Elements of a food
Mineral nutrients from the soil are used to build organs and form a crop. The term plant nutrients means a wide range of chemical elements or compounds necessary for the normal growth and development of plants. All of them are divided into macronutrients( used in large quantities) and trace elements( absorbed in small doses) and perform specific functions in plants in the formation of organic matter. Plants especially need nitrogen, phosphorus, sulfur, potassium, calcium, magnesium, iron, manganese, copper, zinc, molybdenum, boron and other elements, the content of which in different plants is not the same.
The ability of plants to absorb nutrients from the environment is determined by the quality and volume of the root system, which in turn depends on the type of plants, the external and internal conditions of development of the root mass. Plants assimilate nutrients throughout the entire growing season, but unevenly in separate phases of growth and development. The total removal of nutrients from the soil depends on the type of plant, variety, crop and food conditions. Assimilated nutrients are selectively fixed in various organs of plants.
The removal of nutrients from the soil by plants depends largely on the yield of the crop, the weather and other growing conditions: air and soil temperatures, the state of the soil as a whole, the degree of moisture, light, etc. In cold soils, little phosphorus enters the plants, and at this timethey need to be fed with phosphorus-containing fertilizers.
Vegetable cultures differ in terms of the number of elements of food, and in demanding them. By the degree of removal of nutrients from the soil, all vegetables can be divided into three groups: strong, medium and weak nutrient consumers.
To strong consumers of include white cabbage of late-ripening varieties, potatoes, especially early, table beet, club-new celery, rutabaga, cauliflower. These vegetables consume the greatest amount of nutrients. To , the average consumers of own tomatoes, leeks, carrots, spicy grasses, peppers, eggplant, pumpkin and legumes.
To , weak consumers of include lettuce, spinach, radish, cucumber, summer radish, onions that need a small amount of nutrients to build all their organs, but all elements must nevertheless be present in the soil in a balanced amount.
The need for nutrients depends on the culture, age and early maturity of the plants. Plants with with a short vegetation period ( early maturing) are the most demanding in providing food, as they form a crop quickly. This need is increasing,
Vegetable Crops by the degree-consumption of nutrients
1. Strong consumers. 2. Average consumers. 3 - Weak consumers of
if they, in addition, are located densely and have insufficiently developed root system. With for a prolonged growing season, plants use more nutrients than early maturing plants, but need less soil in their soil, since they have a more extended period of crop formation.
According to the assimilation of individual nutrients, vegetable cultures vary considerably. The highest requirements for soil fertility are produced by early-ripening green vegetables and seedlings, when the root system of plants is still poorly developed and has a low ability to absorb nutrients.
The need for plants in nutrients in different periods of vegetation is not the same. Vegetables carry most of the nutrients out of the soil during budding, flowering and fruiting. During intensive growth, from the emergence of shoots, plants need a continuous supply of nitrogen and phosphorus, during the formation of fruits - nitrogen, phosphorus and potassium. In this case, it is necessary to take into account the biological characteristics of the vegetable culture. So, cabbage consumes nitrogen more than carrots and beets, using it evenly throughout the period of growth and development. Onions, the root system of which is poorly developed, and also the majority of green crops, early-white and especially cauliflower require more nitrogen at the beginning of growth. Onion, tomato and cucumber most intensively consume potassium, then nitrogen and, finally, calcium and phosphorus.
All vegetable crops are rich in carbohydrates and have an increased need for potassium, but first of all they, especially early-ripening varieties, need nitrogen fertilizers. Consumption of nutrients increases with the growth and development of plants, but their removal per unit of mass in young plants is 2-3 times greater than in adults. The early fruiting of a cucumber and a tomato depends to a large extent on the availability of phosphorus to plants at the time of emergence. Cabbage and green plants at the beginning of vegetation are more responsive to nitrogenous ones, and in the period of quality formation - to pho-sap-potassium fertilizers. Fruit vegetable plants to ensure intensive growth, especially the root system, from the onset of seed germination require enhanced phosphorus, and with the formation of ovaries - nitrogen-potassium nutrition. Tomatoes and cucumbers make the most of nutritious elements during mass flowering and fruit formation, and early-ripening vegetable plants( radish, salad, spinach) - in the early and short terms.
Vegetable plants carry most of the potassium from the soil, less nitrogen and a small amount of phosphorus. This is due to the fact that sod-podzolic, sandy, sandy loamy, peaty soils are poor in exchange potassium, while others in the middle band are nitrogen.
