11 Conditions For Using Lime Fertilizers

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

Why lime soils (part 3)

Read the previous part of the article: Calcium and Magnesium in Plant Nutrition. Lime fertilizers

With liming of acidic soils, plant nutrition with nitrogen and ash elements - phosphorus, calcium, magnesium and molybdenum - improves. Improved nutrition on limed soils is also explained by the fact that plants develop a more powerful root system and therefore are more able to absorb nutrients from soil and fertilizers. However, this cannot happen automatically. A number of conditions must be met.

1. Liming should be carried out regularly - once every five to six years. Under the influence of the processes taking place in the soil and the applied fertilizers, the reaction of the environment changes, after about five to six years it returns to its original level, therefore liming must be repeated periodically.

2. The positive effect of liming on most agricultural crops is fully manifested only when the ratio in the soil solution and the absorbing complex of the soil of calcium and magnesium is favorable for their growth and development. Plants can develop at different ratios between these cations, however, the best conditions for most plants are created when the ratio between Ca and Mg is 100: 40-80, that is, 40-80 parts of Mg are available for 100 parts of Ca.

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In strongly acidic soddy-podzolic soils, poorly saturated with bases, especially of light texture, there is less magnesium absorbed than is required to create a favorable ratio between it and calcium. When lime fertilizers containing only CaCO3 are applied, the unfavorable ratio between these elements expands even more. Their too wide ratio in the absorbing complex and soil solution is the reason for the reduced efficiency and even the negative effect of lime on some plants.

The introduction of lime materials containing, along with calcium, a significant amount of magnesium, improves the ratio between these elements and therefore increases the yield of many crops more than the use of lime fertilizers that do not contain magnesium. Therefore, when applying lime fertilizers containing only calcium, it is advisable to use them in conjunction with the corresponding magnesium fertilizers.

3. The effect of lime increases significantly when combined with organic and mineral fertilizers, especially with manure, superphosphate, potash, boric, copper, cobalt and bacterial fertilizers, which accelerate soil physicochemical reactions and more significantly increase soil fertility.

4. Before adding lime, you first need to determine the degree of need for the suburban area in liming. It is known that the higher the acidity of the soil, the more the soil needs lime and the greater the increase in yield from liming. However, on slightly acidic and neutral soils, this technique does not give a significant effect. Therefore, before adding lime, you need to make sure of the need (need) for liming.

The need for liming can be roughly determined by some external features of the soil. Strongly acidic soils have a whitish, gray tint, a pronounced podzolic horizon, reaching 10 centimeters or more in thickness. Such soils require liming in the first place.

The need for liming can be determined by the condition of some cultivated plants and the development of weeds. Poor growth and strong thinning of clover, beets, wheat and other crops most sensitive to high acidity (despite good agricultural practices, proper fertilization and other favorable conditions) indicate a high degree of liming need. The first two groups of plants strongly need liming, they do not tolerate excessive acidity, the third and fourth groups have an average need, and the fifth group of plants grows well on acidic soils and does not need liming. Some weeds and wild plants - sorrel, field coryza, pikulnik, creeping buttercup, whitebird, pike, rush, wild rosemary, heather and others - grow well on acidic soils. Their abundant distribution on fields and roadsides indicates an increased acidity of the soil and the primary need for lime application.

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The degree of soil acidity is an important, but not the only indicator characterizing the need for liming in soils. More precisely, the degree of need of plants for liming can be established on the basis of a complete agrochemical analysis of the soil, determination of the exchangeable acidity (pH of the salt extract) and the degree of its saturation with bases (V), its mechanical composition.

Depending on the exchangeable acidity with an average humus content (2-3%), soils are subdivided according to the degree of need for liming as follows: at pH 4.5 and below - the need is strong, from 4.6 to 5.0 - medium, from 5, 1 to 5.5 - weak and at a pH above 5.5 - the soil does not need liming.

Depending on the degree of saturation with bases, the soils are divided into the following groups: V = 50% and below - the need for liming is strong, 50-70% - medium, 70% and above - weak, more than 80% - the soil does not need liming.

The high content of aluminum, manganese, iron is also an important reason for the need for liming.

Liming can also serve as a means of obtaining hygienically healthy crop products, a means of reducing the harmful effects of heavy metals and radionuclides, the accumulation of which is associated not with acidity, but with pollution due to unreasonable human activities. In the presence of these signs, the need for liming increases greatly. With technogenic pollution of soils, the need for liming is high, although according to the usual agrochemical parameters, they may not need lime at all.

5. Lime fertilizers should be applied in optimal doses. With a strong need, full doses of lime are used, with an average one - you can do with half doses, with a weak one - in small doses or use a neutralizing lime additive.

The amount of lime required to reduce the increased acidity of the arable soil layer to a slightly acidic reaction (pH of the water extract 6.2-6.5, salt extract 5.6-5.8), favorable for most crops and beneficial microorganisms, is called the full or normal dose … More precisely, the full dose of lime can be determined by the hydrolytic acidity. To calculate in this way the dose of lime (in grams of CaCO3 per 1 m²), multiply the value of hydrolytic acidity (Hg), expressed in meq. per 100 g of soil, by a factor of 150. Dose of CaCOz = NG150.

