First, the symptoms of phosphorus deficiency in vegetables
In the early stage, the old leaves are dark green, dull or purplish red. Starting from the lower leaves, the leaf edges gradually turn yellow and then die and fall off. When some vegetables are deficient in phosphorus, the lower leaves and stem base are purple-red, which is more obvious at seedling stage. In the middle and late period, there is some relief. When the phosphorus is seriously deficient, the leaves die and fall off. The stems are small and woody. Root and root hair length increase, root radius decreases, secondary roots are rare, some vegetables can secrete organic acids when phosphorus is deficient, so that rhizosphere soil acidifies, dissolves more insoluble phosphorus, and improves soil phosphorus availability. Phosphorus easily causes the relative growth rate of roots to increase, and the ratio of root to shoot increases, thereby increasing the absorption and utilization of phosphorus by roots. Less flowers, less fruit, late fruit, seeds are not full, and thousands of grains are reduced. Phosphorus deficiency can also cause the accumulation of nitrates in vegetables, resulting in a decline in quality. The symptoms of phosphorus deficiency in several vegetables are as follows:
1. The growth of phosphorus deficiency in Chinese cabbage is not strong. The plants are dwarfed and the leaves are small and dark green. The stems are fine and the roots are weak.
2. The phosphorus-deficient leaves of eggplant are dark purple, the stems are slender and the fibers are developed. Flower bud differentiation is delayed and firm.
3, radish deficiency of phosphorus leaves back red purple, root system dysplasia, plant growth is short, leaves small and shrinking.
4. The early leaf back of tomato is reddish purple. The mesophyll tissue is spotted and then spreads throughout the leaf, the veins gradually turn reddish purple, and the leaf clusters are finally purple. The stem is slender and rich in fiber. The leaves are small, the plants are short, the old leaves are yellow, and there are purple spots. They fall off before the fruit matures, and the results are delayed.
5, cucumber lack of phosphorus leaf color dark green, with the increase of leaf age, the color is more dim, gradually brown and dry. The plants are short and thin. Browning and necrosis between veins. The number of female flowers is reduced. Fruit deformity, dark copper green.
6. Phosphorus deficiency on onions grows slowly in the late growth stage, and the old leaves are dry or the tips of the leaves die. Sometimes the leaves have yellow-green and brown-green spots.
7. The lettuce lacks phosphorus leaves dark green, reddish brown or purple, the old leaves die, the growth is short, the leaf ball is poorly formed, the ball is late, and the top of the stem is rosette-like.
8, celery lack of phosphorus leaves dark purple, petiole small, root dysplasia, plants stay in the leaf cluster growth period.
9, carrots lack of phosphorus leaf color dark green with purple, old leaves die, petiole grow up.
10. The cabbage leaf lacks phosphorus and is small and hard, and the leaf edge is dead.
Second, excessive phosphorus application symptoms of vegetables
Excessive phosphorus, plant leaves are thick and dense, the leaves are dark green, there are many small plants, the cellulose content of leafy vegetables is increased, the eating quality is reduced, and the uniformity is poor. Due to the early maturity of the reproductive organs, the vegetative body is small, the growth of stems and leaves is inhibited, and the plants are prematurely fading. The root system is developed, and the number of roots is extremely large and extremely short. A condition caused by excessive phosphorus is usually manifested by chlorosis such as zinc deficiency, magnesium deficiency, and iron deficiency. The legume crops have low protein content and are prone to cause deficiency of zinc, iron, manganese and wow, and the harvest time is inconsistent.
