Liming of acidic soils. Technology and timing of soil liming Liming of acidic soils leads to the following processes

Every experienced farmer knows what to get good harvest from your site, it is necessary to take into account the acidity of the soil. The initial acidity depends on the type of soil, but agrotechnical work leads to a gradual decrease in this parameter. Therefore, it is necessary to periodically deal with liming of the earth.

Why is soil acidity rising?

The acidity (pH) of the soil is a value that indicates the balance of hydrogen ions in the soil. To determine it, a scale from 1 to 14 units was adopted, in which pH = 7 corresponds to neutral soils, for acidic soils this indicator is lower, and for alkaline soils it is higher.

The decrease in the pH level occurs under the influence of the following factors:

abundant rainfall and watering, which leach salts into the deeper layers of the soil, in addition, the water itself can be acidic;
the introduction of peat, compost, fresh manure, sawdust, rotted needles;
cultivation and incorporation into the soil of some siderates, such as white mustard, rapeseed, oats, colza;
continuous use of mineral fertilizers, like ammonium nitrate, ammonium sulfate, potassium sulfate.

The scale indicates the initial acidity characteristic of the main types of soils

What are the signs of acidity?

In plants that are not adapted to grow on acidic soils, when the pH decreases, the diet is disturbed, they poorly absorb nitrogen, phosphorus, potassium and other elements. Plants grow worse, their yield decreases. Weeds help determine the acidity of the site: wheatgrass, thistle, dandelion, plantain, and heather grow well on slightly acidic and acidic soils.

More precisely, the pH value is determined by laboratory analysis. The most simple and accessible means for its independent implementation is a set of litmus papers, which can be purchased in specialized stores. Soil is taken from the study area to a depth of about 12 cm, mixed with water in a ratio of 1:5. Better if the water is distilled. When the earth settles, litmus paper is placed in the solution, after the color change, a comparison is made with the template.

With this kit, you can determine the acidity of the soil

Video: how to determine soil acidity at home

Liming the soil in autumn

Liming - effective method pH increase. The most suitable period for its implementation is autumn after harvesting from the beds. The time of work is chosen so that the earth is wet, but it can be easily loosened with a rake.

For liming, various substances containing calcium can be used. These include:

limestone (shell rock) - sedimentary rock with a high content of calcium carbonate;
chalk - a kind of limestone;
quicklime - calcium oxide;
slaked lime (fluff) - calcium hydroxide, working with the substance requires increased security measures;
- fertilizer obtained from carbonate rocks by grinding;
cement - construction material containing a significant amount of limestone.

How much lime to apply depends on the type and acidity of the soil.

Table: application rates for slaked lime (dolomite flour) in g / m 2

Crushed lime or other substance is evenly scattered over the surface of the soil and embedded into the soil at a shallow depth. Embedding can be omitted, but in this case, the efficiency of work is somewhat reduced.

Soil liming is the process of introducing special additives into the soil to reduce the level of acidity. For this purpose, you can use lime, chalk powder, lime tuff, marl, shale and peat ash, belite and dolomite flour, as well as cement dust and open-hearth slag. But, for example, sodium salts are not suitable for liming the soil, as it will become unsuitable for efficient crop cultivation.

Soil liming: when and why is it used?

The introduction of lime into the soil leads not only to the fact that the acidity of the soil decreases, but also to an increase in the proportion of calcium, magnesium and other useful micro and macro elements. Therefore, liming the soil is not only a decrease in acidity, but also an important fertilizer for plants.

The advantages of liming can also include an increase in the friability of the soil - such soil will absorb moisture well and keep it close to the surface. So the roots of the plants will receive optimal impregnation with water even in hot weather. In conditions of humidity and saturation with useful elements, soil microflora quickly develops, which leads to natural fertilizer beds. At the same time, root crops will not absorb a large amount of toxic substances, as it would be if liming had not been carried out on time.

It is impossible to simultaneously lime the soil and fertilize it with manure, as the result will be an insoluble and useless mixture for plants.

