How to diagnose and control the deficiency of seedlings

Seedlings need a large amount of nitrogen, phosphorus, potassium, magnesium and other elements in the process of growth and development, but also need a small amount of iron, manganese, zinc, copper and other elements. When there is a lack of certain elements in the growth process, it will show the corresponding symptoms. In the growth period of the nursery, once there is a shortage of symptoms, as long as the symptomatic treatment, you can receive better control effect.

The growth of nitrogen deficiency is weak, the leaf color is light green, the base leaves yellow or light brown, the stems are long and thin, there are few tillers, the new leaves of the top shoots are smaller, the leaves are easy to fall off, and the roots are not well developed.

Phosphorus depletes cell formation, curls leaves, yellowish leaves, short plants, inhibits growth of young shoots and roots, affects carbohydrate, fat and protein synthesis, transport of organic matter in the body and growth of stems and roots, and small flowering The lack of color and light, poor fruit development, even withered and withered early.

Lack of potassium seedlings leaves shrinkage, the lower leaves susceptible to disease, branches and leaves weak, leaves and leaves often withered, the lower leaves easy to fall off, slender stems, severe when the leaf margin scorch, old leaf edge curl yellow or fire color And easy to fall off.

Calcium deficiency will cause the seedling roots to be stunted, the top buds to suffer, the stems and leaves to be weak, the leaf margins curled and coke up, showing white stripes, and the tips of the leaves are hooked. When the calcium deficiency is severe, the whole plant will die.

Iron deficiency first fades green from the new leaves and veins, and the veins are still green. Finally, the veins turn green, and the entire leaves turn white from yellow. Generally no withering occurs. If the nursery suffers from iron deficiency for a long time, the tips of leaves and leaves will gradually wither and expand inwards, but the large leaves will remain green.

Magnesium-deficient old leaf veins are the first to lose chlorosis, severe necrotic spots appear, and tip and leaf margin curl upwards, and the leaves are spoon-shaped, with yellow streak, shrinkage, late leaves often withering, and small leaves leading to small, pale flowers. Plant growth is inhibited.

Boron deficiency often leaves chlorosis, leaf hypertrophy shrinking, leaf margin curling upwards, underdeveloped seedling root systems, terminal buds and young roots growth point of death, falling flowers and falling fruit.

The zinc-deficient seedlings show marked atrophy and ossification between the nodes, yellowing of the leaves, yellow spots between veins, spreading to new leaves, young leaves hard and small, and yellowish white.

Copper seedlings have white tips, young leaves shrink, and white leaf spots appear.

For yellow leaves, if the lower yellow leaves are mostly lack of nitrogen, potassium, magnesium, zinc, the lesions on the leaves of the old leaves are mostly potassium, magnesium, zinc, and the lesions are considered as nitrogen deficiency. The upper new leaves yellow, mostly iron deficiency, sulfur, manganese, boron and other symptoms. Most of the apical buds were found to be due to lack of boron or calcium deficiency.

The flowers and plants in the nursery are different in sensitivity to the lack of the same element, and because there are often similarities in many deficiency symptoms, the morphological symptoms can only be used as a new diagnosis. The following two methods can help diagnose the disease.

One is to take a small finger-shaped glass tube containing the test solution and bind it to the diseased strain. Then, the leaves on both sides of the main vein of the leaf were cut off and the main vein was immersed in the glass tube solution. If the tested strain returned to normal after 7 days to 10 days, the missing elements of the seedling could be confirmed.

The second is to determine what kind of elements may be lacking from the symptoms of nutrient deficiency in seedlings, then use this element fertilizer to make up a certain concentration of solution, use a brush to paint on the back of the lighter leaf, or spray on the diseased plants, 7 days to After 10 days, the recovery of the condition was observed. If the disease condition improves, or if the growth rate of new leaves is significantly increased and the leaf color is normal, it can be confirmed that seedlings lack the kind of elements sprayed or applied.

Seedlings have symptoms of nutrient deficiency, mainly because the nursery soil is too acidic or over-alkaline, which affects the dissolution and release of certain elements; or the underutilization of base fertilizers, especially the neglect of the use of decomposed organic fertilizers, if the physical and chemical properties of the soil are not good, It will significantly affect the supply of fertilizer; or in the nursery will only use a large number of elemental fertilizers such as nitrogen, phosphorus and potassium, which will prevent the seedlings of the absorption of trace elements, resulting in seedlings due to lack of trace elements of the lack of symptoms.

To prevent the emergence of nutrients in nursery stocks, the best way is to configure nutritious soil so that all kinds of nutrients are complete. If nutrient soil seedlings cannot be used in large quantities, organic fertilizers such as cake fertilizers and various cooked manures should be used. During the growth period, seedlings can be sprayed with a full-component compound fertilizer at a concentration of 0.1% to 0.3%, or sprayed with Huimanfeng and other active liquid fertilizers at a concentration of 1:500 to 1:800. Once the symptoms of deficiency are confirmed, the corresponding trace element fertilizers can be sprayed correspondingly, such as foliar spraying of 0.05% to 0.1% of ferrous sulfate solution in the event of iron deficiency; 0.2% to 0.4% of magnesium sulfate solution in the absence of magnesium. Calcium deficiency spraying 0.2% to 0.4% lime water, etc., can receive the effect of symptomatic treatment.