into tops, lodging develops in cereals, the sugar content in root crops decreases, starch in potatoes, and Vegetable and melon crops may accumulate nitrates above the maximum permissible concentrations (MPC). With an excess of nitrogen, young fruit trees grow rapidly, the beginning of fruiting is delayed, shoot growth is delayed, and the plants face the winter with unripe wood.
According to their nitrogen requirements, vegetable plants can be divided into four groups:
first - very demanding (cauliflower, Brussels sprouts, red and white late cabbage and rhubarb);
second - demanding (Chinese and early white cabbage, pumpkin, leeks, celery and asparagus);
third - medium-demanding (kale, kohlrabi, cucumbers, head lettuce, early carrots, beets, spinach, tomatoes and onions);
fourth - low-demanding (beans, peas, radishes and onions).
The supply of soil and plants with nitrogen depends on the level of soil fertility, which is primarily determined by the amount of humus (humus) - soil organic matter: the more organic matter in the soil, the greater the total supply of nitrogen. Soddy-podzolic soils, especially sandy and sandy loam soils, are the poorest in nitrogen, while chernozems are the richest.
95 % dry mass of plant tissues consists of four elements - DREAM,N, called organogens .
5 % falls on ash substances - mineral elements, the content of which is usually determined in tissues after burning organic matter of plants.
The ash content depends on the type and organ of the plant and growing conditions. IN seeds The ash content is on average 3 % , V roots and stems -4…5 , V leaves –5…15 % . The least amount of ash is in dead wood cells (about 1%). As a rule, the richer the soil and the drier the climate, the higher the content of ash elements in plants.
Plants are capable of absorbing almost all elements of D. I. Mendeleev’s periodic table from the environment. Moreover, many elements accumulate in plants in significant quantities and are included in the natural cycle of substances. However, for the normal functioning of the plant organism itself required only a small group of elements callednutritious .
Nutrients are called substances necessary for the life of an organism.
The element is considerednecessary , if its absenceprevents the plant from completing its life cycle ; element deficiencycauses specific disorders vital functions of the plant that are prevented or eliminated by the addition of this element; elementdirectly participates in the processes of transformation of substances and energy , and does not act on the plant indirectly.
Necessity of elementscan only be installed when growing plants on artificial nutrient media - in water and sand cultures. To do this, use distilled water or chemically pure quartz sand, chemically pure salts, chemically resistant vessels and utensils for preparing and storing solutions.
The most precise vegetation experiments have established that the elements necessary for higher plants include 19 elements: WITH ( 45 %), N(6.5%) and ABOUT 2 (42%) (digested during aerial feeding) + 7 (N, P, K, S, Ca, Mg, Fe) + Mn, Cu, Zn, Mo, B, Cl, Na, Si, Co.
All elements, depending on their content in plants, are divided into 3 groups: macroelements, microelements and ultramicroelements.
Macronutrients are contained in quantities from whole to tenths and hundredths of a percent: N, R,S, K, Sa,Mg; microelements - from thousandths to 100 thousandths of a percent: Fe, Mn, WITHu, Zn, V, Mo.
Co necessary b both for symbiotic fixation N , Na absorbed in relatively high quantities beets and is necessary for plants adapted to saline soils) , Si found in large quantities in straw cereals and is necessary for rice,Cl mosses, horsetails, and ferns accumulate.
Macroelements, their digestible compounds, role and functional disorders in case of deficiency in the plant
The value of an element is determined by the role it performs independently or as part of other organic compounds. High content does not always indicate the need for one or another element.
Nitrogen(near 1,5 % SM) is part of proteins, nucleic acids, lipid components of membranes, photosynthetic pigments, vitamins, etc. other vital connections.
Main digestible formsN are ions nitrate (NO 3- ) And ammonium (N.H. 4+ ) . Higher plants are also capable of assimilating nitrites and water soluble N-containing organic compounds ( amino acids, amides, polypeptides, etc..). Under natural conditions, these compounds are rarely a source of nutrition, since their content in the soil is usually very small.
Lack of N slows down height plants. Simultaneously root branching decreases, But ratio mass of roots and above-ground system can increase. It leads to reducing the area of the photosynthetic apparatus and shortening the period of vegetative growth (early ripening), which reduces photosynthetic potential and crop productivity.
N deficiency also causes serious violations energy metabolism(light energy is used worse, since the intensity of photosynthesis decreases, light saturation occurs earlier, and the compensation point is at a higher light intensity, breathing intensity may increase, But the coupling of oxidation with phosphorylation decreases), increase energy costs for maintaining the structure of the cytoplasm).
Nth fasting affects water regime(reduces the water-holding capacity of plant tissues, as it reduces the amount of colloid-bound water, the possibility of extrastomatal regulation is reduced transpiration and water yield increases). Therefore, a low level of N nutrition not only reduces the yield, but also reduces water use efficiency sowing.
External signs of starvation : Pale green, yellow leaf color, orange, red tones, drying out, necrosis, stunting and weak tillering, signs appearxeromorphism (small leaves).
Phosphorus (0,2-1,2 % CM). P is absorbed and functions in the plant only in oxidized form - in the form of orthophosphoric acid residues (PO 4 3-).
P- an obligatory component of such important compounds as NA, phosphoproteins, phospholipids, P- nal sugar esters, nucleotides involved in energy metabolism (ATP, NAD, FAD, etc.), vitamins.
P- The exchange is reduced to phosphorylation and transphosphorylation. Phosphorylation - this is the addition of the remainder P- nic acid to any organic compound to form an ester bond, for example phosphorylation of glucose, fructose-6-phosphate in glycolysis. Transphosphorylation is a process in which the remainder P- noic acid transferred from one organic substance to another. The value of the resulting P- organic compounds are huge.
P deficiency causes serious disorders of synthetic processes, functioning membranes, energy exchange.
