Pear

It is differently represented in certain organs and tissues. Leaves, flower buds, fruits and seeds have the most nitrogen. The role of nitrogen in the life of apple and pear trees is multiple. The beneficial effect of nitrogen is reflected in the increase of photosynthesis, growth of leaves, shoots, fruits and other organs of fruit trees and in the increase of flower buds. Nitrogen affects the overall development of the fruit, especially the abundance and quality of growth.

Nitrogen deficiency is reflected in reduced growth of young shoots, smaller leaves, reduced germination of flower buds, weaker flowering, increased decline of already germinated fruits and generally weaker fruit development. In general, whole trees remain less developed, stunted and decay faster. However, excess nitrogen can also have an adverse effect on apple and pear trees. The form of nitrogen applied may also have an impact on the trees. Excessive application of nitrates may lead to an increase in plant redox potential, which could lead to crop health issues.

If the soil is too rich in nitrogen, then the young shoots, leaves and roots grow very abundantly. Growth continues until late autumn, the young do not ripen enough but remain with green and soft tissue, so they freeze easily. At the same time, sensitivity to diseases and pests increases, and some physiological changes occur. Due to the excess of nitrogen, the ripening time of fruits is prolonged, and their duration is shortened. One of the most important issues resulting from an excess of nitrogen can be the imbalance with K, Ca and
Mg and the subsequent increase in the incidence of bitter pit. Timely application of nitrogen fertilizers to the soil is also very important. Too late application of nitrogen fertilizers causes prolonged vegetation. On the other hand, nitrogen fertilizers are easily soluble and mobile, so there are bigger losses if everything is applied in the fall, because there is usually a lot of precipitation in the fall and winter.

Due to the intensive growth of roots in the fall, which requires a lot of nitrogen, it is important to apply nitrogen fertilizers in the fall , before the risk of frost. In the spring, intensive root growth begins again, followed by flowering, fertilization, growth of young shoots and fruits, and a lot of nitrogen is needed for the growth of these organs. So, it should be fertilized with nitrogen in the spring as well. At the beginning of the summer, flower buds are planted for the next year, young shoots and fruits grow profusely, so again a lot of nitrogen is needed.

It is important to apply phosphorus in the right form and at the right time: in case of the need to improve the color of the fruit, foliar application is very effective after flowering and at early maturity. If this element is missing, the fruits will be spongy, and its excess can affect the amount of zinc. Phosphorus is an essential nutrient both as a component of several key plant structures and as a catalyst in numerous key biochemical reactions in plants. Phosphorus is a vital component of adenosine triphosphate (ATP), the “energy unit” of plants. ATP forms during photosynthesis, has phosphorus in its structure, and is active from the beginning of seedling growth through to the formation of fruits and maturity. Phosphorus is important for the general health and vigour of all plants. Some specific growth benefit that have been associated with phosphorus are: a stimulation of root development, increased branch strength, improved flower formation and fruit production, more uniform and earlier ripening, improved crop quality, increased resistance to disease, and more vigorous development throughout the growth cycle.

Phosphorus is an essential nutrient for all parts of the tree as it is required for membranes, energy molecules and nucleic acids. In cases of phosphorus deficiency, the fruit are more highly colored and ripen earlier but exhibit surface defects and poor flavor. Phosphorus is not always fully available, so it is very important to have a soil phosphorus analysis and to adapt the phosphorus fertilization accordingly. Growers should also take into account that phosphorus can be immobilized in calcareous soils or acidic soils containing iron. Compared to nitrogen and potassium, phosphorus deficiency in apples and pears is difficult to diagnose. Some of the symptoms include poor root growth and stunned growth of the trees, purple coloration of leaves, reduced flowering and seed formation and fruit set, reduced leaf and shoot growth, reduced fruit size and lesser fruit color and delayed fruit maturity.

Potassium also helps to promote the storage of reserves in different parts of the plant and hence it is important to apply adequate amounts of this element during the autumn. Potassium plays a role in orchard vigor and yield, and it contributes to the neutralization of formed organic acids. It also promotes respiration and activates growth. This is an important health factor for trees because it facilitates the proper distribution of reserves between different parts of the tree. It intervenes in the regulation of the opening and closing of stomata, it plays a role in improving drought resistance via better water use efficiency, ensuring an improvement in the
functioning of the stomata.

