Symptom recognition and cause analysis of tomato deficiency

In the process of tomato planting, it is necessary to ensure adequate nutrition and comprehensiveness. If only a single nutrient is added, and the supplement of other trace elements is neglected, it is likely to cause symptoms of tomato deficiency. So what are the symptoms if the tomato lacks trace elements? How to find the missing nutrients corresponding to the symptoms?

Calcium

Increase the density of the peel and increase the thickness of the wax layer, thereby improving the surface light of the fruit and preventing the fruit from becoming aging. It is called "emission element" and is resistant to storage. At the same time, the fruit firmness is increased, the respiration intensity of the fruit is lowered, and the shelf life and storage period of the fruit are prolonged.

In the absence of calcium, the edges of the young leaves are light green, the back of the leaves is purple, the tips and leaves of the leaves are withered, the plants are thin, and the edges of the young leaves near the growth point are yellow and shrink, partially dead, and cause umbilical rot. Due to the poor mobility of calcium, it mainly accumulates in the old leaves, so the symptoms of calcium deficiency appear on the leaves.

It is determined that for every 1000 kg of tomato produced, it is necessary to absorb nitrogen (N) 2.4 kg, phosphorus (P2O5) 1.7 kg, potassium (K2O) 4.8 kg, calcium (CaO) 2.2 kg, and magnesium (MgO) 0.6 kg. In addition to nitrogen, phosphorus and potassium, the need for calcium in tomatoes is also very high, and attention should be paid to the supplement of calcium during the planting process.

The law of deficiency : insufficient calcium in the soil, excessive application of nitrogen fertilizer, excessive application of potassium fertilizer, high temperature and high humidity environment of the facility accelerates the absorption of calcium by vegetables, lack of soil calcium, and can not be replenished in time.

Calcium deficiency symptoms : cracking caused by calcium deficiency caused by calcium deficiency

2. Boron

Cell wall forming components, sugar metabolism and transport, flowering and fruit setting rate (pollen germination + pollen tube elongation)

Boron deficiency, leaves chlorotic or reddish, stem growth point dark, black, top branches and leaves curled, yellow and died, plants clustered, leaves easy to fall off. The stem is hollow or cracked, and it is easy to fall and fall. The fruit epidermis is corked, black patches appear on the surface, the fruit is easily deformed, and the fruit is easily cracked.

The law of deficiency : riverbed, gravel, sandy soil or red loam in rain-rich areas, due to long-term leaching, the boron content in the soil is extremely low, and tomatoes are prone to boron deficiency. On acidic sandy loam, excessive application of lime fertilizer at one time is prone to boron deficiency. In calcareous soils with high pH values, boron is easily fixed, has low effectiveness, and is prone to boron deficiency. The soil is dry, the movement of boron in the soil and the absorption of crops are blocked, and boron deficiency is prone to occur. The amount of soil organic fertilizer applied is small, and the field with high soil pH is also prone to boron deficiency. Excessive application of potassium fertilizer and nitrogen fertilizer will affect the absorption of boron by tomato, and it is prone to boron deficiency.

Symptoms of boron deficiency : Fruit deformation caused by boron deficiency, fruit cracking

3. Copper

Affect the metabolism of sugars and nitrogen. Lignin and melanin-forming enzyme activators

The copper-deficient plants became shorter, with clusters of branches, leaves curling, and plants wilting. The leaves are generally dark green or blue-green, the leaves are small, the leaf edges curl inward and upward, like a wilting appearance, the apex of the leaves is slightly chlorotic, browning and necrosis. Most of the symptoms occur in the upper leaves (young leaves).

The law of deficiency : The copper in the soil is difficult to move, and the clay and organic matter have a strong adsorption effect on copper. Therefore, copper deficiency is likely to occur on sticky and organic-rich soils.