External signs of starvation : blue-green color with a purple or bronze tint (delayed protein synthesis and accumulation of sugars), small narrow leaves,the root system turns brown , weakly developing, roothairs die . Plant growth stops , maturation is delayed fruits
Sulfur (0,2-1,0 % CM). It enters the plant in oxidized form, in the form of the SO 4 2- anion. In organic compounds S It is included only in a reduced form - as part of sulfhydryl groups (-SH) and disulfide bonds (-S-S-). Sulfate reduction occurs predominantly in the leaves. Restored S can again transform into an oxidized, functionally inactive form. In young leaves, S is mainly found in organic compounds, and in old leaves it accumulates in vacuoles in the form of sulfate.
S is a component of the most important biological compounds - coenzyme A And vitamins(thiamine, lipoic acid, biotin), which play an important role in respiration and lipid metabolism.
Coenzyme A (S forms a high-energy bond) supplies acetyl residue (CH 3 CO-S- KoA) in the Krebs cycle or for the biosynthesis of fatty acids, succinyl residue for the biosynthesis of porphyrins. Lipoic acid and thiamine are part of lipothiamine diphosphate (LTDP), which is involved inoxidative decarboxylation PVK and -ketoglutaric.
Many plant species contain small amounts volatile compounds S (sulfoxides are part of phytoncides onions and garlic). Representatives of the Cruciferous family synthesize sulfur-containing mustard oils.
S takes an active part in numerous metabolic reactions. Almost all squirrels contain sulfur-containing amino acids - methionine, cysteine, cystine. Functions S in proteins:
participation of HS groups and -S-S bonds in stabilizing the three-dimensional structure of proteins and
formation of bonds with coenzymes and prosthetic groups.
The combination of the methyl and HS groups determines the widespread participation of methionine in the formation of AC enzymes.
The synthesis of all polypeptide chains begins with this amino acid.
Another important function S in a plant organism, based on the reversible transition 2(-SH) = -HS-SH- consists of maintaining a certain level of redox potential in a cage. The sulfur-containing redox systems of the cell include the system cysteine = cystine and the glutathione system (is a tripeptide - consists of glutamine, cystine or cysteine and glycine). Its redox transformations are associated with the transition of -S-S groups of cystine to HS groups of cysteine.
S deficiency inhibits protein synthesis, reduces photosynthesis and plant growth rate, especially above ground parts.
External signs of starvation : whitening, yellowing of leaves (young).
Potassium(near 1 % CM). In plant tissues it is much more abundant than other cations. Content K in plants in 100-1000 times superior to him level in the external environment. K also enters the plant in the form of the K + cation.
K not included in any organic compound. In cells it is present mainly in ionic form and easily mobile. In greatest quantity K focused in young growing tissues, characterized high level of exchange substances.
Functions :
participation in regulation cytoplasmic viscosity, V increasing the hydration of its colloids And water holding capacity,
serves as the main counterion to neutralize negative charges inorganic and organic anions,
creates ionic asymmetry and electrical potential difference on the membrane, i.e. provides generation biocurrents in the plant
is activator of many enzymes, it is necessary for the incorporation of phosphate into organic compounds, the synthesis of proteins, polysaccharides and riboflavin, a component of flavin dehydrogenases. K especially necessary for young people, actively growing organs and tissues.
takes an active part in osmoregulation, (opening and closing stomata).
activates carbohydrate transport in the plant. It has been established that high levels of sugar in ripe grapes correlate with the accumulation of significant amountsK and organic acids in the juice of unripe berries and with subsequent releaseK when ripe. Influenced K starch accumulation increases in tubers potatoes, sucrose in the sugar industry beets, monosaccharides V fruits and vegetables, cellulose, hemicelluloses and pectin substances in cellular walls plants.
As a result increased resistance of cereals to lodging, fungal and bacterial diseases .
With K deficiency is decreasing functioning of the cambium, are violated processes of cell division and elongation, development of vascular tissues, the thickness of the cell wall and epidermis decreases. As a result of shortening the internodes, rosette forms of plants. Decreasing photosynthetic productivity (by reducing the outflow of assimilates from leaves).
Calcium (0,2 % CM). Enters the plant in the form of Ca 2+ ion. Accumulates in old organs and fabrics. When the physiological activity of cells decreases, Ca moves from the cytoplasm to the vacuole and is deposited in the form of insoluble compounds oxalic, lemon, etc. acids This significantly reduces mobility Ca in the plant.
A large number of Ca associated with pectic substances of the cell wall and the median plate.
The role of Ca ions :
membrane structure stabilization, regulation of ion flows and participation in bioelectric phenomena. Ca contains a lot in mitochondria, chloroplasts and nuclei, as well as in complexes with biopolymers of cell boundary membranes.
participation in cation exchange processes in the root(along with the hydrogen proton, it accepts active participation in the primary mechanisms of ion entry into root cells).
helps eliminate the toxicity of excess ion concentrationsN.H. 4+ , Al , Mn , Fe , increases resistance to salinity,(limit the entry of other ions),
reduces soil acidity.
participation in processes movement cytoplasm (structural rearrangement of actomyosin-like proteins), reversible changes in its viscosity,
defines spatial organization of cytoplasmic enzyme systems(for example, glycolytic enzymes),
activation of a number of enzymes ( dehydrogenases, amylases, phosphatases, kinases, lipases)- determines the quaternary structure of the protein, participates in the creation of bridges in enzyme-substrate complexes, affects the state of allosteric centers).
determines the structure of the cytoskeleton - regulates processes assembly-disassembly of microtubules, secretion of cell wall components with the participation of Golgi vesicles.
Protein complex with Ca activates many enzyme systems: protein kinases, Ca-ATP transportase, actomyosin ATPase.
The regulatory effect of Ca on many aspects of metabolism is associated with the functioning of a specific protein - calmodulin . This is an acidic (IET 3.0-4.3) thermostable low molecular weight protein. With the participation of calmodulin intracellular concentration is regulatedCa . The Ca-calmodulin complex controls assembly spindle microtubules, formation of the cell cytoskeleton and cell wall formation.
With a lack of Ca (on acidic, saline soils and peat bogs) primarily meristematic tissues suffer And root system. In dividing cells cell walls are not formed, as a result there arise multinucleate cells. The formation of lateral roots and root hairs stops. Flaw Ca also causes swelling of pectin substances, that leads to sliming of cell walls and rotting plant tissues.