Potassium promotes the setting and advances the maturation of the fruits. In addition, it helps protect against frost. Potassium deficiency causes the appearance of small leaves, narrow and yellowish green, which is later dark (reddish-brown) along the rim, wrinkled in the middle. The dried part of the leaf is twisted towards the face of the leaf, and then it curls and falls off. Extinction starts from the top. The fruits are smaller, less colored and with less sugar. The flesh of the fruit is spongy or woody. Resistance to frost, diseases and pests is reduced.

In the tree, it is incorporated into certain amino acids (cysteine, methionine) and subsequently becomes part of all enzymes and proteins and certain vitamins and oils. Once in these complex molecules, sulfur is not easily mobilized within the plant. Deficiency symptoms, therefore, will occur in the young tissues first. Senescing leaves efficiently retrieve sulfur. As complex molecules are broken down, sulfur is converted into sulfate (SO₄ ^2-), which is readily transported out of the leaf and into the rest of the plant.
All proteins (and therefore enzymes) need sulfur to function, as disulfides bonds stabilize their structures. Sulphur also plays a key role in nitrogen metabolism. Sulfur plays a role in the aroma of certain fruits through
volatile sulfur compounds.

Calcium (Ca) is an important element in pome tree fertilization and is directly related to fruit quality. In cases where insufficient calcium (Ca) is supplied, there is a higher risk of bitter spots (Bitter Pit) appearing in apples and cork spots in pears. The correct supply of calcium will reduce the their incidence. There are many reasons for the appearance of bitter pit, and in modern pome growing it is necessary to consider all the factors that limit the absorption of calcium. Proper fertilization and selection of calcium-based fertilizers can significantly reduce the appearance of bitter pit in apples. Cork spot is one of the most damaging physiological disorders in pear. However, the mechanism of cork spot is unclear. Calcium deficiency is considered as the major factor leading to cork spot. In some studies, it has been found that pears located in lower half of the tree crowns showed a significantly higher calcium concentration resulting in lower K:Ca ratio than those from the upper half. On the other hand, pears with cork spot show a significantly higher potassium and magnesium and significantly lower calcium content. Calcium uptake takes place passively in the form of Ca2+ions via the root tips. The uptake depends on the root growth, soil temperature, soil moisture content and soil texture. Most of the annual amount of calcium required by the tree is taken up from the soil and, whilst only a relatively small amount originates from reserves in the wood this part is vital for healthy tree growth. The fruits are mainly supplied with calcium during the cell division phase, in other words during the first six weeks after blossoming. Adequate amounts of potassium are key for efficient calcium uptake. For calcium fertilizer applied to the soil uptake via the roots is stimulated by a moist soil and by sufficiently high transpiration and is negatively influenced by a dry, cold soil. Calcium is also very important for optimal nitrogen use efficiency.

The transport of calcium over large distances in the tree takes place almost exclusively via the xylem vessels, i.e. in the transpiration flow. As their transpiration rate is much higher (ratio 1:10), leaves are supplied far better with calcium than the fruits. Due to the poor mobility of calcium in the phloem vessels no calcium travels from the leaves to the fruits. Transport over short distances from cell to cell is driven by a so-called ‘auxin pump’ mechanism. The auxin producing tissues in the plant have a hormonal sink effect and therefore have priority in the supply of nutrients and water. This mainly concerns young leaves found in the shoot tips and close to the fruits (rosette leaves) and the flowers and seeds in young fruits. Trees that blossom well and exhibit a good fruit set and healthy, well developing leaves absorb more calcium in total than trees that flower badly which have low production and poor leaf quality. To a certain extent shoot growth is useful in supplying the entire plant and so the fruits, too, with calcium via the transpiration flow.

In the summer the young leaves, compete directly with the fruit close to the shoots for the supply of calcium. If growth is too strong and too prolonged, this may cause calcium to be diverted from the fruits in favour of the shoot tips. Even and balanced growth and production and halting growth at an early stage are the most important aspects in creating a good distribution of calcium throughout the tree.

Magnesium is mobile in plants, so the symptoms of deficiency appear on the lower leaves during the intensive growth of fruits.

Inadequate levels of magnesium cause a yellowing of tissue along leaf margins and between the main veins. Symptoms may initially develop along leaf margins, similar to potassium deficiency symptoms. As the deficiency progresses, the yellow regions turn brown and die, leaving a Christmas tree-shaped green area along the main veins in the middle of the leaf.

Magnesium deficiency can occur with light, acidic soils that are prone to leaching or in soils that have received high rates of potassium fertilizers.

Each litre of Thio-Sul provides approximately 160 g of nitrogen and 346 g of sulfur, delivering a concentrated and efficient source of both nutrients. Its liquid formulation is easy to handle and integrates readily into modern crop nutrition programmes across a wide range of crops and production systems.

