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Nutrition on pistachio trees

 

In order to manage nutrition in pistachio orchards, we must know the important nutritional times during the pistachio growing season and be aware of choosing the right fertilizer and how to use it. Important nutritional times in pistachio include before flowering (bud swelling) in March and April, after flowering in April, fruit formation in May, growth and development of pistachio in June, pistachio kernel development in July The ripening and color change of the surface soft skin starts in August and the ripening of the product starts in September.
To determine the fertilizer requirement of pistachio trees in a scientific way, it is better to use the information and analysis results of pistachio soil, leaf and fruit analysis. Soil sampling can be done in all seasons from the shade area of ​​the tree and the analysis of the results should be done according to the irrigation method and soil texture and production potential in that area. Also, leaf sampling is usually done after the pistachio kernel is full, which provides a good basis for next year's fertilizer recommendations. General recommendations are also suggested based on research and nutritional feedback in pistachio, which can be a basis based on fertilization and using soil and leaf analysis, these recommendations can be changed in a specialized way.
Before making general recommendations for fertilizers in pistachio orchards, it is better to briefly review the importance of important and required elements in pistachio trees.

Important and required elements of Pistachio trees

Nitrogen element

Nitrogen is one of the main elements that depends on the growth and fruiting of pistachio trees. Nitrogen deficiency causes a decrease in growth, fertility and crop production. Pistachio trees do not absorb much nitrogen during hibernation. Therefore, nitrogen fertilization after harvest is not effective due to the beginning of the plant's dormant period and the slowing down of absorption power. It is better to use 30% less nitrogen fertilizers in low crop years than in high crop years. Considering the salinity of water and soil in pistachio growing areas, the type of fertilizers used should be aimed at adjusting the effects of bad salinity and the toxicity of sodium and chlorine ions. On the other hand, ammonium nitrate and ammonium sulfate fertilizers are more effective than urea chemical fertilizers for pistachio gardens. A decrease in the amount of nitrogen causes a decrease in the yield, a delay in leafing and flowering, a decrease in the length and diameter of the branches, reddening of the tree bark, small and yellowing of the leaves, reddening of the veins and petioles, and leaf fall before autumn, especially when the crop ripens in Fruit trees can be seen together or independently. Usually, in the case of nitrogen deficiency, the leaves at the bottom of the tree become lighter and smaller, and the number of leaves is reduced, or the growth of the crown of the tree is generally reduced. If the deficiency continues, the older leaves fall earlier than usual.

Symptoms of nitrogen deficiency in pistachio trees
Symptoms of nitrogen deficiency in pistachio trees

Phosphorus element

Phosphorus is one of the main and key elements in pistachio gardens, which is important in most physiological functions of the plant. The indiscriminate use of phosphorus fertilizers in the past decades and the incorrect method of surface spreading has caused the accumulation of phosphorus in the soil, while phosphorus fertilizers should be placed in the root development area and near the roots in order to have the necessary efficiency; For example, in fertile pistachio trees, the roots develop at a depth lower than 40 cm, and this place should be evaluated for the amount of phosphorus in the soil. In some areas, we are not facing a deficiency of phosphorus element in pistachios, but we are facing an excess of phosphorus, which prevents the absorption of zinc element. Characterization of burnt and non-uniform spots on the edge of old leaves, which eventually causes the leaf to dry as it spreads.

Signs of phosphorus deficiency in pistachio trees
Signs of phosphorus deficiency in pistachio trees

Potassium element

Potassium plays a key role in the production of proteins, enzymes, regulatory actions and water-plant communication. Potassium facilitates water infiltration in plant cells and controls the opening and closing of leaf openings during transpiration. The symptoms of potassium deficiency include the change of color of the leaves and the curling of their edges upwards. Also, the edge of the yarg is gray or copper in the folded part. Most of the leaves in question are located in the middle parts of the branches and as the growth continues, the branches become short, small and multi-sided. Since the need of the pistachio tree for potassium is the same as nitrogen (slightly more) and considering that potassium plays a very important role in the quantity and quality of the product, it should be given special attention. Potassium plays an important role in regulating the plant's water system, which is vital in dry areas and saline soils. Potassium fertilizers that contain chlorine and chlorine sources are only recommended in non-saline soils, so they are not suitable for the conditions of pistachio growing areas of Iran.

A sign of potassium deficiency in pistachio trees
A sign of potassium deficiency in pistachio trees

Calcium element

Calcium deficiency causes the leaflets to shrink and become spoon-like, and also causes the condition of bone skin spot. Factors that aggravate the lack of calcium include excessive irrigation water salinity, soil salinity and increased amounts of magnesium. The magnesium element prevents the absorption of calcium due to the mutual effect and the balance ratio between calcium and magnesium elements is very important. On the other hand, the use of chelate fertilizers of iron, zinc, manganese, etc. in the form of EDTA causes calcium deposition in plant organs and is also effective in calcium element deficiency. Calcium deficiency is very effective in revealing complications such as falling pistachio clusters and pistachio bone skin spots. Therefore, attention and timely use of this element will prevent the damage caused by these diseases.