External signs of starvation : roots, leaves, sections of the stem rot and die, the tips and edges of the leaves first turn white, then turn black, bend and curl.
Magnesium(near 0,2 % CM). Especially a lot of Mg in young growing parts of the plant, as well as in generative organs and stockpiling tissues.
Enters the plant in the form of Mg 2+ ion and, unlike Ca, has comparatively high mobility. The easy mobility of Mg 2+ is explained by the fact that almost 70 % this cation is associated in plants with anions of organic and inorganic acids.
Role Mg :
included part chlorophyll(near 10-12 % Mg),
is an activator of a number of enzyme systems (RDP carboxylase, phosphokinases, ATPases, enolases, Krebs cycle enzymes, pentose phosphate pathway, alcoholic and lactic acid fermentation), DNA and RNA polymerases.
activates electron transport processes during photophosphorylation.
necessary for the formation of ribosomes and polysomes, for the activation of amino acids and protein synthesis.
participates in the formation of a certain spatial structure of the NK.
enhances the synthesis of essential oils and rubbers.
prevents oxidation by ascorbic acid (forming a complex compound with it).
Flaw Mg leads to violationP- nogo, protein And carbohydrate exchanges. With magnesium starvation, the formation of plastid: the grains stick together, the lamellae of the stapes are torn.
External signs of starvation : the leaves along the edges are yellow, orange, red (marbled). Subsequently chlorosis and necrosis develop leaves. Leaf striping in cereals is characteristic (chlorosis between the veins, which remain green).
Iron (0,08 %) . Enters the plant in the form of Fe 3+.
Iron is included in ETC photosynthetic and oxidative phosphorylation(cytochromes, ferredoxin), is component of a number of oxidases(cytochrome oxidases, catalase, peroxidases). In addition, iron is an integral part enzymes that catalyze the synthesis of chlorophyll precursors(aminolevulinic acid and protoporphyrins).
Plants may include Fe into reserve substances. For example, plastids contain the protein ferritin, which has iron (up to 23% SM) in a non-heme form.
Role of Fe associated with his ability to reversible redox transformations(Fe 3+ - Fe 2+) and participation in electron transport.
That's why Fe deficiency causes deep chlorosis in developing leaves (may be completely white), and slows down the most important processes of energy exchange - photosynthesis and respiration.
Silicon() is found mainly in cell walls.
His flaw can retard the growth of cereals (corn, oats, barley) and dicotyledons (cucumbers, tomatoes, tobacco). Deficiency during the reproductive period causes a decrease in the number of seeds. With a lack of Si, the ultrastructure of cellular organelles is disrupted.
Aluminum() is especially important for hydrophytes; it is accumulated by ferns and tea.
Flaw causes chlorosis.
Excess toxic (binds P and leads to P- nomu fasting).
To learn how to determine which nutrient your plants are lacking, read the article.
Nitrogen
Part of proteins, enzymes, nucleic acids, chlorophyll, vitamins, alkaloids. The level of nitrogen nutrition determines the intensity of the synthesis of protein and other nitrogenous organic compounds in plants and, consequently, growth processes. Lack of nitrogen has a particularly dramatic effect on the growth of vegetative organs.
Nitrogen deficiency in plants can be found in all types of soils. This is especially evident in early spring, when, due to low soil temperatures, the processes of mineralization and nitrate formation are weak. Most often, nitrogen deficiency is observed on sandy, sandy loam and loamy soddy-podzolic soils, red soils and gray soils.
Signs of nitrogen deficiency appear very clearly at different stages of development. The general and main signs of nitrogen deficiency in plants are: depressed growth, short and thin shoots and stems, small inflorescences, weak foliage of plants, weak branching and weak tillering (in cereals), small, narrow leaves, their color is pale green, chlorotic. Changes in leaf color can be caused by other reasons besides nitrogen deficiency. Yellowing of the lower leaves occurs with a lack of moisture in the soil, as well as with the natural aging and death of leaves. With a lack of nitrogen, lightening and yellowing of the color begins with the veins and the adjacent part of the leaf blade; parts of the leaf removed from the veins may still retain a light green color. As a rule, there are no green veins on a leaf that has turned yellow from a lack of nitrogen. When leaves age, their yellowing begins from the part of the leaf blade located between the veins, and the veins and tissues around them still retain a green color.
In some plants (potatoes, beets), when potassium fertilizers are applied, especially low-percentage ones (sylvinite, potassium salt), a general lightening of the leaves is observed. But in this case, there may not be a suspension of plant growth, a decrease in the formation of new shoots, thinning of the stems and a reduction in the size of young leaves, as with a lack of nitrogen. With a lack of nitrogen, the lightening of color begins with the older, lower leaves, which acquire yellow, orange and red shades. This coloring extends further to younger leaves and can also appear on leaf petioles. With a lack of nitrogen, leaves fall prematurely, and plant maturation accelerates.
Nitrogen starvation of plants most often occurs on acidic soils and in places where total sodding of the area is used. Nitrogen fertilizers are not applied to crops in the second half of the growing season; they are used mainly in the spring.
Phosphorus
Plays an extremely important role in energy exchange processes in plant organisms. The energy of sunlight during the process of photosynthesis and the energy released during the oxidation of previously synthesized organic compounds during respiration is accumulated in plants in the form of energy from phosphate bonds in the so-called high-energy compounds, the most important of which is adenosine triphosphoric acid (ATP). The energy accumulated in ATP is used for all life processes of plant growth and development, absorption of nutrients from the soil, synthesis of organic compounds, and their transport. With a lack of phosphorus, the metabolism of energy and substances in plants is disrupted.
Phosphorus deficiency has a particularly dramatic effect on the formation of reproductive organs in all plants. Its deficiency inhibits development and delays ripening, causing a decrease in yield and deterioration in product quality.