Too acidic soils adversely affect the development of crops. If the site has soil with high acidity, then it will be difficult to achieve a good harvest of all types of beets, as well as cabbage, and legumes. If the soil is also sandy, then the plantings will lack magnesium and calcium. Harmful to plants 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 in your area. The easiest way for this purpose is to use litmus papers or special devices to find the limit of soil acidity. If there is no opportunity to conduct an accurate analysis, you will have to rely on "folk remedies":

Weeds like horsetail and dandelion grow very quickly on soil with a lack of alkali. Sorrel, mint and plantain prefer acidic soil. On alkaline or neutral soil, clover, coltsfoot and quinoa grow well.
The topsoil in appearance resembles wood ash, in some areas a grayish coating is even noticeable on the surface.
Pay attention to the natural puddles and lowlands on the site - after the rain, the water turns red, sometimes an inconspicuous film of iridescent colors appears at the top.
Take a small handful of earth from the site and pour it with table vinegar. If nothing happens, this is also a sign of increased acidity (since vinegar is an acid, you should not expect a violent reaction when mixed with acidic soil). But if the earth began to hiss and foam, then it is either neutral or alkaline, in this case it is not necessary to carry out liming of the soil.

Soil liming and gypsum

Gypsuming differs from liming the soil with lime in that it not only reduces acidity, but allows you to get rid of excess sodium in the composition of the soil. Sodium negatively affects physical and Chemical properties land, and growing crops in such areas becomes much more difficult.

What chemical reactions take place after gypsum is added to the soil? The percentage of sodium decreases, and it is replaced by calcium abundantly introduced into the soil. Since calcium is useful for plants, its introduction has a positive effect on the growth of crops.

For gypsum, industrial wastes with a high content of gypsum and phosphorus, as well as raw ground gypsum, are usually used. To determine how much gypsum to add, first carry out biochemical analysis soil by determining the amount of sodium it contains. On average, from 3 to 15 tons of fertilizer will be needed, with solonetzes and solonetsous soils feeling the greatest need for gypsum.

Gypsum can be carried out during plowing, sowing perennials or irrigation. As a result, the yield of cultivated crops increases by 3-6 centners per hectare. At the same time, it should be taken into account that gypsuming of irrigated areas is most effective, but the reclamation period of the site is also reduced.

Types of lime fertilizers

For liming, both powders specially obtained by roasting or grinding (chalk, dolomite, limestone) and industrial waste with a high percentage of lime can be used.

The main means of liming the soil is lime flour, almost entirely composed of calcium carbonate (CaCO 3). If the mixture contains a large amount of magnesium carbonate (MgCO 3) in addition to calcium carbonate, then such a mixture is called dolomite flour. Magnesium rocks are more durable, and it is somewhat more difficult to obtain flour from them, but the result is a more useful fertilizer for crops. Sandy soils are the most deficient in magnesium salts, so pure lime is practically not used for them. To achieve a better 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 (this is especially important for industrial waste) and how fine the grinding is. Large particles have less solubility, so the soil "assimilates" them more slowly. For the greatest efficiency, it is desirable to choose limestone flour with a grinding thickness of no more than 0.25 mm.

Means for effective liming - slaked. This is a powder obtained by roasting limestone rocks, combined with water. Slaked lime or fluff in the first few years will neutralize the soil faster than ordinary lime meal. After several courses of liming, the effectiveness of these two compositions becomes approximately the same.

If it is not possible to carry out classical liming, at home you can use oven ash - it is poured under the root of acid-sensitive plants.

Soil liming: application rate

Usually, when calculating, they are guided by the so-called full norm - the amount of lime (tons per hectare), at which the acidity indicators decrease to a slightly acidic reaction.

Before calculating how much lime is needed per site, it is necessary to determine not only the area occupied by plantings, but also the following characteristics:

The mechanical composition of the soil.
The natural acidity of the soil on the site.
Features of crops grown in the area. For example, clover, cabbage and beets are sensitive to the application of lime fertilizers, so it is desirable to ensure the full rate of lime in the areas occupied by them. But it practically does not affect lupine or acidity - it makes no sense to overload the soil with lime, and therefore you can reduce the rate by one or two thirds.

The rate of liming of the soil with any particular mixture is calculated according to the following formula: H \u003d The rate of lime according to the acidity calculated in advance * 10000 and divided by the Percentage of lime in the mixture * (100 is the percentage of coarse particles).

Here the rate of lime 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 liming of acidic soil on a large scale, it is possible to pre-map the site with crops. In some places, the acidity may be higher, and vice versa, so for optimal placement of beds, you need to take into account the difference between soils.

