When answering the question of which soils require liming, one must proceed from the group of crops that plants you are going to cultivate in a particular area. The fact is that not all of them react equally to soil pH.
The concept of liming
This agricultural practice is practiced on soils that have a pH less than 7. As you know, in this case, in the soil-absorbing complex (PPC), in which there is a hydrogen ion, when interacting with calcareous materials, it is replaced by a calcium ion, which helps to neutralize the medium under consideration .
Thus, the question of which soils require liming suggests a definite answer: acidic.
Plant groups in relation to acidity
Each plant organism has its own optimal environment in which it is convenient and convenient for it to grow and develop. Therefore, liming of soils is not carried out under all cultivated plants. They are usually divided into certain groups depending on the relationship to soil acidity:
- Medium that does not tolerate an acid reaction - cabbage, various types of beets, alfalfa - strongly respond to the application of calcareous materials even on slightly acidic soils.
- Sensitive to high acidity, preferring neutral soils and responding well to the method under consideration: wheat, barley, corn, sunflower, lettuce, cucumber, onions, legumes - respond positively to liming the soil with a rate of one and a half hydrolytic acidity.
- Plants that can tolerate low acidification and grow on slightly acidic soils. On medium and strongly acidic soils, liming is carried out for them by full norms. These include: carrots, radishes, tomatoes, rye, millet, oats.
- Crops for which liming should be carried out with caution, only on medium and strongly acidic soils: potatoes, flax. Excessive application of lime reduces the yield of potatoes, and its tubers are more affected by scab.
- Those who do not like liming the soil of culture: lupine, tea bush, seradella. They can grow on strongly acidic soils. Liming reduces yield.
Most crops respond positively to liming.
For beets and cabbage, liming is carried out directly in the year of their planting. Other vegetables are planted on manufactured sites in subsequent years.
Lime ameliorants
Can liming the soil:
- quicklime and quicklime;
- lake (drywall);
- burnt;
- limestone;
- calcite;
- cement dust;
- sugar production waste;
- dolomite flour;
- lime tufa;
- marl deposition.
Calcium tuffs are found in places where keys exit to the surface, along the banks of various reservoirs, on the slopes of cliffs and root banks. The effect is faster compared to ground limestone, but slower when compared with burnt lime.
The lake variety of chemical ameliorant is mined in place of enclosed bodies of water that existed in this place in the past, as well as in former peat depressions. Its effect is faster compared to calcareous tuffs.
Dolomite flour contains not only calcium, but also magnesium. Its effect is slower compared to calcareous tuffs that contain only calcium. Dolomite flour is made from a mineral by grinding it to the smallest fractions. It not only normalizes the acidity of the soil, but also improves the structure of the upper fertile layer.
Mergel is limestone, which contains a large amount of impurities such as clay and sand. It is extracted from deposits common in the podzolic zone.
Burnt lime is slaked (fluff) and quicklime. Extinguishing can be done at home using water, without approaching the solution during boiling. This type of ameliorant is obtained by burning solid limestones. One ton of quicklime or 1.5 tons of quicklime is equivalent to 2 tons of lime flour.
The quality of lime flour is mainly determined by the quality of grinding. The finer it is, the better the meliorant is.
In places of distribution of the apatite industry, nepheline wastes and shale ash are used.
If it is impossible to use special calcareous materials, you can use a synthetic mineral fertilizer called "Superphosphate", which, in addition to phosphorus, contains calcium in its composition. However, it is believed that it is associated with the main element and sulfur, which makes it inaccessible to regulate the acidity of the soil.
Some suggest that gypsum materials can be used. However, this is a misconception. They are used in the opposite case, when the reaction of the medium is alkaline.
Determination of soil acidity
It can be determined visually by the presence of indicator plants. These include, first of all, plantain, horsetail, horse sorrel, horseradish. However, they can also develop on soils that are not acidic. In addition, their presence is difficult to judge the degree of acidity of this type of substrate.
Therefore, the most reliable method is laboratory tests using special instruments: ionometers or pH meters.
Liming dates for acidic soils
Especially zealous when making such ameliorants is not worth it. At high doses, as with sufficiently private use, the access of plants to other nutrients, primarily such as potassium, magnesium, phosphorus, decreases. The water regime is complicated, their immunity to various diseases is reduced.
Scientists and researchers involved in agrochemistry are advised to carry out soil liming at certain times: thoroughly once every five years. If the soil is strongly acidic, then annual use of lime is allowed, in small portions for autumn (autumn) plowing (digging).
It is most effective to use this reclamant, like any fertilizer, in a local way. It is much more efficient than scatter. Liming for vegetables is carried out a week before they are planted.
Norms
In the scientific literature, it is recommended to calculate the application rate when liming soil ameliorants, based on hydrolytic acidity. The maximum dose should be 1.5 of this value, if necessary, it can be reduced to a single.
However, this indicator can only be determined chemically in the laboratory. Therefore, the norms of liming of the soil are set based on the pH of a particular substrate. So, for sandy and light loamy soil, 25 to 40 kg / hectare is required, depending on its acidity level. For medium and heavy loamy substrates, the norm is increased by about 1.5 times.
When re-liming the dose of the used meliorants is reduced by 50-65%.
Their combined use with manure contributes to the rapidly proceeding mineralization of organic substances. Decaying, manure contributes to the enrichment of the surface layer of soil 2 , which, in turn, accelerates the process of dissolution of calcareous materials.
Conducting autumn reclamation
When liming acidic soil in autumn its chemical properties improve. The need for its implementation can also be determined by indicator plants, which include alfalfa and field wildlife. In case of abundant growth of these plants on the soil, we can say that there are enough calcareous materials in it. An accurate determination of the pH of the medium is carried out using an ionometer.
Liming is carried out during autumn soil preparation work . During the appearance of seedlings, lime should not be added. Calcium, which is part of it, contributes to the compaction of the substrate, which can impair the development of agricultural plants and even lead to their complete death.
During the application period there should be no precipitation, as well as moisture stagnation on the soil surface.
Some sources indicate that lime should not be added together with organic fertilizers, although other authors write that mixing of such materials with manure is allowed. It is undesirable to combine them with ammonia forms of nitrogen fertilizers.
Garden liming
Initial measures for the implementation of these reclamation works are carried out at the stage of laying nurseries. They are also carried out in the autumn, combining with the introduction of organic fertilizers. The liming of the soil can be carried out in the winter period by using dolomite flour in the snow, but at the same time, the thickness of its cover should not exceed 30 cm.
Precautions
Like any reclamation measure, liming of the soil must be carried out using personal protective equipment. Work is carried out in goggles, as well as in rubber gloves. Liming should not be done in windy weather. If it is impossible to use plows or cultivators for plowing lime, it must be scented immediately after spreading with a shovel or pitchfork.
Particular care must be taken when working with slaked and quicklime. If it gets into your eyes, lay the victim on his back and rinse them with a stream of water. Then, castor oil is instilled into the eyes or ointment is laid, after which they consult a doctor.
Finally
In this article, we examined the process of liming acidic soils, the timing and norms of the use of chemical reclamants. They need to be used not for all cultures, the main refueling should be carried out once every five years. It is best to soil them in the fall. On sandy substrates, it is necessary to carry out maintenance liming annually at reduced rates. Full rates are calculated by hydrolytic acidity or by pH. When working with these chemical reclamants, safety precautions must be observed.