Phosphorus deficiency in plants can occur on all soils, but most often occurs on acidic soils, rich in mobile forms of aluminum and iron, soddy-podzolic and red soils. Phosphorus deficiency is more difficult to determine by the appearance of plants than nitrogen deficiency. With a lack of phosphorus, a number of the same symptoms are observed as with a lack of nitrogen - suppressed growth (especially in young plants), short and thin shoots, small, prematurely falling leaves. However, there are also significant differences - with a lack of phosphorus, the color of the leaves is dark green, bluish, dull. With a severe lack of phosphorus, the color of leaves, leaf petioles and ears appears purple, and in some plants, violet shades. When leaf tissues die, dark, sometimes black spots appear. Drying leaves have a dark, almost black color, and when there is a lack of nitrogen, they are light. Signs of phosphorus deficiency appear first on older, lower leaves. A characteristic sign of phosphorus deficiency is also a delay in flowering and ripening.
Phosphorus coming from mineral fertilizers, such as superphosphate, is almost completely fixed in the places of application, so it must be applied precisely to the root horizon, ideally as deep as possible, where soil moisture is constantly present. Also, before applying phosphorus fertilizers, the soil must be watered . In order for phosphorus to be more fully absorbed by plants, acidic soils must be deoxidized (limed) and organic matter added to them.
Potassium
Participates in the processes of synthesis and outflow of carbohydrates in plants, determines the water-holding capacity of cells and tissues, affects the resistance of plants to unfavorable environmental conditions and the susceptibility of crops to diseases.
Potassium deficiency is most often observed on peaty, floodplain, sandy and sandy loam soils. Signs of deficiency are usually noticeable in the middle of the growing season, during a period of strong plant growth. With a lack of potassium, the color of the leaves is bluish-green, dull, often with a bronze tint. There is yellowing, and subsequently browning and dying of the tips and edges of the leaves (marginal “burn” of the leaves). Brown spotting develops especially closer to the edges. The edges of the leaves curl and wrinkles are observed. The veins appear to be embedded in the leaf tissue. Signs of deficiency in most plants appear first on the older lower leaves. The stem is thin, loose, lodging. Potassium deficiency usually causes retardation of growth, as well as the development of buds or rudimentary inflorescences.
Potassium, like phosphorus, during root feeding must be applied deep into the layer of the plant root system.
Calcium
Plays an important role in photosynthesis and the movement of carbohydrates, in the processes of nitrogen absorption by plants. It participates in the formation of cell membranes, determines water content and maintains the structure of cellular organelles.
A calcium deficiency is observed on sandy and sandy loamy acidic soils, especially when high doses of potassium fertilizers are applied, as well as on solonetzes. Signs of deficiency appear primarily on young leaves. The leaves are chlorotic, curved, and their edges curl upward. The edges of the leaves are irregular in shape and may show brown scorching. Damage and death of apical buds and roots, and severe branching of the roots are observed. In acidic soils with a lack of calcium, plants may develop associated symptoms caused by manganese toxicity.
Magnesium
It is part of chlorophyll, participates in the movement of phosphorus in plants and carbohydrate metabolism, and affects the activity of redox processes. Magnesium is also part of the main phosphorus-containing reserve organic compound - phytin.
Sandy and sandy loam sod-podzolic soils are poor in magnesium. With a lack of magnesium, a characteristic form of chlorosis is observed - at the edges of the leaf and between the veins, the green color changes to yellow, red, and purple. Spots of different colors subsequently appear between the veins due to tissue death. At the same time, large veins and adjacent areas of the leaf remain green. The leaf tips and edges curl, causing the leaves to become domed, the edges of the leaves to wrinkle and gradually die. Signs of deficiency appear and spread from the lower leaves to the upper ones.
Sulfur
It is important in plant life. The main amount of it in plants is found in proteins (sulfur is part of the amino acids cysteine, cystine and methionine) and other organic compounds - enzymes, vitamins, mustard and garlic oils. Sulfur takes part in the nitrogen and carbohydrate metabolism of plants and the respiration process, the synthesis of fats. Plants from the legume and cruciferous families, as well as potatoes, contain more sulfur.
A lack of sulfur is manifested in slow growth of stems in thickness, in a pale green color of leaves without tissue death. Signs of sulfur deficiency are similar to signs of nitrogen deficiency; they appear primarily on young plants; in legumes, weak formation of nodules on the roots is observed.
Any plant is a real living organism, and in order for its development to proceed fully, vital conditions are required: light, air, moisture and nutrition.
All of them are equivalent and the lack of one has a detrimental effect on the overall condition. In this article we will talk about such an important component in the life of plants as mineral nutrition.
Features of the nutrition process
Being the main source of energy, without which all life processes die out, food is necessary for every body. Consequently, nutrition is not just important, but one of the main conditions for the high-quality growth of a plant, and they obtain food by using all above-ground parts and the root system. Through their roots, they extract water and the necessary mineral salts from the soil, replenishing the necessary supply of substances, providing soil or mineral nutrition to plants.
A significant role in this process is assigned to root hairs, so this kind of nutrition has another name - root. With the help of these thread-like hairs, the plant draws aqueous solutions of a wide variety of chemical elements from the ground.
They work on the principle of a pump and are located on the root in the suction zone. Salt solutions entering the hair tissue move into conducting cells - tracheids and vessels. Through them, substances enter the wires and then spread along the stems to all above-ground parts.
Elements of mineral nutrition for plants
So, food for representatives of the plant kingdom are substances obtained from the soil. Mineral or soil nutrition of plants is the unity of different processes: from absorption and promotion to the assimilation of elements found in the soil in the form of mineral salts.
Studies of ash left over from plants have shown how many chemical elements remain in it and their quantity in different parts and different representatives of the flora is not the same. This is evidence that chemical elements are absorbed and accumulated in plants. Such experiments led to the following conclusions: the elements found in all plants are considered vital - phosphorus, calcium, potassium, sulfur, iron, magnesium, as well as microelements represented by zinc, copper, boron, manganese, etc.
