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Nitrogen deficiency: Nitrogen is the main component of protein and is the basis of plant life activities. In the absence of nitrogen in vegetables, the plants showed short stature, slow growth, short and thin stems, and many lignifications. The leaves are small; the leaves are greenish to yellow in color, gradually yellowing from the old leaves to the new leaves, the leaves are yellow at the base, and light brown after being dried. The knotted vegetables are not easy to be cricketed or have bad bulbs; the roots of the root vegetables are not easy to inflate. Cabbage such as cabbage, cauliflower and other nitrogen deficiency when the old leaves and stems will appear purple. Solanaceous fruit also showed problems such as flower and fruit growth retardation, abnormal precocity, low seeds, and low kernel weight. However, the symptoms of nitrogen deficiency are often similar to the effects of low temperature, and the low temperature of vegetables is also slower to absorb nitrogen, which is no different from nitrogen deficiency. Therefore, the nitrogen fertilizer needed for normal growth of vegetables must be supplemented in time, especially the common leafy vegetable fields.
Phosphorus deficiency: Phosphorus-deficiency symptoms are not as pronounced as nitrogen deficiency, and their common characteristics are slow growth, short plants, dark green leaves, and dull leaves, and the lower leaves turn purple or reddish-brown; less flowers, less fruit, late fruit ripening; poor lateral root growth The roots of root vegetables do not expand; fruits and vegetables are delayed and fruit ripening is delayed. Such as the lack of phosphorus in the pear, the leaves were dark green, potato chips become smaller, poor storage; tomato phosphorus red purple veins, common seedling period, some people think that is due to low temperature. In fact, tomato seedlings have very weak phosphorus absorption. Even if there is enough phosphorus in the soil, it will affect the absorption of phosphorus in case of low temperature, so low temperature is the direct cause of phosphorus deficiency in tomatoes.
Potassium deficiency: Potassium deficiency can cause the synthesis of carbohydrates in vegetables to be blocked, the cell wall becomes thinner, the texture becomes softer, it is easy to fall, and the ability to resist cold and drought is poor. Symptoms of the symptoms are yellowing of the tip and edges of the old leaves, and browning afterwards. Brown spots or patches often appear on the leaves. However, the leaf color near the middle of the leaf leaves often changes. In severe cases, the young leaves also show the same symptoms. Symptoms of leafy vegetables appear at the early stage of growth; for example, cabbage lacks potassium, and the edge of the outer leaves first turns yellow, then gradually extends inwards, and the leaf margins wither, but the symptoms often appear after the spherules. Symptoms of root vegetables appear when the roots are swollen; symptoms of the cabbage bulbs begin to appear at the beginning of the knots, and the leaves shrink and their hands feel hard; fruits and vegetables do not develop symptoms at the early stage of growth, but only when the fruit is enlarged. Leaves have symptoms.
Calcium deficiency: The plants lack calcium in the dwarf plant, the growing point shrinks, the apical buds die, and the growth stops; the young leaves curl, the leaf margins turn brown and gradually die; the root tip is dead, or even rot, and the fruit tip also has depressions and dark brown necrosis. Different vegetables have different symptoms. Typical symptoms of calcium deficiency in tomatoes and sweet peppers are umbilical rot. Cabbage, Cabbage Deficiency Calcium common leaf center leaves yellow, the typical symptom is marginal rot. There is a crack in the root of calcium in carrots. Burns appear on the top of calcium deficiency lettuce. Cucumber calcium deficiency at the top growth point necrosis and rot. Calcium-deficient vegetables often have high ground temperature, soil water shortage, and high concentration of soil solution, which causes calcium to be transported slowly in the plants. Therefore, vegetables should be supplemented with water during the drought period. Soils with low calcium content, high soil salinity, and excessive nitrogen fertilizers can affect the absorption of calcium caused by the roots, resulting in calcium deficiency.
Iron deficiency: Iron is one of the essential nutrients for the formation of chlorophyll. Plant iron deficiency produces iron deficiency chlorosis. From the tip of the new leaf, the disease manifests. The terminal buds and new leaves are yellow and white. They are initially chlorotic in the veins, leaving only reticulate green in the veins, and then all appear yellow-white. , but does not produce necrotic brown spots.
Boron deficiency: Boron is closely related to the reproductive process of vegetables. It can promote the germination of crop pollen and the growth of pollen tubes. Symptoms of boron deficiency appear at the stem and petiole, stem tip necrosis, and the leaves and petioles are fragile and easily broken. The stems, buds, and fleshy roots are discolored and necrotic in the pith, and the central part of the roots are black after breaking. Cabbage, celery petiole produce transverse cracks.
Zinc deficiency: Zinc affects the synthesis of auxin and is associated with photosynthesis and respiration. In the absence of zinc, the terminal buds do not die, the new leaves produce yellow spots, the lobuli are clustered, and the macula gradually expands to the entire leaf.
The method of identifying the deficiency of vegetables
Many people lack awareness of the lack of mineral elements in vegetables, and some treat the symptoms caused by a lack of nutrition as a disease. The symptoms of deficiency of several vegetables are described below.