Corn has specific requirements for the soil on which it will be grown. First of all, it is deep plowing, which is necessary for the proper development of the root system. The second point to be taken into account is that corn does not tolerate acidic pH values (preferably, when it is 6.0-7.0), it does not grow well on overmoistened and saline soils. As a rule, the yield at pH less 5.5 is significantly reduced, if the acidity value is 5.0 or less, then the soil chalking should be done. It is desirable to carry out such tillage already under the predecessor culture.
Corn has a strong root system, most of which is located at a depth of 0-20 cm.
The absorption of minerals is uneven. 80% of the total potassium that the plant will need is absorbed from the soil during the first growing season, therefore, the farmer must ensure that it is present in the soil. The remaining elements will be predominantly acquired in the time interval from the ejection phase of the panicle to the milky ripeness of the grain. But the presence of phosphorus at the start is also necessary - for the development of the root system and creating the cobs.
By the time of the milk ripeness of the grain, corn should accumulate 90% of all nutrients and 80% of dry matter. In order to form 1 ton of grain, corn takes up from the soil:
Directly during the growth of the culture, two critical periods are distinguished: phases 3-5 and 7-8 leaves. During the initial period (when the first above-ground node is not yet present), corn grows very slowly. Another factor that slows growth at the initial stage is the stress of using herbicides.
A sufficient amount of phosphorus at the initial stage has a direct impact on the future harvest - if this mineral is enough for a plant, the maximum possible number of cobs on a plant and grains in each of them is laid. To accelerate the development of the root system of corn at the initial stage of its growth, it is important to provide the plant with phosphorus, manganese, zinc and boron.
In the second critical phase (7-8 leaves), corn, on the contrary, grows very intensively. Good mineral nutrition at this stage means better quality of the cobs and increases the quality of the grain itself. It is important to remember that the lack of minerals at this stage is no longer corrected by additional feeding, since it is now that roots, stem and generative organs are being formed.
The use of nitrogen fertilizer for corn
Nitrogen more than others affects the yield of corn. Before the phase of the 6th leaflet, its assimilation is very insignificant (5% of everything that will be absorbed by the plant). But from the phase of the 6th leaf to the ejection of the panicle 60% of the total nitrogen (100-120 kg/ha) is absorbed. If there is not enough nitrogen in the soil, inter-row application will help at this stage. Correct selection of the dose and term of application improves the yield, the amount of protein in the green mass and grains.
Loam soils stand separately - most of the nitrogen, phosphorus and potassium should come here as the main fertilizer, but not top-dressing.
Caution should be exercised on sod-podzolic soils - they have poorly expressed buffer properties. Therefore, with interrow fertilizer there is a risk of getting a negative reaction from the plants.
Phosphorus in the cultivation of corn
As with many cultures, phosphorus improves the growth of the root system. Therefore, preplant phosphorus application improves the development of the root system at the initial stage. At subsequent stages, the lack of phosphorus inhibits the growth and development of grains on the cob, the leaves become dark green with a purple-red shade and gradually die off.
Potassium - Signs of Deficiency and Importance to Corn
Like many carbohydrate-rich crops, corn has an increased need for potassium. Potassium value for corn:
As already mentioned, an interesting feature of corn is that it absorbs 80% of all potassium at the initial stage of growth. Be sure to make potassium in the soil, if before that it grew sunflowers, roots or potatoes.
Potassium deficiency is manifested in corn as follows:
It is possible that all the plants on the field receive less potassium and the symptoms described above are difficult to detect, since there is nothing to compare with. In order to avoid such a situation, on the field with corn there must necessarily be a control plot in which the plants are precisely supplied with potassium.
The selection of the dose depends on the dose of nitrogen that is applied to the same field. Usually, 90% of the potassium of the amount that corn takes out of the soil (30 kg/ha) should be added. If nitrogen was introduced in a high dose (more than 120 kg/ha), then it is better to close all 100% of the potassium requirement, which has a positive effect on the formation of cobs and grains in them.
Corn, faster than other cereals, absorbs water from the soil, and therefore tolerates drought quite easily.
For corn, there are three methods of fertilizer application:
This crop requires higher doses of fertilizer than other cereals. For fertilizers can be used green plants, manure, mineral fertilizers.
The application of manure on the black soil of the forest-steppe at a dose of 20 t/ha increases the yield from 0.4 to 0.9 t/ha.
On loamy soils, manure, phosphate and potash fertilizers for corn are applied in the fall for autumn tillage, and nitrogen in the spring for cultivation. If sandy and sandy soils are sufficiently moist, then it is better to bring manure in spring.
If it is planned to grow this crop in one field for two years in a row, then in the first year manure (50 t/ha) and a full dose of mineral are applied, and in the second year only mineral fertilizers. Correction of the application for the first year is possible - if there is more manure than 50 t/ha, then only nitrogen (not more than 100 kg/ha) can be left as mineral.
Excessive moisture on the field, abundant irrigation leads to increased action of nitrogen fertilizers and weakening of phosphate and potash fertilizers.
The approximate dose of mineral fertilizers to obtain 10 t/ha of corn is:
Top dressing does not eliminate the need for basic fertilizer application, but accelerates ripening, if done in the phase of 3-5 leaves. Later feeding is less effective and leads to a lengthening of the growing season of corn.
To improve the yield, make a good feeding before the start of the throwing the panicle.
Sulfur
Sulfur is an important mineral - a shortage of 1 kg of sulfur leads to a violation of the assimilation of 10 kg of nitrogen. Plants lose color due to the decomposition of chlorophyll, cobs lose grain. To correct the deficiency of sulfur, foliar application of magnesium sulfate (3-5% solution) is used along with urea solution (6-8% solution). Spraying of crops should be carried out in the morning or in the evening when the air temperature is lower.
Manganese
Manganese plays an important role in plant metabolism. It is part of chlorophyll and is involved in the synthesis of proteins. With its deficiency, you can see the uneven yellow color between the veins on the old leaves. Manganese deficiency often occurs on soils of light particle size, with high concentrations of potassium on the background of cold and wet weather. The recommended dose of application is 40-60 kg/ha.
On 1 ton of grain, corn takes up from the soil:
Zinc
Zinc is very important for the proper metabolism of phosphorus, with a high content of humus in the soil, in the cold and during the alkaline reaction of the soil. With a lack of zinc, pale yellow stripes appear on young leaves, or the entire surface of the leaf becomes yellow and white. Badly damaged leaves turn red.
Boron
Boron is important for pollination, as it promotes the growth of pollen tubes. Its shortage is often observed on sandy soils.
Copper
Copper is important for redox processes. Its sufficient amount increases the content of protein, sugars, lignin. With a lack of copper, plant growth slows down, the interstices shorten, the edges of the leaves dry out. You can expect the occurrence of copper starvation on the background of the use of high doses of nitrogen and phosphate fertilizers.
At low temperatures or during droughts, foliar application of trace elements is recommended. But at the same time, do not forget that excess doses can do more harm than the symptoms of their deficiency.