Methods and timing of liming the soil

It is best to carry out liming of the soil in the spring before planting crops or in the autumn before digging up the beds so that the introduced substances do not remain on the surface. If spring liming is planned, then the procedure must be carried out no later than three weeks before planting.

Dolomite flour can be used for liming even in winter period- for this, it is scattered on the fields directly on top of the snow cover.

Primary liming is carried out before planting the dining room and fodder beet or cabbage. Other types of crops make it possible not to fertilize the soil with lime again and to alternate plantings, while the fertilizer efficiency does not decrease.

During the season, part of the introduced lime is lost, therefore, periodically (not necessarily every year) re-liming is carried out. For the first time, such an amount of lime or dolomite flour is introduced to completely neutralize the acidity of the soil. Repeatedly - only small doses, constantly monitoring 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 finely ground, then before being added to the soil, it is crushed to a powder state.
The finished composition is evenly distributed throughout the site.
Lime is mixed with the ground manually or with the help of agricultural machinery at a depth of 20-25 cm. If the procedure is repeated and not the full rate of lime is applied, then the depth of the loosened soil should not exceed 4-6 cm.

Autumn liming allows you to more accurately adjust the ratio of acids and alkalis in the soil, and the result will remain for a longer period than when lime is applied in the spring. Fertilizing with lime in autumn is also safer, as some formulations (such as slaked lime or wood ash) are quite caustic and can damage plant roots on direct contact. In this case, there is no need to loosen the ground deeply - after rain and snowfall, the mixtures naturally reach the required depth.

With the correct preliminary calculation, it will be necessary to repeat the 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, potash or even bacterial fertilizers. To ensure greater fertility, suitable and

Results of regular liming

Liming acidic soils is a simple and environmentally friendly way to increase the fertility of the land on the site. Factors due to which a positive effect is achieved:

activation of vital activity of some useful for garden plants microorganisms such as nodule bacteria, etc.;
increased water resistance and mechanical loosening of the soil, due to which water, together with fertilizers, does not leave the roots and tubers for a long time;
enrichment of the earth with useful elements (calcium, magnesium, fluorine);
preventing the absorption of toxic substances by plants - this is especially important for areas adjacent to industrial zones;
faster absorption of mineral elements.

All of these factors make it possible to harvest an environmentally friendly and rich harvest with the onset of autumn.

To make sure that timely liming of the soil is necessary, it is possible to 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 lime mixtures and their distribution over the territory, as well as the growth of crops in the years following liming. Obviously, the fastest payback can be achieved if liming is carried out on strongly acidic soils and subsequently planted crops that are sensitive to liming (vegetables, fodder plants and potatoes). As a result of neutralizing the soil, plants no longer suffer from the harmful effects of acids and receive much more nutrients than before.

Liming the soil in autumn - video

In crop rotations with potato specialization (more than 40% of sown areas), it is advisable to reduce the total doses by 20-25% on sandy and sandy soils. Magnesium-containing (dolomite flour, dolomitic and magnesian limestones) are more preferable. To prevent scab damage to tubers, lime is applied under potatoes before planting.

In crop rotations with flax specialization, an increase in pH over 6.0 is not recommended, the optimal pH values in sandy loamy varieties are 5.0-5.5, light and medium loamy - 5.3-5.8, heavy loamy and clayey - 5.5- 6.0. When full doses of lime are applied, the application rates of potash fertilizers are increased, boric and, if necessary, manganese fertilizers are used.

In areas where acid-sensitive crops are often cultivated, for example, fodder root crops, clover, alfalfa, full or one and a half doses of lime in terms of hydrolytic acidity are applied, followed by periodic maintenance liming.

IN vegetable crop rotations make full or on heavy soils one and a half doses of lime in terms of hydrolytic acidity, followed by systematic supporting liming. In these crop rotations, lime-silicate ( shale ash, cement dust) and magnesia-lime (dolomite flour) fertilizers.

By sensitivity to acidity, meadow grasses are divided into:

the most sensitive are alfalfa, sweet clover, sainfoin;
sensitive - meadow clover, hybrid and creeping;
moderately sensitive - fescue, foxtail, awnless bonfire, timothy.

The rates of lime application in meadows and pastures during grassing or reseeding of grasses do not differ from the doses for arable soils of field crop rotations, however, they are applied in layers: one half for the main cultivation (plowing), the other half for pre-sowing (disking). On lands with sod of small thickness, lime is applied superficially, followed by incorporation by disking or milling.

