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Soil liming is the process of adding special additives to the soil to reduce acidity. For this purpose, lime, chalk powder, calcareous tuff, marl, shale and peat ash, whitish and dolomite flour, as well as cement dust and open-hearth slag can be used. But, for example, sodium salts for liming soil will not work, as it will not be suitable for effective cultivation of crops.
Soil liming: when and for what use?
The introduction of lime into the soil leads not only to the fact that the acidity of the soil is reduced, but also to an increase in the proportion of calcium, magnesium and other useful micro- and macroelements. Therefore liming soil is not only a decrease in acidity, but also an important fertilizer for plants.
The advantages of liming can also be attributed to the increased looseness of the soil - this soil will absorb the moisture well and keep it close to the surface. So the roots of plants will receive optimal impregnation with water even in hot weather. In conditions of moisture and saturation, useful soil elements rapidly develop soil microflora, which leads to natural fertilization of beds. At the same time, root crops will not absorb a large amount of toxic substances, as it would be if liming were not performed on time.
You can not simultaneously lime the soil and fertilize it with manure, as a result will result in an insoluble and useless for plants mixture.
Too acid soils have a poor influence on the development of crops. If there is soil with high acidity on the site, it will be difficult to achieve a good harvest of all kinds of beet, as well as cabbage, corn and leguminous plants. If the soil is also sandy, the plantings will lack magnesium and calcium. Harmful to plants, the compounds of manganese and aluminum, on the contrary, will show increased activity.
Determination of soil acidity
At home, you can independently check whether liming of acidic soils is required on your site. It is easiest for this purpose to use litmus paper or special instruments to find the limit of the acidity of the soil. If there is no possibility to conduct an accurate analysis, we will have to rely on "people's means
- Weed grasses like the horsetail of the field and dandelion grow very quickly on the ground with a lack of alkali. Sour soil is preferred by sorrel, mint and plantain. On the alkaline or neutral ground clover, mother-and-stepmother and quinoa grow well.
- The upper layer of the soil resembles wood ashes, in some areas even a grayish coating is visible on the surface.
- Pay attention to the natural puddles and lowlands on the site - after the rain the water becomes red, sometimes a barely visible film of iridescent colors appears on top.
- Take a small handful of earth from the plot and pour it over the table with vinegar. If nothing happens - this is also a sign of increased acidity (since vinegar is acid, then a violent reaction when mixed with acidic soil should not be expected). But if the ground began to hiss and foam - then it is either neutral or alkaline, in this case, it is not necessary to conduct liming of soils.
Liming and gypsum of soil
Gypsum differs from liming the soil with lime in that it not only lowers acidity, but allows you to get rid of excess sodium in the soil. Sodium adversely affects the physical and chemical properties of the land, and the cultivation of crops in such areas is greatly complicated.
What chemical reactions occur after the gypsum is added to the soil? The percentage of sodium is reduced, and it is replaced by abundantly introduced into the soil by calcium. Since calcium is useful for plants, its application positively affects the growth of crops.
For gypsum, industrial waste with an increased content of gypsum and phosphorus, as well as raw gypsum, is usually used. To determine how much gypsum needs to be added, biochemical soil analysis is carried out first, determining the amount of sodium contained in it. On average, from 3 to 15 tons of fertilizer will be needed, and solonetzes and solonets soils are most needed for gypsum.
Gypsum can be carried out during plowing, sowing of perennial plants or irrigation. As a result, the yield of grown crops is increased by 3-6 quintals per hectare. It should be borne in mind that the most efficient is the casting of irrigated areas, but the meliorative period of the plot is also reduced.
Types of lime fertilizers
To carry out liming, powders (chalk, dolomite, limestone), or industrial waste with a high percentage of lime, can be used as a result of firing or grinding.
The main means of liming the soil is calcareous flour, almost entirely composed of calcium carbonate (CaCO3). If the mixture contains in addition to calcium carbonate a large amount of magnesium carbonate (MgCO3), then this mixture is called dolomite flour. Magnesium rocks are more durable, and it is somewhat more difficult to get flour from them, but as a result, fertilizer is more useful for crops. The greatest deficiency in magnesium salts is tested by sandy soils, so for them pure lime is practically not used. To achieve the best result, marl and even ordinary cement dust can be added to the mixture.
The quality of the powders introduced into the soil is determined by the percentage of calcium and magnesium carbonates (especially important for industrial wastes) and how thin the grinding is. Large particles have less solubility, so the soil "absorbs" them more slowly. For maximum efficiency, it is desirable to choose limestone flour with a grinding thickness of no more than 0.25 mm.