Despite the different amounts of these substances, they are present in any plant, and replacing one element with another is impossible under any circumstances. The level of presence of minerals in the soil is very important, since the productivity of agricultural crops and the decorativeness of flowering plants depend on it. In different soils, the degree of saturation of the soil with the necessary substances is also different. For example, in the temperate latitudes of Russia there is a significant shortage of nitrogen and phosphorus, and sometimes potassium, so the application of fertilizers - nitrogen and potassium-phosphorus - is mandatory. Each element has its own role in the life of the plant organism.
Proper plant nutrition (mineral) stimulates quality development, which occurs only when all the necessary substances are present in the required quantities in the soil. If there is a shortage or excess of some of them, plants react by changing the color of the foliage. Therefore, one of the important conditions for agricultural technology of agricultural crops is the developed standards for applying fertilizing and fertilizers. Note that it is better to underfeed many plants than to overfeed them. For example, for all berry garden crops and their wild forms, it is excess nutrition that is destructive. Let's find out how different substances interact with and what each of them affects.
Nitrogen
One of the most essential elements for plant growth is nitrogen. It is present in proteins and amino acids. Nitrogen deficiency manifests itself in changes in leaf color: at first, the leaf becomes smaller and turns red. A significant deficiency causes an unhealthy yellow-green color or bronze-red coating. The older leaves on the bottom of the shoots are affected first, then along the entire stem. With continued deficiency, branch growth and fruit set stop.
Excessive compounds lead to increased nitrogen content in the soil. At the same time, rapid growth of shoots and intensive growth of green mass are observed, which does not allow the plant to lay flower buds. As a result, the productivity of the plant is noticeably reduced. This is why balanced mineral soil nutrition of plants is so important.
Phosphorus
This element is no less important in plant life. It is a constituent part of nucleic acids, the combination of which with proteins forms nucleoproteins that are part of the cell nucleus. Phosphorus is concentrated in plant tissues, flowers and seeds. In many ways, the ability of trees to withstand natural disasters depends on the availability of phosphorus. It is responsible for frost resistance and comfortable wintering. Deficiency of the element manifests itself in a slowdown in cell division, cessation of plant growth and development of the root system, the foliage acquires a purple-red hue. Worsening the situation threatens the plant with death.
Potassium
Plant nutritional minerals include potassium. It is needed in the greatest quantities, since it stimulates the process of absorption, biosynthesis and transportation of vital elements to all parts of the plant.
Normal supply of potassium increases the resistance of the plant organism, stimulates defense mechanisms, drought and cold resistance. Flowering and fruit formation with sufficient potassium supply are more efficient: flowers and fruits are much larger and brighter in color.
If there is a deficiency of the element, growth slows down significantly, and severe deficiency leads to thinning and fragility of the stems, and a change in the color of the leaves to lilac-bronze. The leaves then dry out and collapse.
Calcium
Normal soil nutrition of plants (mineral) is impossible without calcium, which is present in almost all cells of the plant body, stabilizing their functionality. This element is especially significant for the quality growth and functioning of the root system. Calcium deficiency is accompanied by delayed root growth and ineffective formation of the root system. A lack of calcium manifests itself in the redness of the edges of the upper leaves on young shoots. Increasing deficiency will add purple coloration throughout the entire leaf area. If calcium never reaches the plant, then the leaves of the current year’s shoots dry out along with the tops.
Magnesium
The process of mineral nutrition of plants during normal development is impossible without magnesium. Being part of chlorophyll, it is an essential element of the photosynthesis process.
By activating enzymes involved in metabolism, magnesium stimulates the formation of growth buds, seed germination and other reproductive activities.
Signs of magnesium deficiency are the appearance of a reddish tint at the base of the leaves, spreading along the central conductor and occupying up to two-thirds of the leaf blade. Severe magnesium deficiency leads to leaf necrosis, reduced plant productivity and its decorative properties.
Iron
Responsible for normal plant respiration, this element is indispensable in redox processes, since it is the acceptor of oxygen molecules and synthesizes chlorophyll precursor substances. When iron deficiency occurs, the plant becomes lighter and thinner, acquiring a yellowish-green and then bright yellow color with dark rusty spots. Impaired breathing provokes a slowdown in plant growth and a significant reduction in yield.
Manganese
Without exaggerating the importance of essential microelements, let us remember how plants and soil react to them. The mineral nutrition of plants is supplemented with manganese, which is essential for the productive course of photosynthesis processes, as well as protein synthesis, etc. A lack of manganese manifests itself in weak young growth, and a severe deficiency makes it unviable - the leaves on the stems turn yellow, the tops of the shoots dry out.
Zinc
This trace element is an active participant in the process of auxin formation and a catalyst for plant growth. Being an essential component of chloroplasts, zinc is present during the photochemical breakdown of water.
It is necessary for fertilization and development of the egg. Zinc deficiency becomes noticeable at the end and during rest - the leaves take on a lemon tint.
Copper
Mineral or root nutrition of plants will be incomplete without this microelement. Part of a number of enzymes, copper activates such important processes as plant respiration, protein and carbohydrate metabolism. Copper derivatives are essential components of photosynthesis. The deficiency of this element is manifested by drying of the apical shoots.
Bor
Stimulating the synthesis of amino acids, carbohydrates and proteins, boron is present in many enzymes that regulate metabolism. A sign of acute boron deficiency is the appearance of variegated spots on young stems and a bluish tint to the leaves at the base of the shoots. Further deficiency of the element leads to the destruction of foliage and the death of young growth. Flowering is weak and unproductive - fruits are not set.
We have listed the main chemical elements necessary for normal development, high-quality flowering and fruiting. All of them, properly balanced, constitute high-quality mineral nutrition for plants. And the importance of water is also difficult to overestimate, because all substances from the soil come in dissolved form.
The role of elements in plant life -
Nitrogen
Nitrogen is one of the main elements necessary for plants. It is part of all proteins (its content ranges from 15 to 19%), nucleic acids, amino acids, chlorophyll, enzymes, many vitamins, lipoids and other organic compounds formed in plants. The total nitrogen content in the plant is 0.2 - 5% or more of the air-dry matter mass.In the free state, nitrogen is an inert gas, of which the atmosphere contains 75.5% of its mass. However, nitrogen cannot be absorbed in elemental form by plants, with the exception of legumes, which use nitrogen compounds produced by nodule bacteria developing on their roots, which are capable of absorbing atmospheric nitrogen and converting it into a form accessible to higher plants.