The dose of lime can be determined both by the pH value and the mechanical composition of the soil. At pH less than 4.5 on sandy loam and light loamy soils, the dose is 800-900 g / m2, and on medium and heavy loamy soils - 900-1200 g / m2, at pH 4.6-5.0 it is equal to 500-800, respectively, at pH 5.1-5.5 - 200 and 400 g / m².

There are complex methods for determining the doses of lime, but we will talk about them a little later.

6. Depending on the economic conditions, it is necessary to select the optimal methods of lime application. A full dose of lime can be applied to the soil all at once or in several steps. When a full dose is applied in one step, a faster and more complete neutralization of the acidity of the entire arable layer of soil for a long time is achieved and higher yield increases for most agricultural crops are obtained. The introduction of a full dose of lime is especially important when cultivating crops that are sensitive to acidity on strongly acidic soils, as well as when deepening the arable layer of poorly cultivated sod-podzolic soils.

If it is not possible to apply a full dose of lime to the entire area of acidic soils at once, then liming is carried out in several stages. Instead of the full dose, you can use half the dose. In this case, twice the area is lime. However, the increase in yield from each square meter in this case will be 20-30% less, although the total increase from the entire area to which lime is applied will be higher in the first years than from the use of the full dose, but on an area that is half as much … In the first years after application, the difference in the effectiveness of the full and half dose of lime is relatively small. However, in the second-third and subsequent years, the increase in yield from a half dose becomes almost two times less than from a full dose.

A full dose of lime has a positive effect on the yield on medium and heavy loamy soils for 5 years, and on soils with light texture - 2-4 years. The positive effect of a half dose is less lasting than a full dose, therefore, the second half of the dose is reintroduced in the same area after 1-2 years.

With the systematic use of mineral fertilizers, especially physiologically acidic fertilizers, the loss of calcium and magnesium increases significantly, and a more rapid acidification of previously limed soils occurs. In this case, re-liming should be carried out after a shorter period.

The introduction of lime in small doses may be advisable only as an additional measure to increase yields in combination with other methods of using lime fertilizers, in particular, when acid-sensitive crops are sown on strongly acidic soil, and it is not possible or undesirable to apply the full dose. For example, if crop rotations with flax and potatoes have crops such as clover, wheat, barley, peas, beets, corn, then it is advisable to combine the introduction of a half dose of lime for plowing with local application of small doses (50-100 g / m2) in rows when sowing a culture sensitive to an acid reaction. Spread application of a half dose of lime provides an optimal reaction of the medium for crops of the second-fourth group, and local application against this background of small doses of lime creates favorable conditions for plant growth,more sensitive to acidic reactions.

A small amount of lime is also used in combination with mineral fertilizers to neutralize their potential acidity. In this case, lime is called a neutralizing additive to mineral fertilizers. At the same time, further acidification of the soil is prevented due to the physiological acidity of fertilizers, which sharply increases the efficiency of all fertilizers.

To neutralize the acidity of 1 kg of ammonium sulfate, 1.3 kg of CaCO3 are required, 1 kg of ammonium nitrate - 1 kg of CaCO3 and 1 kg of superphosphate - 0.1 kg of CaCO3. On average, it is believed that for each kg of mineral fertilizers, 1 kg of lime must be added to neutralize.

7. Lime is introduced taking into account the agricultural technology used. Full doses of lime are added for digging in spring or summer after harvesting the main crop. In principle, lime can be applied in spring, summer or autumn. But it is better when the soil is being digged. It's spring or summer. The best time is spring, when mineral and organic fertilizers are applied. Then lime dissolves better and better reduces the acidity of the soil and the physiological acidity of fertilizers.

8. Application of lime fertilizers should be carried out taking into account crop rotation and in combination with other fertilizers. In crop rotations with vegetables and forage crops, all types of lime fertilizers are used; it is best to apply them in full dose at one time in the spring. In vegetable crop rotations, lime is applied directly under the cabbage or root crops.

When applying carbonic lime, it is necessary to combine liming with the use of manure and mineral fertilizers in crop rotation, and to apply boric fertilizers directly under root crops and potatoes, and on peaty soils - together with copper fertilizers.

It is especially important to apply increased doses of potassium fertilizers, since there is a certain antagonism of ions between calcium and potassium. With sufficient application of organic and mineral fertilizers, liming with full doses can also be carried out in crop rotations with potatoes.

In crop rotations with annual lupine or seradella for green fertilization, lime is applied when plowing these plants for fertilization.

On meadows and lawns, lime fertilizers are applied in a half dose superficially with harrowing in late autumn or early spring. With a radical improvement of meadows and lawns, a full dose of lime is used for plowing. Under the influence of lime, the number of acid-resistant grasses and weeds decreases, and the number of legumes increases, the growth and development of grasses improves, as a result of which the yield and nutritional value of hay is greatly increased, as well as the design of the lawn is improved.

9. Lime is spread on the soil first, creating the first and necessary contact of lime with the soil. Then mineral and organic fertilizers are scattered and then the fertilizers are mixed well with the soil by plowing or digging with the seam turnover.

10. Lime fertilizers should be dry and crumbly, in this case their effectiveness will be the highest.

11. Lime should be applied in dry and calm weather, so that the fertilizer does not swell during sowing and does not stick together from dampness.

We wish you success!