Despite a 25-40% decrease in calcium leaching in meadows and pastures (120-140 kg CaCO 3 / ha) compared to arable land, grasses as a result of the annual economic removal of calcium (100-120 kg CaCO 3 / ha) need maintenance liming.

Another reason for the rapid recovery of acidity after liming in long-term cultivated meadows and pastures is the introduction of large (up to 240–360 kg/ha) doses of nitrogen fertilizers under cereal grasses, the neutralization of which requires 500–700 kg CaCO3/ha annually.

With short-term (5-6 years) use of meadows and pastures, supporting liming, as well as phosphorite and organic fertilizers, is carried out during the period of repairs (replanting). With long-term (more than 10 years) intensive use, re-liming every 5-6 years is carried out after mowing and etching during the growing season with lime incorporation by disking or cutters.

Liming of acidic soils is carried out when laying gardens and berry fields with full doses of lime, taking into account the deepening of the arable horizon up to 35-40 cm in gardens and the characteristics of planted crops. So, under an apple tree, pear, plum, cherry, currant on loamy soils with a strongly and medium acidic pH value, at least 6-8 t CaCO 3 / ha are applied, on light and slightly acidic soils - 4-6 t CaCO 3 / ha, under raspberries and gooseberries - respectively 3-4 t CaCO 3 / ha and 2-3 t CaCO 3 / ha.

When laying orchards and berry fields, lime can be applied, mixed with soil, into planting pits: for plum and cherry - 3-5 kg CaCO 3, apple and pear - 2-3 kg CaCO 3, gooseberry - 0.1-0.2 kg CaCO 3 . Under adult fruit and berry crops, if liming was not carried out before planting, lime is applied for digging tree trunks in doses recommended for planting.

Gardeners and gardeners often face the problem of acidified soil. Such land does not allow you to get a rich harvest, and some crops do not take root on it at all.

The way out of this situation is to reduce the level of acidity by introducing into the soil various substances(in other words, deoxidation). The most common and inexpensive deoxidizer is lime.

However, it is impossible to thoughtlessly scatter it on the site, you must first decide which soil requires this and how much reagent to apply. About how to properly carry out liming of the soil, and there will be further discussion.

Purpose of liming

The main goal of liming acidic soils is to get a good harvest, since increased acidity harms some crops, inhibits them and slows down growth. alignment acid-base balance by adding lime (or other special additives) leads to the following positive results:

the level of toxic elements in grown root crops is reduced;
the soil is enriched with microelements;
the structure of the soil improves (it becomes more permeable);
increased activity of beneficial microorganisms;
plants develop better and faster (while in soil with high acidity, the activity of nitrogen, phosphorus and molybdenum is significantly reduced);
organic fertilizers applied to the soil give the crops of useful microelements 30-40% more (and in acidic soil they do not reach the root system in sufficient quantities).

Methods for determining soil acidity

When micronutrients enter the soil, chemical reaction, they break up into ions, which are actively absorbed by plants. The more hydrogen ions remain in the soil after decay, the higher the acidity of the soil.

Hydrogen activity and the degree of soil acidity are commonly referred to as pH:

in neutral - pH=7.0;
in acidic - pH less than 7.0;
in alkaline - pH more than 7.0.

But how to correctly determine this value and understand whether it makes sense to carry out liming of the soil? There are several ways.

Plants as an indicator of acidity

When not at hand special device or litmus paper, weeds growing in the country will help determine the acidity.

1. They prefer acidic soil: blueberries, chamomile, fern, field mint, plantain, pikulnik, core, tricolor violet, white-bearded, field speedwell, creeping buttercup, horsetail, heather, small sorrel, rosemary, horse sorrel, sedge.

2. They love alkaline soil: larkspur (otherwise called delphinium), poppy-seed, field mustard, white drowsiness.

3. Neutral soils like shepherd's purse, milkweed, chicory, adonis, field bindweed, garden thistle, white sweet clover.

4. Grow well on slightly acidic soil meadow clover, quinoa, nettle, wild rose, garden thistle, coltsfoot, creeping wheatgrass, wood lice.

indicator paper

The technology for determining soil acidity using litmus paper is as follows:

A hole is dug on the site (25-35 cm).
From the bottom they take a handful of earth.
Wet a little with rainwater (it is not recommended to take it from the water supply, such water contains chlorine, and the result may be inaccurate).
Indicator paper is applied to wet ground (it is sold in stores).
If the color has changed, it means either acidic (pink to red, pH 3 to 5) or alkaline (green to blue, pH 7 to 10).