Nitrogen is absorbed by plants only after combining it with other chemical elements in the form of ammonium and nitrates - the most accessible forms of nitrogen in the soil. Ammonium, being a reduced form of nitrogen, when absorbed by plants, is easily used in the synthesis of amino acids and proteins. The synthesis of amino acids and proteins from reduced forms of nitrogen occurs faster and with less energy than the synthesis from nitrates, for the reduction of which to ammonia the plant requires additional energy. However, the nitrate form of nitrogen is safer for plants than the ammonia form, since high concentrations of ammonia in plant tissues cause poisoning and death.
Ammonia accumulates in the plant when there is a lack of carbohydrates, which are necessary for the synthesis of amino acids and proteins. A deficiency of carbohydrates in plants is usually observed in the initial period of the growing season, when the assimilation surface of the leaves has not yet developed enough to satisfy the plants' need for carbohydrates. Therefore, ammonia nitrogen can be toxic to crops whose seeds are low in carbohydrates (sugar beets, etc.). As the assimilation surface and carbohydrate synthesis develop, the efficiency of ammonia nutrition increases, and plants assimilate ammonia better than nitrates. During the initial growth period, these crops must be provided with nitrogen in the nitrate form, while crops such as potatoes, whose tubers are rich in carbohydrates, can use nitrogen in the ammonia form.
With a lack of nitrogen, plant growth slows down, the intensity of tillering of cereals and flowering of fruit and berry crops is weakened, the growing season is shortened, the protein content decreases and the yield is reduced.
Phosphorus
Phosphorus is involved in metabolism, cell division, reproduction, transmission of hereditary properties and other complex processes occurring in the plant. It is part of complex proteins (nucleoproteins), nucleic acids, phosphatides, enzymes, vitamins, phytin and other biologically active substances. A significant amount of phosphorus is found in plants in mineral and organic forms. Mineral phosphorus compounds are found in the form of orthophosphoric acid, which is used by the plant primarily in the processes of converting carbohydrates. These processes affect the accumulation of sugar in sugar beets, starch in potato tubers, etc.The role of phosphorus, which is part of organic compounds, is especially important. A significant part of it is presented in the form of phytin - a typical reserve form of organic phosphorus. Most of this element is found in the reproductive organs and young plant tissues, where intensive synthesis processes take place. Experiments with labeled (radioactive) phosphorus revealed that there is several times more of it at the growing points of the plant than in the leaves.
Phosphorus can move from old plant organs to young ones. Phosphorus is especially necessary for young plants, as it promotes the development of the root system and increases the intensity of tillering of grain crops. It has been established that by increasing the content of soluble carbohydrates in cell sap, phosphorus increases the winter hardiness of winter crops.
Like nitrogen, phosphorus is one of the important elements of plant nutrition. At the very beginning of growth, the plant experiences an increased need for phosphorus, which is covered by the reserves of this element in the seeds. On soils poor in fertility, young plants, after consuming phosphorus from the seeds, show signs of phosphorus starvation. Therefore, on soils containing a small amount of mobile phosphorus, it is recommended to apply granular superphosphate in rows simultaneously with sowing.
Phosphorus, unlike nitrogen, accelerates the development of crops, stimulates the processes of fertilization, formation and ripening of fruits.
The main source of phosphorus for plants are salts of orthophosphoric acid, usually called phosphoric acid. Plant roots absorb phosphorus in the form of anions of this acid. The most accessible to plants are water-soluble monosubstituted salts of orthophosphoric acid: Ca (H 2 PO 4) 2 - H 2 O, KH 2 PO 4 NH 4 H 2 PO 4 NaH 2 PO 4, Mg (H 2 PO 4) 2.
Potassium
Potassium is not part of the organic compounds of plants. However, it plays a vital physiological role in the carbohydrate and protein metabolism of plants, activates the use of nitrogen in ammonia form, affects the physical state of cell colloids, increases the water-holding capacity of protoplasm, plant resistance to wilting and premature dehydration, and thereby increases plant resistance to short-term droughts.With a lack of potassium (despite a sufficient amount of carbohydrates and nitrogen), the movement of carbohydrates in plants is suppressed, the intensity of photosynthesis, nitrate reduction and protein synthesis decreases.
Potassium affects the formation of cell walls, increases the strength of cereal stems and their resistance to lodging.
The quality of the crop significantly depends on potassium. Its deficiency leads to shriveled seeds, decreased germination and vitality; plants are easily affected by fungal and bacterial diseases. Potassium improves the shape and taste of potatoes, increases the sugar content in sugar beets, affects not only the color and aroma of strawberries, apples, peaches, grapes, but also the juiciness of oranges, improves the quality of grain, tobacco leaves, vegetable crops, cotton fiber, flax , hemp. The greatest amount of potassium is required by plants during the period of their intensive growth.
Increased demand for potassium nutrition is observed in root crops, vegetables, sunflower, buckwheat, and tobacco.
Potassium in a plant is found predominantly in cell sap in the form of cations bound by organic acids and is easily washed out of plant residues. It is characterized by repeated use (recycling). It easily moves from old plant tissues, where it has already been used, to young ones.
A lack of potassium, as well as its excess, negatively affects the quantity of the crop and its quality.
Magnesium
Magnesium is part of chlorophyll and is directly involved in photosynthesis. Chlorophyll contains about 10% of the total amount of magnesium in the green parts of plants. Magnesium is also associated with the formation of pigments such as xanthophyll and carotene in leaves. Magnesium is also part of the reserve substance phytin, contained in plant seeds and pectin substances. About 70 - 75% of magnesium in plants is in mineral form, mainly in the form of ions.Magnesium ions are adsorptively associated with cell colloids and, along with other cations, maintain ionic balance in the plasma; like potassium ions, they help compact the plasma, reduce its swelling, and also participate as catalysts in a number of biochemical reactions occurring in the plant. Magnesium activates the activity of many enzymes involved in the formation and transformation of carbohydrates, proteins, organic acids, fats; affects the movement and transformation of phosphorus compounds, fruit formation and seed quality; accelerates the ripening of grain seeds; helps improve the quality of the crop, the content of fat and carbohydrates in plants, and the frost resistance of citrus fruits, fruit and winter crops.
