The primary cause of the lack of nutrients in celery is poor soil fertility, low nutrient availability, and insufficient fertilization. In addition, there are many reasons for the lack of nutrients.
1, lack of nitrogen. With more rainfall, nitrogen leaches more; the cation exchange capacity of sand and sandy loam is small. Symptoms of nitrogen deficiency: The lower leaves turn white or yellow and grow poorly. Treatment methods: Apply nitrogen fertilizer; Apply nitric nitrogen fertilizer when temperature is low; Apply good quality manure fertilizer; Foliar spraying 0.5%-1% urea solution, spray time should be selected in sunny days, if necessary, you can spray two or three Times, 7-10 days apart.
2, lack of phosphorus. Volcanic ash soils are prone to phosphorus deficiency; soil pH is low and the soil is compact; low temperature can seriously affect the absorption of phosphorus. Symptoms of phosphorus deficiency; yellowing of lower leaves, leaf color of young leaves did not change significantly. Orthodontics: Apply superphosphate as base fertilizer; spray 1%-3% of superphosphate solution on the foliar; spraying time is best when there is no dew or morning in the morning so that the solution remains on the leaf surface for a period of time. To absorb.
3, potassium deficiency. The sand is prone to lack of potassium, and fruit development is short of potassium. The use of lime fertilizer affects the plant's absorption of potassium, and the absorption of potassium by plants under low-temperature olivine illumination weakens. The absorption of potassium by potassium also inhibits potassium absorption. Symptoms of potassium deficiency: yellowing of the lower leaves, brown spots appearing between the veins, and gradually spreading to the upper leaves, causing poor growth. Orthodontic treatment: Potassium fertilizer was added, and organic fertilizer was applied more. Foliar was sprayed with 1% potassium sulfate solution or 1% ash leaching solution.
4, calcium deficiency. The soil itself lacks calcium; soil salt content is high, inhibiting root absorption of water and nutrients; soil drought, making the soil solution concentration increased, reducing the root water absorption, thereby inhibiting the absorption of calcium; nitrogen fertilizer application, especially ammonium nitrogen application will Inhibit calcium absorption. Symptoms of calcium deficiency: Growth is hindered, young leaves in the center die, and the white veins and brown spots appear at the apical veins of the new leaves in the vicinity of the growth point. The spots gradually expand and connect, and the leaf margins die. Orthodontics: Apply lime; timely irrigation, to prevent soil drought; foliar spray 0.3% -0.5% calcium chloride solution, usually spray every 7 days or so, even spray 2-3 times can be effective.
5, magnesium deficiency. The excessive application of potassium will affect the absorption of magnesium; when the requirement for magnesium is large, the root absorption will not be able to keep up, and the symptoms of magnesium deficiency will be: the leaf color will be light green. Orthodontics: supplement magnesium fertilizer, generally foliar spray 1% magnesium sulfate solution 2-3 times, spray once every 7 days or so.
6, iron deficiency. Alkaline soils, calcareous soils, and phosphorus with high pH affect iron absorption too much; the soil is too dry and too wet; the activity of roots is also affected by iron deficiency at low temperatures; too much copper and manganese easily react with iron. Symptoms of iron deficiency: The leaves of young leaves turn yellowish-white or white. Correction method: When the soil pH reaches 6.5-6.7, it is prohibited to use alkaline fertilizer such as lime. When there is too much phosphorus, deep plowing methods are used to reduce the phosphorus content; 0.21%-0.3% ferrous sulfate solution is sprayed on the leaves.
7, lack of boron. Soil acidified boron was leached; excess lime was used; soil was dry, organic fertilizer was less applied; potassium fertilizer was used excessively. Symptoms of boron deficiency: There are many cracks in the stems and leaves, the growth and development of the heart leaves are blocked, and the central leaves are deformed and the growth is poor. Orthodontic treatment method: apply shed acid or shed sand as base fertilizer; fertilize with 0.1%-0.25% borax solution.
8, zinc deficiency. Soils with pH greater than 6 are prone to zinc deficiency, especially calcareous soils; the chelation of zinc by organic matter will also reduce the effectiveness of zinc; in soils with low soil temperatures, the use of large amounts of phosphate fertilizers or soils with high available phosphorus may be lacking. Zinc. Symptoms of zinc deficiency: Leaves tend to roll laterally, pigments may be found on stems. Orthodontic treatment method: apply physiological acidic fertilizer (such as ammonium sulfate, potassium sulfate, etc.); apply zinc fertilizer and mix it with physiological acidic fertilizer and apply it uniformly; apply foliar spray of 0.05%-0.2% zinc sulfate solution.
9, lack of copper. When the organic matter content of peat soil and swamp soil is high, copper is fixed into a stable complex by organic matter, or is closely adsorbed by organic matter, and the effectiveness is reduced. Symptoms of copper deficiency: Light green leaves, yellow brown spots on the lower leaves. Orthodontic treatment method: apply copper fertilizer once in 3-5 years; apply physiological acidic fertilizer to prevent copper from forming hydroxide precipitate; spray foliar 0.05%-0.1% copper sulfate solution.
10, lack of manganese. A large amount of lime is used to increase the pH value of the soil and "induced Mn deficiency" occurs; manganese sulfate is easily precipitated when a large amount of phosphate fertilizer is applied. Symptoms of Mn deficiency: Light green or even yellow between leaves of the margin. Orthodontic treatment: Do not apply lime when the pH is higher than 6.5; pay attention to control the use of excessive phosphorus fertilizer; use a concentration of 0.05% -0.1% manganese sulfate solution foliar fertilizer.
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