A sign of calcium deficiency in pistachio trees
A sign of calcium deficiency in pistachio trees

Iron element

Iron is one of the essential elements in the plant, and for this reason iron deficiency is observed mostly in young or upper leaves. Iron deficiency in soil usually occurs due to its insolubility. Iron is completely soluble in acidic and moderately acidic soils. But in neutral or alkaline soils like most pistachio farming areas of Iran, iron is so insoluble that the plant cannot absorb it in sufficient quantity. The symptoms of iron (Fe) deficiency in pistachio trees are almost the same as most fruit trees, i.e. the leaves turn yellow and the main veins remain green. Although this yellowness is not visible in minor deficiencies, the overall color of the garden becomes yellow. One of the symptoms of deficiency is the appearance of burnt spots (necrosis) on the leaf surface. Usually, the crop of the deficient branches is not fully developed or withered. The number of seeds in the cluster is very small in this case.

Signs of iron deficiency in pistachio trees
Signs of iron deficiency in pistachio trees

Zinc element

Zinc plays an important role in pollination, fertilization and cell growth. In alkaline and sodium soils and areas with low rainfall like most pistachio farming areas, and in carbonate soils, the amount of absorbable zinc is very low, and in areas with light and sandy soil, a greater deficiency is observed. Deficiency symptoms, especially in severe cases, appear early in the season. The first effect of the deficiency is the delay in the opening of reproductive and vegetative buds of the pistachio tree. After the opening of the vegetative buds, the small and discolored terminal leaves (chlorosis) and the shrinking of the internodes appear as a collection of small leaves and brooms. As a result, the ability of the plant to photosynthesize and make chlorophyll is significantly reduced. Also, the pistachios on the tree or the zinc-deficient branches are clearly smaller and redder than normal pistachios.

Signs of zinc deficiency in pistachio trees
Signs of zinc deficiency in pistachio trees

Manganese element

Manganese deficiency is generally seen in the soils of dry areas and its poisoning occurs in acidic soils. Due to low mobility and dynamism of manganese element in plant tissues, deficiency symptoms can be seen in young leaves. The symptoms of manganese deficiency are similar to iron, with the difference that in manganese deficiency, a part of the green border remains.

A sign of manganese deficiency in pistachio trees
A sign of manganese deficiency in pistachio trees

Copper element

in gardens that have used animal and poultry manure for a long time or in sandy soils that have been irrigated with fresh water; The amount of copper in the leaves of trees is very low. Symptoms of copper deficiency in pistachio trees begin in late July to mid-August. In the deficiency of this element, the branches become stick-like and the color of their skin becomes dark. One of the symptoms of copper element deficiency compared to other micronutrient elements is the red cracking of the tree. To solve the lack of copper (Cu), it can be added to the soil with fertilizers containing it or sprinkled. In high concentration, copper also poisons the plant, the fruits become cracked and black, and small brown necrotic spots are observed on the leaves.

A sign of copper deficiency in pistachio trees
A sign of copper deficiency in pistachio trees

Boron element

Boron deficiency also occurs in young leaves, and its obvious symptoms are the complexity and unevenness of the leaf margins. In the case of boron deficiency, all the flower clusters fall off or the porosity of the product increases drastically. Boron poisoning or excessive boron can be seen in the pistachio growing areas, and the burning of the edges of the leaves is one of its symptoms. Deficiency is caused by the shortening of internodes on weak branches, the leaves are often twisted, misshapen, small, and in case of severe deficiency, it causes dead branches. Care must be taken when using fertilizers containing boron because a little extra boron can lead to poisoning of trees. Ber can be sprayed in combination with zinc at the time of bud swelling (before flowering).

A sign of boron deficiency in pistachio trees
A sign of boron deficiency in pistachio trees

Deductive diagnosis of some Complications and losses in Pistachio Garden

Sun burn pistachio
Sun burn
Lack of inoculation due to temperature fluctuations
Lack of inoculation due to temperature fluctuations
Pistachio drying due to temperature fluctuations
Pistachio drying due to temperature fluctuations
Salinity stress in pistachios and similarities with potassium deficiency
Salinity stress in pistachios and similarities with potassium deficiency
Molybdenum deficiency in pistachio trees
Molybdenum deficiency in pistachio trees
Sulfur deficiency in pistachio trees
Sulfur deficiency in pistachio trees

Management of animal fertilizers and high chemical consumption

Animal manures are important for improving the structure and texture of the soil, increasing water permeability in the soil, creating a balance in humidity and providing sufficient raw material and oxygen for soil microorganisms. Therefore, the consumption of animal fertilizers in the form of channel manure should be 20 tons per hectare on average. The consumption of nitrogen fertilizers should be divided and phased in the shade of pistachio trees. It is recommended to use it in 3 parts, in late March, late June and the last irrigation before harvesting. It is better to use phosphate fertilizers in the form of canal fertilizer in winter.

General nutritional advice for pistachio trees
  • Foliar of Sepehr 3 or zinc chelate fertilizer (in areas with more boron elements) and combining with liquid Super Micro fertilizer at the time of bud swelling (before flowering)
  • Foliar spraying of enriched iron chelate fertilizer after the petals fall (after flowering)
  • Super micro complete foliar spraying or special pistachio fertilizer at the beginning of fruit formation
  • Foliar spraying of complexed calcium fertilizer in early May and repeating it in 15 days
  • Foliar spraying of zinc chelate fertilizer in May
  • Foliar spraying of complex manganese fertilizer and copper chelate fertilizer in June
  • Foliar spraying and fertilizing with potassium fertilizer at the time of fruit and pistachio kernel thickening until the ripening stage
  • Foliar spraying with Sepehr 5 fertilizer (calcium+boron) or complex calcium fertilizer before harvest
  • Foliar of zinc chelate fertilizer after harvest
 

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