The highest magnesium content in the vegetative organs of plants is observed during the flowering period. After flowering, the amount of chlorophyll in the plant sharply decreases, and magnesium flows from the leaves and stems into the seeds, where phytin and magnesium phosphate are formed. Consequently, magnesium, like potassium, can move in a plant from one organ to another.
With high yields, agricultural crops consume up to 80 kg of magnesium per 1 ha. Potatoes, fodder and sugar beets, tobacco, and legumes absorb the largest amounts of it.
The most important form for plant nutrition is exchangeable magnesium, which, depending on the type of soil, accounts for 5 - 10% of the total content of this element in the soil.
Calcium
Calcium is involved in the carbohydrate and protein metabolism of plants, the formation and growth of chloroplasts. Like magnesium and other cations, calcium maintains a certain physiological balance of ions in the cell, neutralizes organic acids, and affects the viscosity and permeability of protoplasm. Calcium is necessary for the normal nutrition of plants with ammonia nitrogen; it makes it difficult to reduce nitrates to ammonia in plants. The construction of normal cell membranes largely depends on calcium.Unlike nitrogen, phosphorus and potassium, which are usually found in young tissues, calcium is found in significant quantities in old tissues; Moreover, there is more of it in leaves and stems than in seeds. Thus, in pea seeds calcium makes up 0.9% of the air-dry matter, and in straw - 1.82%
Perennial leguminous grasses consume the greatest amount of calcium - about 120 kg of CaO per 1 ha.
Lack of calcium in field conditions is observed on very acidic, especially sandy, soils and solonetzes, where the supply of calcium to plants is inhibited by hydrogen ions on acidic soils and sodium on solonetzes.
Sulfur
Sulfur is part of the amino acids cystine and methionine, as well as glutathione, a substance found in all plant cells and plays a role in metabolism and redox processes, as it is a carrier of hydrogen. Sulfur is an essential component of some oils (mustard, garlic) and vitamins (thiamine, biotin), it affects the formation of chlorophyll, promotes the enhanced development of plant roots and nodule bacteria that absorb atmospheric nitrogen and live in symbiosis with legumes. Some sulfur is found in plants in inorganic oxidized form.On average, plants contain about 0.2 - 0.4% sulfur from dry matter, or about 10% in ash. Crops from the cruciferous family (cabbage, mustard, etc.) absorb the most sulfur. Agricultural crops consume the following amount of sulfur (kgha): grains and potatoes - 10 - 15, sugar beets and legumes - 20 - 30, cabbage - 40 - 70.
Sulfur starvation is most often observed on sandy loam and sandy soils of the non-chernozem zone, which are poor in organic matter.
Iron
Iron is consumed by plants in significantly smaller quantities (1 - 10 kg per 1 ha) than other macroelements. It is part of the enzymes involved in the creation of chlorophyll, although this element is not included in it. Iron is involved in redox processes occurring in plants, since it is able to pass from the oxidized form to the ferrous form and back. In addition, without iron, the process of plant respiration is impossible, since it is an integral part of respiratory enzymes.Lack of iron leads to the breakdown of growth substances (auxins) synthesized by plants. The leaves become light yellow. Iron cannot, like potassium and magnesium, move from old tissues to young ones (i.e., be reused by the plant).
Iron starvation most often occurs on carbonate and heavily limed soils. Fruit crops and grapes are especially sensitive to iron deficiency. With prolonged iron starvation, the apical shoots die off.
Bor
Boron is found in plants in negligible quantities: 1 mg per 1 kg of dry matter. Various plants consume from 20 to 270 g of boron per 1 ha. The lowest boron content is observed in cereal crops. Despite this, boron has a great influence on the synthesis of carbohydrates, their transformation and movement in plants, the formation of reproductive organs, fertilization, root growth, redox processes, protein and nucleic acid metabolism, and the synthesis and movement of growth stimulants. The presence of boron is also associated with the activity of enzymes, osmotic processes and hydration of plasma colloids, drought and salt tolerance of plants, and the content of vitamins in plants - ascorbic acid, thiamine, riboflavin. Plant uptake of boron increases the uptake of other nutrients. This element is not able to move from old plant tissues to young ones.With a lack of boron, plant growth slows down, the growth points of shoots and roots die off, buds do not open, flowers fall off, cells in young tissues disintegrate, cracks appear, plant organs turn black and take on an irregular shape.
Boron deficiency most often occurs on soils with a neutral and alkaline reaction, as well as on limed soils, since calcium interferes with the entry of boron into the plant.
Molybdenum
Molybdenum is absorbed by plants in smaller quantities than other trace elements. There are 0.1 - 1.3 mg of molybdenum per 1 kg of plant dry matter. The largest amount of this element is contained in the seeds of legumes - up to 18 mg per 1 kg of dry matter. From 1 hectare of plants, 12 - 25 g of molybdenum is harvested.In plants, molybdenum is part of the enzymes involved in the reduction of nitrates to ammonia. With a lack of molybdenum, nitrates accumulate in plants and nitrogen metabolism is disrupted. Molybdenum improves calcium nutrition of plants. Due to the ability to change valency (by giving away an electron, it becomes hexavalent, and by adding it - pentavalent), molybdenum participates in the redox processes occurring in the plant, as well as in the formation of chlorophyll and vitamins, in the exchange of phosphorus compounds and carbohydrates. Molybdenum is of great importance in the fixation of molecular nitrogen by nodule bacteria.
If there is a lack of molybdenum, plants are stunted in growth and yields are reduced, the leaves become pale in color (chlorosis), and as a result of disturbances in nitrogen metabolism they lose turgor.