By supplying nitrogen and thiosulfate sulfur together, Thio-Sul helps maintain an appropriate nitrogen-to-sulfur balance, supports protein formation and promotes more efficient use of applied nitrogen. Its sulfur becomes available progressively as thiosulfate is converted in the soil, helping support crop nutrition throughout key growth stages.

Thio-Sul can be applied through irrigation systems, banded, broadcast, injected into the soil or incorporated into compatible liquid fertiliser blends. This application flexibility makes it a practical solution for improving sulfur nutrition and complementing nitrogen fertilisation.

Each litre of KTS supplies approximately 360 g of potash and 252 g of sulfur, providing a highly concentrated source of soluble potassium and sulfur. Its nitrate-free and chloride-free formulation allows potassium to be supplied without adding unnecessary nitrogen or chloride.

Potassium supports water regulation, enzyme activity, carbohydrate transport and the development of crop yield and quality, while sulfur contributes to protein and enzyme formation. KTS is particularly valuable during periods of rapid growth, reproductive development and crop filling, when potassium requirements can increase substantially.

KTS can be used through fertigation, in starter or side-dress programmes, in compatible liquid fertiliser blends and as a foliar treatment on selected crops. Its versatility allows potassium and sulfur to be delivered at critical stages within a wide range of crop nutrition programmes.

Each litre of CaTs supplies approximately 75 g of calcium and 125 g of sulfur, providing both nutrients in a fully soluble liquid form. CaTs combines crop nutrition with soil-management benefits and can be incorporated into a broad range of fertilisation programmes.

Calcium contributes to cell-wall strength, root development and the structural integrity of growing plant tissues, while sulfur supports protein and enzyme formation. A consistent calcium supply is especially important during periods of rapid vegetative growth and fruit development, helping support crop quality, firmness and marketability.

CaTs can be applied through irrigation systems, banded, broadcast or blended with compatible liquid fertilisers. It may also be used as a soil amendment to provide soluble calcium, support soil aggregation and water infiltration, and help manage the effects of excess sodium in saline or sodic soils.

Its fine crystalline formulation dissolves rapidly and completely, producing a clean spray solution with minimal residue. This makes K-Leaf particularly suitable for precision spraying and for situations in which crops require a rapid supplementary supply of potassium and sulfur.

Applied directly to the foliage, K-Leaf helps prevent or correct potassium and sulfur deficiencies during critical growth stages. Potassium supports water regulation, photosynthesis, carbohydrate movement and crop quality, while sulfur contributes to protein synthesis and essential metabolic processes.

K-Leaf can supplement soil fertilisation when nutrient uptake through the roots is restricted or when crop demand temporarily exceeds soil supply. It is suitable for a wide range of broad-acre, fruit and vegetable crops and can be combined with many compatible soluble fertilisers and crop-protection products following a compatibility test.

SoluPotasse provides potassium and sulfur without nitrogen or chloride, allowing both nutrients to be managed independently within the crop nutrition programme. Its fine crystalline form dissolves rapidly and completely, making it suitable for demanding fertigation applications.

Potassium supports water-use regulation, enzyme activation, carbohydrate transport and crop quality, while sulfur contributes to protein formation and nutrient metabolism. SoluPotasse is particularly useful when crops require additional potassium but no further nitrogen, including during fruit, tuber and grain development.

SoluPotasse can be applied through fertigation and other systems designed for fully soluble fertilisers. Its low-chloride, nitrogen-free composition makes it well suited to chloride-sensitive crops, saline growing conditions and fertilisation programmes requiring precise control of nitrogen and potassium inputs.

The chloride-free, nitrogen-free formulation of GranuPotasse provides an efficient source of potassium and sulfur, making it ideal for chloride-sensitive crops and high-value production systems. The uniform, free-flowing granules ensure accurate spreading, easy handling and consistent field performance.

By supplying potassium and sulfur in readily available forms, GranuPotasse supports water regulation, enzyme activation, carbohydrate transport and protein synthesis, helping improve crop yield, quality and marketability. It is particularly beneficial for fruit, vegetable and other high-value crops where crop quality, storage life and export potential are essential.

GranuPotasse® is suitable for pre-plant, basal and in-season applications and can be broadcast, banded or incorporated into the soil. It also blends readily with many granular fertilizers, providing growers with a flexible solution for balanced potassium and sulfur nutrition across a wide range of cropping systems.