A means for effective liming is slaked lime. It is a powder obtained during calcination of limestone rocks, connected with water. Hydrated lime or pushetka in the first few years neutralizes the soil faster than conventional calcareous flour. After several courses of liming, the effectiveness of these two formulations becomes approximately equal.
If there is no possibility to carry out classical liming, at home it is possible to use ash ash - it is poured under the root of acids sensitive to acids.
Liming of soil: application rate
Usually in the calculation are guided by the so-called full rate - the amount of lime (tons per hectare), at which the acidity is reduced to a weakly acid reaction.
Before calculating how much lime is needed per plot, it is necessary to determine not only the area occupied by plantings, but also the following characteristics:
- Mechanical composition of the soil.
- The natural acidity of the soil on the site.
- Features of cultivated crops in a given territory. For example, clover, cabbage and beet are sensitive to the application of lime fertilizers, so it is desirable to ensure a full rate of lime in the areas occupied by them. But for lupine or potatoes the acidity practically does not influence - there is no sense to overload the soil with lime, and therefore one can reduce the norm by one-two-thirds.
The rate of liming of soil by any concrete mixture is calculated according to the following formula: H = Lime norm for calculated before the acidity * 1, 00 and divided by the percentage of lime in the mixture * (100-percent content of large particles).
Here the lime rate is taken into account in tons per hectare. Large particles are particles with a diameter of more than 1 mm.
If it is necessary to carry out the liming of acidic soil on a large scale, a map of the plot with the indication of crops can be made in advance. In some places acidity can be higher, and vice versa, therefore, for optimal placement of beds, it is necessary to take into account the difference between soils.
Methods and terms of liming soil
It is best to perform liming of the soil in the spring before planting crops or in the autumn before digging up the bed so that the added substances do not remain on the surface. If spring liming is planned, then the procedure should be carried out no later than three weeks before planting.
Dolomite flour can be used for liming even in winter - for this it is scattered in the fields directly over the snow cover.
Primary liming is carried out before planting table and forage beet or cabbage. Other types of crops do not fertilize the soil with lime repeatedly and alternate planting, while the effectiveness of fertilizer does not decrease.
During the season, some of the lime added is lost, therefore periodically (not necessarily every year) re-liming is carried out. For the first time such quantity of calcareous or dolomite flour is introduced to completely neutralize the acidity of the soil. Repeatedly - only small doses, constantly controlling the level of acidity and maintaining the optimal content of calcium and magnesium.
How to properly fertilize the soil with lime:
- If the lime or dolomite mixture is not sufficiently finely ground, before it is added to the ground, it is ground to a powder state.
- The finished composition is evenly distributed throughout the site.
- Manually or with the help of agricultural machinery, mix lime with soil at a depth of 20-25 cm. If the procedure is repeated, and the complete lime rate is not applied, the depth of the loosened soil should not exceed 4-6 cm.
Autumn liming makes it possible to more accurately adjust the ratio of acids and alkalis in the soil, and the result will be preserved for a longer period than when applying lime in the spring. Lime fertilization in autumn is also safer, as some compounds (eg, slaked lime or wood ash) are quite caustic and can damage the roots of plants with direct contact. In this case, there is no need to deeply loosen the ground - after a rain and snowfall, the mixtures naturally reach the required depth.
With the correct preliminary calculation, it is necessary to carry out the repeated procedure no earlier than in 5-7 years.
If desired, you can mix lime or dolomite flour, as well as gypsum powder with boric, copper, cobalt, potassium or even bacterial fertilizers. To ensure greater fertility, superphosphates are also suitable.
Results of regular liming
Liming of acidic soils is a simple and eco-friendly way to increase the fertility of land on the site. Factors due to which a positive effect is achieved:
- activation of vital activity of some microorganisms useful for garden plants, such as nodule bacteria, etc .;
- increase water resistance and mechanical loosening of the soil, due to which water, along with fertilizers, does not leave the roots and tubers long enough;
- the enrichment of the earth with useful elements (calcium, magnesium, fluorine);
- preventing the absorption of toxic substances by plants - especially important for areas adjacent to industrial zones;
- more rapid assimilation of mineral elements.
All these factors allow to collect an ecologically clean and rich harvest with the onset of autumn.
To ensure the need for timely liming of the soil, you can calculate the economic benefits of the procedure - payback time and net profit. To do this, it is necessary to calculate the costs for the purchase of calcareous mixtures and their distribution over the territory, as well as the growth of crops for subsequent years after liming. Obviously, the fastest payback can be achieved if liming on strongly acidic Soil and subsequently planted cultures that are sensitive to liming (vegetables, fodder plants and potatoes). As a result of neutralizing the soil, the plants no longer suffer from the harmful effects of acids and receive far more nutrients than before.