In the process of growth and development of tomato, it is necessary to absorb a variety of nutrients. When a certain element is lacking, it will show a corresponding lack of symptoms on the external morphology, which will affect the yield and quality of tomato.
First, the lack of symptoms
1. Nitrogen deficiency. In the absence of nitrogen in tomato, the plants are thin, the leaves are light green or yellow-green, the leaves are small and thin, the veins change from yellow-green to deep purple, and the stems become hard and dark purple. Buds turn yellow, easy to fall off, small and small fruit.
2. Phosphorus deficiency. In the absence of P in tomato, purple leaves appeared on the back of the early leaves, and some small spots first appeared among the veins. Then they spread to the entire leaves, and the veins and petioles finally turned purple. The stems are slender, full of fibers, and the leaves are small, with leaf curling later and fertility delayed.
3. Potassium deficiency. When tomato lacks potassium, the old leaves and lobule are burning-like, leaf margins are curled, veins are chlorosis, and some will have brown spots on the chlorotic area. After that, the old leaves fall off and the stems become thicker and lignified. The roots are weak and the fruits are not mature and deformed.
4. Calcium deficiency. Tomato requires large amounts of calcium, flowering calcium deficiency can occur top cracking fruit, young fruit and around the umbilical skin cracking, placental tissue valgus, so that the young fruit formed seven transversal fissure malformation. Calcium deficiency during the expansion of young fruit can form umbilical rot fruit, commonly known as “black plaster diseaseâ€. In the early stage of disease, yellow-brown spots appear near the umbilicus, which turn brown as the lesion expands, becomes inwardly dent, hardens, and the fruit stops expanding. Early reddening, fruit shape becomes flat, fruit surface less shiny.
5. Mg deficiency. The new leaves curl, the middle and lower leaves are generally yellow and develop from bottom to top. When tomato lacks magnesium, the chlorophyll content is low, the leaves are yellow, and the photosynthesis is weak, which seriously affects the accumulation of nutrients, which can cause a significant reduction in production.
6. Manganese deficiency. When the tomato is deficient in manganese, the veins in the leaves are chlorosis, and the yellow leaves are located farther from the main vein and the veins remain green. Afterwards, there are spotted leaves on the leaves, and finally the leaves turn yellow. In many cases, brown spots appear before the appearance of the macula. In severe cases, growth is inhibited, and flowers do not bloom and are not strong.
7. Boron deficiency. Seedlings and true leaves of the seedlings are purple, and the leaves are stiff and brittle. Stems grew black and dry, and new lateral branches grew near the growing point. The whole plant is clustered. The branches at the top curl inward, yellow and die, and the leaves, petioles, and midribs become brittle. The fruit is not ripe at maturity, and the fruit often covers some dark black scars and breaks.
8. Sulfur deficiency. The leaves are pale green and curled upwards. The plants are pale green or yellow-green, with dead or dead hearts.
Second, control methods
In combination with the symptoms of tomato deficiency, apply appropriate amount of fertilizer. In addition to the full amount of the end application, if there is a lack of symptoms can be combined with watering topdressing or foliar spray. Foliar spray concentration should be appropriate, spraying once every 5 days, 2 or 3 times in a row.
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