3. Phosphate fertilizer types and application methods suitable for vegetables
1. Superphosphate is abbreviated as calcium phosphate and is a water-soluble phosphate fertilizer. The content of phosphorus pentoxide is 12-20%, which is a loose powder or granule such as dark gray, grayish white or light yellow. Acidic and corrosive. Stored under humid conditions, it will be converted into insoluble iron phosphate and aluminum sulfate after moisture absorption, reducing the effectiveness of the fertilizer. Therefore, it should be protected from moisture and the storage time should not be too long. Calcium superphosphate also provides calcium and sulfur, which account for 12% and 9% of the total weight of the fertilizer, respectively. It can be widely applied to various soils and crops, especially suitable for alkaline soils or soils lacking sulfur and calcium, and crops requiring more calcium and sulfur. (1) Centralized application: It can be used as base fertilizer, seed fertilizer and top dressing, and the effect of base fertilizer and seed fertilizer is better. When using the base fertilizer, ditch or open the hole and apply the fertilizer to the root system. When planting fertilizer, it can be mixed with decomposed manure, or it can be applied separately. When seeding alone, it should be acidified with 10% of ash or 5% of limestone powder, and seeded immediately after seed dressing. (2) Mixed application with organic fertilizer can improve fertilizer efficiency. (3) granulated fertilizer: the phosphate fertilizer unit is made into granules, or mixed with decomposed organic fertilizer to make organic or inorganic granules, or together with nitrogen and potassium fertilizer, into a granular compound fertilizer. The particle size of the granular phosphate fertilizer is preferably 3-5 mm. (4) Top dressing: After the vegetable is in the late stage of growth, the root system can reduce the ability to absorb fertilizer, and it can be applied outside the root. Diluted 10 times with water before application and stirred well. After clarification, the supernatant is taken and diluted into a solution with a concentration of 1-3% for spraying. The spraying amount is 50-100 kg per mu, and it is preferable to spray it in the morning without dew or before or after the evening. The bottom layer of the mother liquor can be used as a base fertilizer or poured into organic fertilizer.
2, heavy superphosphate, referred to as heavy calcium, phosphorus pentoxide content of 36-54%, dark gray powder or granular, hygroscopic and corrosive, easy to agglomerate, more granulated, soluble in water It is weakly acidic and should be protected from moisture during storage. It is not suitable to be mixed with alkaline substances. The application method and technology are the same as that of superphosphate, but the dosage is halved, which is suitable for various soils and various crops. Because it does not contain sulfur, it is used in legumes, cruciferous plants and potatoes, and its fertilizer efficiency is not as good as that of superphosphate.
3, calcium magnesium phosphate fertilizer is gray-white, gray-green powder, phosphorus pentoxide content of 14-18%, also contains 40% of silica, 25-30% of calcium oxide, 10-25% of oxygen by magnesium, is A multi-formed public fertilizer based on phosphorus is alkaline, not deeper than water, does not deliquesce, does not agglomerate, is non-corrosive, and is convenient for storage and transportation. Suitable for legumes, cruciferous crops, etc., most suitable for acidic soils, especially acid soils deficient in phosphorus. In calcareous soils, the fertilizer efficiency is lower than that of acidic soils, and the fertilizer efficiency is slow, but there are rear shovel. In vegetable cultivation, calcium magnesium phosphate should not be applied alone, and should be applied in combination with calcium or heavy calcium, and fresh organic fertilizer should be applied at the same time. (1) As base fertilizer: as base fertilizer should be applied early, 215-300 kg per mu, and most of the application should be applied to 10-15 cm thick root layer. In dry land, it can be ditched or opened for application. The paddy field can be applied when it is applied in the field. (2) For seed fertilizer: When planting fertilizer, pay attention not to direct contact with seeds, 10-25 kg per mu. (3) Application after mixing with organic fertilizer: pre-stacking with pig, cow dung, manure, etc. for 1-2 months, can improve fertilizer efficiency. (4) Cooperating with the acidic and physiological acid fertilizers: Mixing calcium, magnesium and phosphorus fertilizers with potassium chloride and potassium sulfate can improve the fertilizer efficiency. However, it should not be mixed with ammonium nitrogen fertilizer.
Double J Hook,Double J Hook Straps,Double J Wire Hooks,Double Wire Display Hooks
Jiangsu Zhongyi Work Rigging Co., Ltd. , https://www.zy-rigging.com