Potash fertilizers

Unlike nitrogen, which is readily available to plants, there is little potassium in organic matter. Is that ash is the supplier of this battery. But to replenish the reserves of potassium needed to grow only food plants, it needs so much that it would have to burn all the forests. However, in nature there are deposits of ores rich in potassium. They are the raw material for the production of potash fertilizers.

What is potash fertilizer

Potash fertilizers are a mineral source of potassium, an essential nutrient for plants. In each fertilizer, the amount of potassium is different, but this element always prevails.

In the soils of our country, there is always a lack of potassium, part of it is carried out by plants, so potash fertilizers are the most popular both in agriculture and among summer residents. And most importantly, potassium in them is in an accessible form.

Importance of potash fertilizers

Potash fertilizers are especially in demand on sandy, peaty, podzolic and calcareous soils. Thanks to their use, the yield increases by 30 – 40%.

Fertilizers containing potassium contribute to the development of green mass of plants and active flowering, increase resistance to diseases and pests.

Complete potassium nutrition contributes to:

• activation of the processes of formation of enzymes and photosynthesis;
• improving the quality of flowering and fruit set;
• an increase in the content of starch and sugar;
• improving the taste of fruits and increasing their shelf life;
• increase frost resistance and drought resistance.

Grapes, potatoes, cucumbers, tomatoes and beets are especially in need of a complete potassium nutrition.

An important property of potash fertilizers is that they are water-soluble and are well absorbed by plants. Valuable qualities include the ability to combine with other mineral elements. At the same time, the action of each is enhanced (1). However, there are also disadvantages – potash fertilizers quickly cake at high humidity and become unusable.

Types and names of potash fertilizers

Many gardeners believe that to replenish potassium in the soil, it is enough to use wood ash, which is obtained from the burning of tree species and straw. However, it does not always give a positive result, especially in situations where traces of potassium deficiency are clearly visible on plants – ash cannot replenish it quickly.

Garden centers offer a range of effective potash fertilizers to help maintain soil fertility.

Potassium sulphate (potassium sulphate)

Its formula is K₂SO₄. It is a crystalline fertilizer with a high content of potassium (up to 50%), which also contains sulfur, calcium and magnesium. Does not cake, dissolves well in water. It does not contain chlorine, so the fertilizer is effectively used at any time of the year on almost all types of soils, except for acidic ones.

Fertilizer is recommended for almost all vegetable crops, it is especially effective for cabbage family crops and root crops.

Restriction: Do not mix with lime additives and manure.

Potassium nitrate

Formula – KNO₃. It is a universal growth stimulant for all plants, since in addition to potassium (38%) it contains up to 13% nitrogen. It is most effective when applied in the spring before planting and as a root dressing in the summer.

It is recommended for all plants, taking into account that nitrogen is poorly absorbed on acidic soils, and potassium is not absorbed on alkaline soils.

Restrictions: it is not effective to apply in the fall; if stored improperly, it becomes caked and cannot be used.

Potassium chloride

The chemical formula is KCl. Refers to concentrated fertilizers containing up to 60% potassium and up to 40% chlorine. It is mainly used in autumn in soil preparation, which allows reducing the chlorine content in the soil by the time of spring planting.

Recommended for all types of horticultural and horticultural crops, for almost all types of soil, except acidic.

Limitations: High chlorine content acidifies the soil.

Calimagnesia

Formula — K₂SO₄•MgSO₄. Multi-component potash fertilizer containing up to 30% potassium, up to 10% magnesium and 17% sulfur. Despite the fact that the fertilizer contains a small amount of chlorine (no more than 1,5%), it is considered chlorine-free.

Recommended for all types of soils, except for chernozems and solonetzes. Apply on light soils in spring, and on heavy soils in autumn.

Limitations: Exceeding the dosage degrades the quality of the soil.

Wood Ash

A complex mineral fertilizer of a natural type containing potassium, calcium, iron, copper, magnesium and most other trace elements. Widely used in private farms and summer cottages.

It is recommended for growing all types of plants, except acidophiles (plants that love acidic soil), on all types of soil, except alkaline, that is, the ash alkalizes the soil.

Restrictions: Do not mix with nitrogen fertilizers and superphosphate, apply simultaneously with manure and bird droppings.

The use of potash fertilizers

It is important to use fertilizers containing nitrogen and phosphorus simultaneously with potash fertilizers – in this combination, each nutrient becomes the most effective.

Potash fertilizers are mainly used in the fall when preparing the soil. Due to this, potassium enters the lower layers of the soil and becomes available for perennial plants.