Unequal chemical composition of leaves, flowers, fruits, plant roots - the reason that the need for plants in the diet varies throughout their life. Nutrients in the soil composition are in a related form, and the plants hardly receive them and are not fully used. It is established that from the soil reserves plants can take no more than 20 % nitrogen, 10% phosphorus and 10% potassium, while their removal by vegetable crops is much higher. It follows that nutrients must be supplied to the soil by fertilizer. The use of fertilizer nutrients is much higher: nitrogen - 60 %, phosphorus - 20, potassium - 50 %. Therefore, the stock of phosphorus available to plants in the soil should be about 10 times, nitrogen and potassium - 2 times more than this crop yields with yield. Even when the soil is able to fully satisfy the needs of plants in nutrients, fertilizers should nevertheless be introduced to maintain soil fertility.
If there is a shortage of any of the nutrient elements, the growth and development of plants is disrupted:
potassium is most often not enough on peaty, floodplain, sandy and sandy loamy soils;
of magnesium - on sandy, sandy-loamy, sod-podzolic;
calcium - on acidic and sandy;
molybdenum and boron - on acidic, soddy SUB-SOIL;
copper - on drained peat bogs.
The lack of one of the elements of mineral nutrition disrupts the normal course of metabolism in plants, which leads to external changes in the structure, size, color of leaves and stems, to the appearance of dead tissues of various colors and shades. When recognizing the signs of a shortage of individual cells, one should keep in mind that external changes in plants can also occur under the influence of other factors: lack or excess moisture, low temperature, and the effects of diseases and pests. So, similar in appearance can be signs of a lack of nitrogen and water, a lack of potassium and an excess of chlorine. Therefore, when diagnosing by appearance, it is necessary to take into account all the conditions of growth, development and needs of this vegetable culture. There are a number of basic signs in the appearance of plants that serve as a signal for the lack of individual nutrients.
Plants-indicators
Plants, whose appearance is easy to determine the lack of a particular nutrient in the soil, called indicators. So, the lack of gas and iron is more clearly manifested in white cabbage and cauliflower,
phosphorus - on turnip, swede,
potassium - on beet, cauliflower, beans,
magnesium, calcium - on color and leaf cabbage,
sodium - on beet,
boron - on beets and cauliflower,
manganese - on beets and cabbage,
molybdenum - on cabbage and salad.
Lack of nitrogen - pale green color and yellowing of leaves due to weakened chlorophyll production, reduced size and early yellowing or even necrosis of leaves.
The lack of phosphorus is a dark green, bluish color of the leaves, the appearance of red, purple hues, sealing of the leaf plate, the appearance of watery spots, dark, almost black, the color of drying leaves.
Potassium deficiency - yellowing, rust and dying of the leaf plate tissues, twisting down the edges of the leaf, wrinkling of the leaves, lethargy and sagging of the leaves.
Lack of calcium - damage and death of apical buds and roots.
Lack of magnesium - leaves clarification associated with insufficient formation of chlorophyll, a change in the green color of the leaves to yellow, red, purple at the edges and between veins.
The lack of iron - the appearance of uniform chlorosis between the veins of the leaf, pale green and yellow color of the leaves without tissue death.
Lack of sulfur - pale green color of leaves without tissue death.
The lack of copper - chlorosis and whitening of the tips of the leaves.
The disadvantage of boron is the death of apical buds, rootlets and leaves, lack of flowering, ovary failure.
Knowing how many and which nutrients in different periods of vegetation are necessary for one or another vegetable crop and which of them are present in insufficient quantity, you can program the yield of each of these crops. To improve the nutritional conditions for plants and to provide them with all the necessary elements, soil should be fertilized with
.
When developing a fertilizer system for vegetable crops, it is necessary to provide the right combination of organic and mineral fertilizers. Organic fertilizers, in addition to supplying with food elements and carbon dioxide, which improves the agrophysical properties of the soil, increase the activity of useful microflora in it, increase the content of organic matter.
Providing soil with mobile elements of mineral nutrition is one of the indispensable conditions for increasing the productivity of vegetable crops.
In this case, in specific soil and climatic conditions, a specific mineral nutrition system for various plants is required, allowing them to manage their growth and development.
However, it should be emphasized that the targeted improvement of the conditions for the nutrition of vegetable crops includes a whole range of measures: site selection, determination of the soil quality and proper preparation, regulation of heat and water regimes, plant care, crop rotation, reasonable fertilization, etc.
The reaction of vegetable crops to organic fertilizers
When choosing fertilizers, it is necessary to take into account the different requirements of vegetable crops to their types. According to the degree of responsiveness to organic fertilizers, cultures can be conditionally divided into three groups with different reactions:
highly responsive: late cabbage, cucumber, celery, spinach, asparagus;
medium-responding: early cabbage, cauliflower, beetroot, onion, carrot, tomato;
weakly responding: radish, radish, turnip, kohlrabi.
Based on this organic fertilizer should be used for cucumber, late cabbage, perennial vegetables. Carrots, cauliflower and early cabbage, onions, tomatoes, beets are best grown the next year after they are introduced.