First, the cause of the hollow 1, in the protective cultivation, if the temperature is too low, lack of light or frost damage, resulting in decreased photosynthesis of the leaves, and the root system of nutrients, moisture absorption and operation blocked and hollow. 2, in the open field cultivation, high temperature and drought is the main cause of hollow, especially in summer day and night temperature difference is too small, more respiratory consumption, if the uneven supply of soil moisture, physiological growth during the growth of celery will inhibit the roots of various Absorption and transport of the elements not only affect the growth of the terminal buds, but also thicken the thick-walled tissues in the petiole, age the cells in the transposition and delivery tissues, and rupture the cells in the parenchyma cells. If the harvest is too late, the root absorption capacity is reduced, malnutrition, cell rupture, loose tissue, petiole aging and hollow. 3, improper management of water and fertilizer will cause hollow. The celery roots have weak absorption capacity and strong fertilizer-resistance, and require more comprehensive fertilizers. Nitrogen fertilizers always occupy a major position during the growth period. Soil nitrogen concentration is about 200X10-6, phosphorus content is about 150Xl0-6, and potassium content is 120X10-6. Right and left are appropriate. Insufficient phosphate fertilizer is unfavorable to the differentiation and elongation of leaves and thin seedlings in the early stage of growth. Therefore, it is important to apply phosphate fertilizer at the early stage. In the middle and later stages, potash fertilizer plays a significant role in transporting nutrients, stout stems, fullness, and luster. When the fertility needed for the prosperous period is insufficient or lack of water, the growth is inhibited and the petiole will be hollow. If the soil is dry or excessive nitrogen fertilizer will interfere with the absorption of trace elements boron and calcium, celery is sensitive to boron, when the plant is lacking, the petioles will be longitudinally cracked, the heart leaves brown cracking, calcium deficiency can easily induce heart rot. The celery spray 920 can increase production, but the water and fertilizer should keep up after spraying, and spraying too much can be done, otherwise there will be hollow phenomenon. 4. Under the same conditions of fertilizer and water, the soil is salty and alkaline, and the soil is more likely to be hollow when the soil is more viscous or sandy and the pests and diseases are serious. Second, prevent hollow measures 1. Use pure, high-quality, solid, fine varieties to buy seeds from trusted seed agencies. 2, choose suitable land planting. The sandy loam rich in organic matter, water retention and fertility, and good drainage and irrigation conditions is suitable. The pH of the soil is preferably neutral or slightly acidic, and clay and sandy soils should not be planted. 3, adjust the appropriate temperature. Celery is cold-resistant vegetables, requires cold and humid environmental conditions, celery cultivation indoors, the daytime temperature of 15-23 °C is appropriate, the maximum not more than 25 °C, about 10 °C at night, not lower than 5 °C, overcast, rain, snow , The wind temperature is lower, but not too low, to prevent freezing injury and early twitching. According to the humidity appropriate ventilation to reduce air humidity, reduce disease, can be used assimilation, reduce respiratory consumption, so that the petiole is full of hypertrophy. 4, timely and appropriate water and fertilizer management. The base fertilizer should be applied adequately and spread evenly. About 5,000 kg of organic fertilizer should be applied at a rate of 667 square meters. It is best to apply 100-200 kg of fermented chicken manure or about 15 kg of diammonium phosphate. Miao Fei, about 10 kilograms of ammonium sulfate per 667 square meters of water or fermented human waste. During the growing season, the topdressing fertilizer is mainly composed of quick-acting nitrogen fertilizer and potash fertilizer. Each time about 20 kg per 667 square meters, the fertilizer is topdressed every 15 days or so. After spraying 920, the fertilizer should be top-dressed and watered, and the fertilizer should not be removed. For ground-breaking measures, if a boron deficiency is found, a 0.3%-0.5% solution may be used for foliar application. In the vigorous growing season, we should always keep the bauxite moist, do not water, the soil temperature is maintained at 60% -80%, in the summer to pay attention to drainage and flood control. 5, timely prevention and control of pests and diseases, to maintain a strong photosynthesis ability of leaves, adequate supply of nutrients needed for parenchyma cells in the petiole, so that plants grow strong. In addition, harvesting is also an important measure to prevent the hollow phenomenon. Shanghai J.Shine Co.,Ltd , https://www.jshinechem.com