However, on soils poor in potassium, and under potassium-loving plants, fertilizers can also be applied in the spring when preparing the soil for sowing – directly into the planting holes or rows. During rains and when watering, potash fertilizers dissolve and nourish the plants.

In summer, if there are signs of potassium deficiency, foliar and root top dressing with potassium fertilizer solutions is recommended. The optimal time is budding and the beginning of fruit ripening (2).

Pros and cons of potash fertilizers

Like any other fertilizer, potash has its pros and cons.

The pluses include:

• most fruit and ornamental crops easily absorb potash fertilizers;
• with rare exceptions, they are compatible with other mineral fertilizers;
• strengthen the immune system of plants, as a result of which they get sick less and more easily tolerate adverse weather conditions, including cold winters;
• reduce the adverse effects of insect pests.

But there is only one minus for potash fertilizers: an excess of such dressings leads to a slowdown in the development of plants and their drying out.

However, one should carefully consider the selection of one or another potash fertilizer depending on the type of soil, compatibility with other fertilizers and the ratio of plants to chlorine (3).

The use of potash fertilizers in the garden and vegetable garden

Plants always tell us what element of nutrition they lack. If there is a deficiency of potassium, the leaves begin to turn yellow, dry out from the edges until they turn brown and die completely. Spots and numerous wrinkles appear on the leaves, the stems become thinner and the plant practically stops developing.

At the first signs of potassium deficiency in the summer, additional plant nutrition is carried out. For this, aqueous solutions are most often used for irrigation under the root or foliar top dressing. On soils poor in potassium, such top dressing is carried out during the flowering period, as well as at the initial stage of fruiting.

In summer, it is recommended to carry out top dressing, taking into account weather conditions: on rainy days, dry fertilizers are better absorbed, in dry weather, aqueous solutions should be used.

However, the main application of potash fertilizers is carried out in autumn or spring.

Autumn top dressing is the main one. In this case, dry fertilizers are applied when digging the site. And also when planting trees and shrubs – in a pit. This method allows plants to obtain available potassium throughout the growing season. It is especially important to apply fertilizers containing chlorine in the fall so that this harmful element is neutralized as much as possible by the beginning of the growing season.

In the spring, potash fertilizers are most rationally applied precisely – in planting holes and grooves.

The application rates for potash fertilizers are clearly spelled out in the instructions for each type. And they should be strictly observed, since a decrease in dosage reduces the effectiveness of top dressing, and an increase can cause an excess of potassium in the soil. What will negatively affect plants (3).

The basic norms for applying potash fertilizers are as follows:

• potassium chloride – from 20 to 40 g per 1 sq. m;
• potassium nitrate – from 20 g per 1 sq. m;
• potassium sulfate – from 10 to 15 g per sq. m;
• potassium magnesia – from 20 g per 1 sq. m.

Gardeners use potash fertilizers in the following cases:

• when growing cucumbers – liquid top dressing under the root with potassium sulfate at the rate of 40 – 45 g per 10 l of water;
• when growing tomatoes – potassium sulfate when planting or potassium chloride when preparing the soil at the rate of 50 g per 1 sq. m;
• when growing onions – 5-6 days before planting, the bed is watered with a solution of potassium chloride at the rate of 20 g per 10 liters of water;
• when growing cabbage – in the planting holes, 1,5 – 2 liters of an aqueous solution of potassium sulfate (20 g per 10 liters of water), and at the beginning of the formation of a head of cabbage, a pinch of potassium magnesia is added under the plant;
• when growing potatoes – in the fall for digging or in the spring when preparing the soil 15 – 20 g of potassium chloride or 35 g of potassium sulfate per 1 sq. m.;
• when growing grapes – 3 foliar top dressing with potassium magnesia solution at the rate of 20 g per 10 l of water.
• when growing tree species and flowers – at the beginning of flowering, top dressing is carried out under the root with potassium nitrate at the rate of 20 g per 1 sq. m.

Popular questions and answers

We addressed the most important questions about potash fertilizers agronomist Oleg Ispolatov.

Sources of

1. Kovalev N.D., Atroshenko M.D., Deconnor A.V., Litvinenko A.N. Fundamentals of agriculture and crop production // M .: Selkhozizdat, 1963 – 567 p.

2. Osipov A.I. The role of fertilizers in soil fertility and plant nutritionhttps://cyberleninka.ru/article/n/rol-udobreniy-v-plodorodii-pochv-i-pitanii-rasteniy

3. Pchelkin V.U. Soil potassium and potash fertilizers // M .: Kolos, 1966