Special instruments for measuring pH

You can buy devices for determining the level of acidity - testers. The rules of use are quite simple, while the measurement results will be the most accurate.

The tester is an indicator with a display on which measurement data is displayed, and a measuring probe immersed in the ground. With the help of the device, in addition to the pH level, it is possible to measure the temperature and degree of soil moisture, which is very convenient, especially during planting.

To correctly measure acidity, you must follow simple recommendations:

for accuracy, the readings must be taken several times and then the arithmetic mean value should be displayed;
the tester probe must be clean, free of dirt and oil stains;
during measurements, the probe must be completely immersed in the ground for its entire length;
measurement in dry soil is not carried out. It is necessary to first moisten it with rainwater and only after a few minutes, when the liquid is absorbed, immerse the probe.

Using folk methods

Whether soils require liming, gardeners determine using folk methods proven over the years.

The most faithful assistant is 9% table vinegar. From different areas in the garden, you need to take the soil, wet it with rainwater and after a few minutes pour a small amount of vinegar. The appearance of strong foam indicates acidic soil, and its absence indicates alkaline soil. If there is foam, but there is very little of it, then the soil is neutral.

The acidity of the soil will help determine the leaves of blackcurrant:

They must be poured with boiling water and insisted for half an hour.
In the resulting infusion, lower the soil samples.
Observe how the color of the liquid changes. A green tint indicates alkaline or neutral soil, Blue colour- about sour.

How to calculate the application rate

Ideally, for an accurate calculation of liming rates, one should contact the regional agrochemical center. The formula for the optimal dosage is quite complex and includes several parameters: from the particle size distribution and soil moisture conditions to the content of humus and mobile forms of phosphorus.

Approximate rates of lime application to the soil are given in the table:

Types of lime fertilizers

Lime additives not only neutralize the acidity of the soil, but also saturate it with calcium, which is so necessary for the active development of plants. In addition to lime, there are many other options, so we suggest that you familiarize yourself with the most common ones.

Depending on the method of extraction from natural rocks, lime fertilizers are divided into three groups:

Solid. The group is represented by dolomite, chalk and limestone. Such fertilizer still requires further grinding and roasting.
Soft. These additives do not require grinding (lake lime, marl, lime tuff, natural dolomite flour).
Waste industrial production which contain a lot of lime in their composition. Representatives of this group include defecation mud, cement dust, belite flour, peat and shale ash.
Fertilizers obtained as a result of processing natural rock (burnt lime).

For soil deoxidation, soft rocks of lime fertilizers are considered the best. In those regions where they are not mined, imported crushed additives are used. The most commonly used fertilizers are:

1. Fluffy lime (slaked). It is also used to whitewash tree trunks and control harmful insects.

2. Lake lime (limestone). It contains 90% lime in its composition, it is recommended to apply it simultaneously with organic fertilizers.

3. Quicklime. In addition to neutralizing acidity, it has also been widely used as a weed killer on heavy soils. However, the processing of quicklime in pure form not applicable, because it is lumps of different sizes and liming will not work out uniformly. It must first be extinguished at the rate of 100 kg of reagent 3.5-4 buckets of water (10 l). Lime will quickly absorb water, and when it dries, it will turn into a uniform powder, suitable for even distribution.

4. Tuff calcareous. It crumbles very well and does not require grinding. It contains 80% lime, which is brought in together with manure for digging.

5. Dolomite crushed (flour). This fertilizer is used to lime the soil in winter directly along the snow cover (if its height does not exceed 30 cm). Also, dolomite flour is used in greenhouse beds before planting.

6. Marl. Like tuff, it is brought in together with manure for digging. Used for light soils.

7. Chalk. They produce liming of the soil in the spring.

Do not mix lime fertilizers with superphosphate, urea, phosphate rock and ammonium nitrate. But with ash, potassium and sodium nitrate, they can not only be mixed, but also stored for a long time .