Molybdenum starvation is most often observed on acidic soils with a pH less than 5.2. Liming increases the mobility of molybdenum in the soil and its consumption by plants. Legumes are especially sensitive to the lack of this element in the soil. Under the influence of molybdenum fertilizers, not only does the yield increase, but also the quality of products improves - the content of sugar and vitamins in vegetable crops, protein in leguminous crops, protein in legume hay, etc. increases.
An excess of molybdenum, as well as its deficiency, has a negative effect on plants - the leaves lose their green color, growth is delayed and plant yield is reduced.
Copper
Copper, like other trace elements, is consumed by plants in very small quantities. There are 2 - 12 mg of copper per 1 kg of plant dry weight.Copper plays an important role in redox processes, having the ability to transform from monovalent to divalent forms and back. It is a component of a number of oxidative enzymes, increases the intensity of respiration, and affects the carbohydrate and protein metabolism of plants. Under the influence of copper, the chlorophyll content in the plant increases, the process of photosynthesis intensifies, and plant resistance to fungal and bacterial diseases increases.
Insufficient supply of plants with copper negatively affects the water-holding and water-absorbing capacity of plants. Most often, copper deficiency is observed in peat-bog soils and some soils of light mechanical composition.
At the same time, too high a content of copper available to plants in the soil, as well as other microelements, negatively affects the yield, since the development of roots is disrupted and the supply of iron and manganese to the plant is reduced.
Manganese
Manganese, like copper, plays an important role in the redox reactions occurring in the plant; it is part of the enzymes with the help of which these processes occur. Manganese is involved in the processes of photosynthesis, respiration, carbohydrate and protein metabolism. It accelerates the flow of carbohydrates from the leaves to the root.In addition, manganese is involved in the synthesis of vitamin C and other vitamins; it increases the sugar content in the roots of sugar beets and proteins in grain crops.
Manganese starvation is most often observed on carbonate, peat and heavily limed soils.
With a deficiency of this element, the development of the root system and plant growth slows down, and productivity decreases. Animals that eat food low in manganese suffer from weakened tendons and poor bone development. In turn, excess amounts of soluble manganese, observed in highly acidic soils, can have a negative effect on plants. The toxic effect of excess manganese is eliminated by liming.
Zinc
Zinc is part of a number of enzymes, for example, carbonic anhydrase, which catalyzes the breakdown of carbonic acid into water and carbon dioxide. This element takes part in the redox processes occurring in the plant, in the metabolism of carbohydrates, lipids, phosphorus and sulfur, in the synthesis of amino acids and chlorophyll. The role of zinc in redox reactions is less than the role of iron and manganese, since it does not have a variable valence. Zinc affects the processes of plant fertilization and embryo development.Insufficient provision of plants with assimilable zinc is observed on gravel, sandy, sandy loam and carbonate soils. Vineyards, citrus fruits and fruit trees in dry areas of the country on alkaline soils are especially affected by zinc deficiency. With prolonged zinc starvation, fruit trees experience dry tops - the death of the upper branches. Of the field crops, the most acute need for this element is corn, cotton, soybeans and beans.
The disruption of chlorophyll synthesis caused by a lack of zinc leads to the appearance of chlorotic spots of light green, yellow and even almost white on the leaves.
Cobalt
In addition to all the microelements described above, plants also contain microelements whose role in plants has not been sufficiently studied (for example, cobalt, iodine, etc.). At the same time, it has been established that they are of great importance in the life of humans and animals.Thus, cobalt is part of vitamin B12, the deficiency of which disrupts metabolic processes, in particular, the synthesis of proteins, hemoglobin, etc. is weakened.
Insufficient supply of feed with cobalt, with a content of less than 0.07 mg per 1 kg of dry weight, leads to a significant decrease in animal productivity, and with a sharp lack of cobalt, livestock develops tabes.
Iodine
Iodine is a component of the thyroid hormone - thyroxine. With a lack of iodine, livestock productivity sharply decreases, the functions of the thyroid gland are disrupted, and its enlargement occurs (goiter appears). The lowest iodine content is observed in podzolic and gray forest soils; Chernozems and gray soils are better supplied with iodine. In soils of light mechanical composition, poor in colloidal particles, there is less iodine than in clayey soils.Chemical analysis shows that plants also contain elements such as sodium, silicon, chlorine, and aluminum.
Sodium
Sodium makes up 0.001 to 4% of the dry mass of plants. Of the field crops, the highest content of this element is observed in sugar, table and fodder beets, turnips, fodder carrots, alfalfa, cabbage, and chicory. With the sugar beet harvest, about 170 kg of sodium per 1 hectare is removed, and about 300 kg of fodder.Silicon
Silicon is found in all plants. The largest amount of silicon is found in cereal crops. The role of silicon in plant life has not been established. It increases the uptake of phosphorus by plants by increasing the solubility of soil phosphates under the action of silicic acid. Of all the ash elements, the soil contains the most silicon, and plants do not lack it.Chlorine
Chlorine is found in plants in larger quantities than phosphorus and sulfur. However, its necessity for normal plant growth has not been established. Chlorine quickly enters plants, negatively affecting a number of physiological processes. Chlorine reduces the quality of the crop and makes it difficult for the plant to receive anions, in particular phosphate.Citrus crops, tobacco, grapes, potatoes, buckwheat, lupine, seradella, flax, and currants are very sensitive to high chlorine content in the soil. Cereals and vegetables, beets, and herbs are less sensitive to large amounts of chlorine in the soil.
Aluminum
Aluminum can be contained in significant quantities in plants: its share in the ash of some plants accounts for up to 70%. Aluminum disrupts the metabolism in plants, complicates the synthesis of sugars, proteins, phosphatides, nucleoproteins and other substances, which negatively affects plant productivity. The most sensitive crops to the presence of mobile aluminum in the soil (1 - 2 mg per 100 g of soil) are sugar beets, alfalfa, red clover, winter and spring vetch, winter wheat, barley, mustard, cabbage, and carrots.In addition to the mentioned macro- and microelements, plants contain a number of elements in negligible quantities (from 108 to 10-12%), called ultramicroelements. These include cesium, cadmium, selenium, silver, rubidium, etc. The role of these elements in plants has not been studied.
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