4. Zinc

Zinc plays an important role in plants. Carbonic anhydrase is present in chlorophyll, which catalyzes the formation of carbonate and hydrogen from CO2 and water. The relationship between zinc and hydrogen is balanced. It can be seen that zinc is closely related to photosynthetic strength. Zinc is also related to the synthesis and stability of chlorophyll, which is yellowed in the middle of zinc deficiency. Zinc improves sugar metabolism and is related to the synthesis and transport of carbohydrates.

The central leaves of zinc deficiency began to fade, and the veins were clearly visible compared with healthy leaves; the leaves gradually changed from yellow to brown as the veins gradually faded; the leaves curled to the outside slightly due to the dead edge; the internodes near the growth point Shortening; zinc deficiency occurs in the middle and lower leaves, and the upper leaves generally do not yellow; zinc deficiency is caused by many factors. The leaching of strong sand has a low total zinc content and a low effective zinc content. It is easy to induce zinc deficiency when lime is applied. The soil and alluvial soils developed by the granite parent are sometimes low in zinc. The effectiveness of zinc in alkaline soil is low. Some organic soils such as humus soil and peat soil combine with organic matter to form a form that is not easily absorbed by crops. Excessive light, excessive phosphorus absorption, high soil pH, or low temperature, soil drought, slow release of zinc in the soil, tomato plants will be zinc deficiency due to insufficient supply of zinc. Furthermore, the application of phosphorus inhibits the absorption of zinc by plants.

The upper leaves become smaller and clustered, commonly known as "lobular disease". The middle and lower leaves are yellowed (to brown).

Remarks: Zinc deficiency is similar to potassium deficiency, and leaves are yellowed. Potassium deficiency is the first yellowing of the leaf margin, and gradually develops inward; while zinc deficiency, yellowing of whole leaves, gradually develop to the leaf margin. The difference between the two is that the order of yellowing is different.

5. Manganese

In the absence of manganese, the middle leaves or the old leaves are yellow, plaque-like, the young leaves are chlorotic, the reticular lines appear on the leaves, and finally the stems and leaves all turn yellow. Infertility buds, not flowering.

6.Mo

The tomato is deficient in molybdenum, the plant growth potential is poor, and the overall color is yellowish. Symptoms first appear on young leaves of plants. The young leaves are chlorotic, the leaf flesh between the leaf margin and the veins show yellow plaques, some of the yellow spots are dry, brown, irregular, and the diseased part is not obvious. Sometimes the leaf edge curls toward the inside and the tip of the leaf shrinks. Plants tend to bloom without result.

Pathogenesis : Molybdenum can improve the stability of chlorophyll and affect the synthesis and transportation of carbohydrates, so the lack of molybdenum leaves sometimes show yellow-green spots. In most cases, there is no shortage of molybdenum in the soil. The availability of aluminum in the soil is closely related to the acidity of the soil. When the soil conditions are acidic, the availability of available aluminum in the soil will decrease, resulting in the lack of molybdenum. . In addition, if the soil is deficient in phosphorus, sulfur deficiency, or the content of iron and manganese is too high, it will hinder the absorption of aluminum by plants.

Reasons for trace elements in crops:

1. Soil itself: The amount of trace elements in the soil is affected by the type of soil. Different types of soils have different parent materials, so they contain different trace elements.

2, the impact of pH: soil pH is an important factor affecting the effectiveness of trace elements. Tests have shown that when the pH is high, iron deficiency and zinc deficiency are caused; while in acidic soil, plants are prone to molybdenum deficiency.

3. Partial application of chemical fertilizer: Generally, partial application of nitrogen fertilizer will affect the absorption of calcium, so that the plant will show symptoms of calcium deficiency; partial application of potassium fertilizer will affect the absorption of boron by the plant, and the occurrence of boron deficiency; partial application of phosphate fertilizer may cause iron deficiency and zinc deficiency. Equivalent.

4, the application of medium and trace element foliar fertilizer is small: At present, the trace elements in vegetable fields are mainly supplemented by the application of organic fertilizer, while the amount of organic fertilizer is small, which further depletes the trace elements in the soil that is originally deficient. However, it was not sprayed with foliar fertilizer in time.

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