Fertilizer application technology for soil deoxidation

Liming is best done in mid-spring, before planting crops, or in the fall, before digging the garden. In these cases, the applied fertilizers will not remain on the surface. But it must be borne in mind that in the spring, the procedure should be carried out no later than 3 weeks before the start of planting. The exception is dolomite flour, it is scattered even in winter.

Liming can be basic (primary) and repeated (supporting):

The main liming is also called reclamation. It is used on soils with high acidity (pH = 5.5 or less). This procedure provides for the use of full norms of lime fertilizers.
Re-liming is used to preserve the acidity obtained during the main procedure - after all, under the influence of precipitation, part of the lime is washed out of the soil, and supporting fertilization compensates for this loss.

Depending on the type of soil, the full basic dose of lime lasts from 5 to 15 years. To maintain this level, once every 2-3 years, the soil is re-limed with a fertilizer application rate of 0.4 to 1.2 kg per 1 m 2.

The process of adding deoxidizing components to the soil is as follows:

If the fertilizer is not finely ground, it must be ground to a powder state.
The resulting product is evenly distributed throughout the site.
The fertilizer is mixed with the soil to a depth of 20-25 cm manually or using agricultural machinery (with repeated liming, 4-6 cm depth is sufficient).

When preparing a site for potatoes, liming is carried out in exceptional cases (when the soil is very strongly oxidized). For this crop, the optimum pH is between 5.5 and 6.0. Soil treatment with lime can cause scab damage to potatoes.

The specifics of the work in spring and autumn

Another advantage of autumn soil deoxidation is the incompatibility of some lime additives with nitrogen fertilizers: ammophos, ammonium sulfate, ammonium nitrate. These funds are applied to the soil in the spring, which means that in the fall you can safely fertilize the site with lime, they do not have to interact with each other.

In autumn, it is easier to determine the time of liming. In the spring, this is not so convenient to do, because it is necessary to complete the procedure 3 weeks before sowing, the timing of which cannot always be determined with accuracy.

The disadvantage of autumn liming is the incompatibility of some lime components with organic fertilizers, which are applied to the soil before winter.

Important! Liming is carried out only in dry weather, and there should not be a large amount of moisture in the soil.

As you can see, for a good harvest it is not enough to choose a quality planting material and ensure the plants are properly planted and cared for. Every gardener should have an idea of how to lime the soil in spring or autumn. But when exactly it is carried out, the personal decision of everyone - to whom it is convenient.

Everyone knows about the need to apply fertilizers to the beds and fields, but not everyone thinks about how they will assimilate nutrients cultivated plants. The availability of nitrogen and phosphorus for the roots largely depends on the acidity of the environment. To bring it to standard indicators, they use such an agrotechnical technique as liming the soil. This procedure seems to many not entirely clear, so it is worth justifying it.

Acids and alkalis in the soil

The difference between these two classes of compounds is the presence of hydrogen or a hydroxo group. H⁺ ions form acids, and OH⁻ - alkalis. The elements that are closer to the right side of the periodic table are more prone to the formation of the former, and the metals clinging to the left edge of the periodic system gravitate to the latter. Those elements that lie between them are called amphoteric. They can form both acids and alkalis.

Among the acids are well-known sulfuric H₂SO₄, nitric HNO₃, hydrochloric HCl, acetic CH₃COOH, hydrocyanic HCN and others. Alkalis - KOH, NaOH, Ca (OH)₂. Aluminum can participate in the creation of alkali Al (OH) ₃, but salts are widely used in industry, where this metal is part of the acid residue. They are called aluminates. For example, sodium aluminate has the formula NaAlO₂.

Hydrogen indicator

After adding additives to the ground, it must be dug up. During the winter, lime will react with the acids contained in the earth, and the reaction of calcareous soil will become neutral or completely slightly acidic. When applied in the spring, you can burn the roots with alkali. If the deadline is missed, it is better to use dolomite or chalk - they are less aggressive. They are more appropriate in sandy environments. Lime is useful in the abundance of clays and loams. Liming the soil with quicklime or magnesium oxide requires slaking with water before application. This is an exothermic process. It is not necessary to carry out it immediately before planting vegetables.

The frequency of liming depends on the nature of the soil in the region and on the site. For example, in wetlands, on the site of peatlands, this is done once every three years, and on heavy soils, the next treatment can be carried out once every 7 years. With a large amount of precipitation, this interval decreases.