Can Root Nutrition Of Plants Be Managed (part 1)

2024 Author: Sebastian Paterson | [email protected]. Last modified: 2023-12-16 13:47

Root nutrition of plants is the most effective way of absorbing mineral nutrients (nitrogen, phosphorus, potassium, magnesium, calcium, sulfur, trace elements) and water. However, it is relatively rare for agricultural crops to find in the soil all the nutrients they need in an easily digestible form, in sufficient quantity and, which is very important, in the correct ratio.

Usually, in practice, plants are faced with a deficiency of two or three or more nutrients, without eliminating the deficiency of which the plant organism cannot develop normally and ensure high productivity. Therefore, scientists, having studied the laws of plant nutrition, proposed methods for managing this process: the use of fertilizers, optimization of the conditions for growth and development, and others.

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Before the use of fertilizers, the harvests in any country in the world were neither large nor stable. On the example of many countries it became clear that the harvest is increasingly becoming a function of the use of mineral fertilizers. It is well known that their rational use enhances plant nutrition, increases the yield, improves its quality, and at the same time makes the soil more fertile. However, the reasonable use of a wide range of fertilizers requires thorough knowledge of both the agrochemical properties of soils and the physiological characteristics of cultivated crops, not to mention the composition, types and quality of the fertilizers themselves. A surplus of fertilizer cannot replace a lack of knowledge. This article talks about root nutrition based on the theory of the matter. Although many people do not like the theory.

Some gardeners and vegetable growers, reading magazine articles, seek direct advice on fertilizer dosages. And this is not true. Fertilizer doses are not the most important and not the most important in the application of fertilizers. The most important thing is to first decide the "when?" to make, then - "where?", "as?" So what?" to make, and only then "how much?" …

Answer the question "When to fertilize?" knowledge of the physiological needs of plants in terms of growth and development phases will help. This is a big problem, in a nutshell, I will talk about them later. And now I will note that in accordance with the requirements of plants, three methods of fertilization are justified: basic, pre-sowing and top dressing.

The main fertilizer is food for intensive plant growth. It is applied in the spring (before sowing), but these fertilizers lie in the soil for a month (May) without being used by plants. And only at the beginning of June they begin to be used intensively, they are enough for only two to three weeks.

Pre -sowing - together with sowing, this fertilizer is used for only 5-10 days, then the roots go to other zones due to the drying out of the upper ten-centimeter soil layer.

Top dressing is carried out during the period of intensive plant growth (in summer, in June).

Therefore, fertilizers are applied in spring and summer. At other times, there is simply no point in applying fertilizers, since if there are no plants, then you do not need to introduce food in vain.

Let me remind you that before applying, you need to purchase fertilizers in advance, be free for this work, know the physiology of a particular plant and do everything intelligently. The answer to the questions "Where to add?" and "How to deposit?" can be obtained by studying the conditions of root and aerial nutrition of plants. "What to deposit?" - what nutritional element is needed at this time and in the form of what fertilizer it can be done is decided by the knowledge of fertilizers. And only after solving the previous questions can one answer the last one: "How much of the selected fertilizers should be applied?" …

Consider our problem: where and how to apply fertilizers

Root nutrition of plants is also called mineral nutrition. This concept includes the following interrelated processes occurring in a living plant organism and soil:

1. Correct use of mineral fertilizers, which are always applied to the moist soil layer to a depth of 10-18 cm. It is not possible to apply small amounts, since the top soil layer alternately dries and moistens in summer, which contributes to the transfer of soluble fertilizers into forms inaccessible to plants. Therefore, the roots do not grow in this layer and fertilizers are ineffective here. Their introduction into deeper soil layers (deeper than 18 cm) sharply accelerates the leaching of fertilizers into the underlying horizons and causes groundwater pollution, which is unacceptable.

2. Directed development of the root system in places where fertilizers have been applied or where there are soil reserves of nutrients. This is facilitated by chemotropism - the property of the roots to grow in the direction where the most nutrients are located. Therefore, fertilizers in the spring before sowing are applied to the root layer - from 10 to 18 cm, and when feeding, they are placed at a depth of 10-12 cm in the row spacing, next to the protective zone, from which the roots grow towards the applied fertilizers.

3. Active influence of plants on the soil through the release of acids and enzymes by the roots that can destroy mineral and organic substances of fertilizers and the solid phase of the soil. This helps translate elements into more easily accessible forms. More root exudates enter the soil if the plants are well fed from the air, this gives the roots energy and carbohydrates. To do this, you need to sow the plants correctly so that they do not shade later and have an optimal nutritional area. For example, an apple and a pear must have a feeding area of at least 7x3 m, plums and cherries - 4x4 m, currants and gooseberries - 2x1.5 m, strawberries - 0.8x0.2 m, etc.

4. The movement of the soil solution to the surface of the active part of the root system or the movement of salts to it by diffusion. These processes can be enhanced by good soil cultivation and optimal watering. In the spring, early harrowing should be carried out to close the moisture, then digging 18 cm with fertilization and harrowing, flat-cut cultivation before sowing early crops, cultivation with a hoe or a second flat-cut cultivation for late crops. In the summer, two or three cultivations of row crops are carried out with the introduction of fertilizers, weed control by harrowing or flat-cutting processing, digging after harvesting.

5. Absorption of salts by root hairs by exchange adsorption of ions by cell membranes and protoplasmic membranes. To do this, fertilizers need to be applied between the rows, immediately after the protective zone (near the trunk circle for fruit and berry crops), outside of which young roots and root hairs develop, which are occupied by the absorption of fertilizers and water. Conductive large roots are located in the protective zone, therefore no treatments are carried out there and fertilizers are not applied there, since these roots cannot absorb nutrients. Growing young roots are located further than this zone in the row spacing, where fertilizers are applied.

6. Synthesis of amino acids and proteins from the incoming substances. The process starts at the roots and ends at the leaves. For the synthesis of plastic substances, plants need a variety of nutrients - both macro- and microelements. Therefore, fertilizers are applied in a complex spring (organic plus mineral: nitrogen, phosphorus, potassium and micronutrient fertilizers), in a complete set, so that there is no starvation of plants due to a lack of certain elements, so that synthetic processes prevail over decay processes during root respiration. In the summer, they additionally give dressings with macro and microelements.

7. Exchange of organic and mineral compounds between leaves and roots, between air and root nutrition of plants. This enhances synthetic processes. If the leaves work well, then the roots are well supplied with plastic substances. Conversely, if the roots absorb the entire set of nutrients, then by doing so they better supply the leaves with amino acids and other plastic substances and better promote carbon dioxide nutrition through the leaves.

8. Exchange of secretions (mineral and organic compounds) between roots and soil microorganisms. Plants supply the soil microflora mainly with organic substances, from which the latter draw energy, and in return from microorganisms they receive additional mineral compounds in the process of decomposition of organic fertilizers. And overall nutrition is improving.

9. Secondary use (recycling) of nutrients and their movement from leaves to reproductive organs.

In the second half of summer, plants absorb less nutrients from the soil and use more previously absorbed substances. Therefore, it is important to give full fertilization in the spring and top dressing in the first half of summer, so that the plants accumulate the required amount of food in the leaves for subsequent nutrition in the second half of the growing season to create a good marketable crop. At the same time, it is important to achieve the correct ratio between nutrients, so that in the second half of the summer there is no excess of nitrogen and a good supply of phosphorus and potassium is created. Therefore, at the beginning of August, fertilizing of fruit and berry crops with phosphorus-potassium fertilizers is carried out.

In accordance with the noted rules of root nutrition, it is necessary to develop a fertilizer application technology. It should be understood as a complex of sequentially performed operations that meet the biological requirements of plants.

The main fertilizers are applied in spring, most often by a continuous method. First, we calculate the rate of fertilization for a specific crop and for a specific area (the area should be feasible so that you can dig up and finish the work in half a day). Then we evenly sow fertilizers one after another: lime, nitrogen, potash, phosphorus, micronutrient fertilizers and, finally, organic fertilizers. We dig up the soil with a turnover of the layer, carefully break all the lumps from above, embedding fertilizers in a layer from 8-10 to 15-18 cm. All operations are performed sequentially, without interruption, in order to avoid the occurrence of unwanted chemical reactions between various fertilizers (loss of solubility of fertilizers, loss of elements food in the form of gaseous products into the air, etc.).

Seeding fertilizer is applied line by line. A groove is made into which superphosphate is sown with a line at a dose of 5-7 g / m², sprinkled with soil (1-2 cm layer), then seeds are sown and sealed.

Top dressing is carried out in a line or continuous way. In the row spacing next to the protective zone, a 12 cm deep groove is made along the row, at the bottom of which nitrogen-potash fertilizers are sown in rows and sprinkled with soil. You can also make a continuous method. To do this, fertilizers are scattered throughout the entire row spacing (except for the protective zones), then they are sealed with a shovel - the soil is dug with a seam turn to a depth of 12 cm, then it is carefully loosened with the same shovel or rake.