Recently, many vegetable farmers have reported that the tomato seedlings and cucumber seedlings that have just been planted for a long time have frequently appeared wilting and dead trees. However, when these seedlings were brought in from the seedling factory, their leaves were dark green and strong and robust. What were the reasons? What happened to dead seedlings?
Cause Analysis
The water temperature is too high. The root temperature is high in summer. Vegetable plants grow rapidly and require large amounts of water. Vegetable farmers are generally more water-fed, but excessive watering is very unfavorable to the growth of seedlings. On the one hand, excessive watering will cause the root layer of seedlings to be relatively shallow, the roots circle around the surface without deep-seating, the weak stress resistance is vulnerable to the invasion of diseases and pests, and the emergence of weak seedlings; on the other hand, serious over-watering will lead to soil. The reduction of oxygen in the medium causes dead trees, especially in greenhouses with poor soil water permeability.
High-temperature burns The newly planted seedlings are generally tender before the seedlings are slowed, with high summer temperatures and strong sunlight. The transpiration of seedling leaves is enhanced under high temperature and strong light conditions, and wilting is easy to occur, which leads to dead trees. At the same time, the high temperature environment is not conducive to the growth of roots, and the water absorption capacity of the roots is poor, resulting in insufficient water supply. In addition, high temperature and strong light conditions such as air drying blades are prone to burns.
Rhizome Disease Rhizome disease is the main cause of dead vegetables, especially in greenhouses with longer planting periods. The soil environment is getting worse and worse. Even if the soil is sterilized before planting, it is sometimes difficult to avoid roots. The occurrence of disease. In addition, the high-temperature and high-humidity greenhouse environment in the summer is very conducive to various diseases, such as damping-off, blight, and rot on the stem base, which cause rot in the stem base of the plant. root".
1, damping-off disease: damping-off disease occurs in the roots or soil on the base of the seedling stems, was immersed in browning, the disease Department collapsed and lost support ability, seedlings fell to the ground, and quickly wilted.
2. Stem rot: Mostly occur after seedling colonization. Dark brown irregular lesions occur at the base of the stem, spreading to the left and right, resulting in necrosis of the base of the stem, shrinking and thinning, the aboveground leaves wilting and turning yellow, the whole plant withered. The reason for this is that the soil is moist, and the continuous cropping causes the accumulation of germs. The base, through agricultural operations, produces wounds that invade germs.
3, blight: mainly harm the seedling stem base or underground root, initially oval or irregular dark brown lesions, the disease department gradually sag, shrank, when the lesion expands around the stem after a week of dry death, but not lodging. Mild diseased plants only saw brown pitted spots but not withered. When the humidity of the seedbed was high, faint spider silky mildew was seen in the diseased part.
Unfermented Manure and Chemical Fertilizers Burned Roots Before seedlings are planted, incomplete application of manure is applied to the base fertilizer, or excessive chemical fertilizers are applied to cause burning of roots.
Responses
First, the rational use of fertilizer to reduce the amount of base fertilizer used to prevent overheating in order to prevent burnt roots caused by incomplete decomposition of manure, the best choice of commodity organic fertilizer or bio-organic fertilizer; at the same time, chemical fertilizers use less or use controlled-release chemical fertilizers to reduce fertilizer Damage to the root system.
Secondly, the pharmaceutical market is very important nowadays, the tray has become an indispensable measure for vegetable planting. The role of smashing plate is mainly manifested in three aspects: First, it can control or reduce the harm of crop root disease; Second, it can control or reduce the harm of soil pests to seedlings; Third, it can promote root development and shorten saplings time.
Commonly used root recipes are: Hymexazol 1000x, Prec 500x, 2% Avastin 1500x, Smart Compound Chitin 400x, or 963 Rhizogenin 300x, soaked with good solution Miao dish.
Again, pre-ground watering, late water control, cultivating strong seedlings, planting water before the seedlings are planted, timely watering, planting water to be drenched, depending on the weather conditions and soil conditions, see dry water, to avoid high soil temperature caused by seedling burns. When easing the seedlings, water should be poured in the morning. At the same time, the amount of water should not be too large. Generally, water can flow to the front of the planting line. In order to prevent root diseases, it can be flushed together with microbial agents, such as the Rembrandt. After planting about 10 days after the seedlings are transplanted, appropriate control of the water should be conducted in a timely manner, and the roots should be tied down, and the rooting agent should be used for rooting.
Finally, about 7 days after timely rooting, disease prevention, and planting, you can use Hymexazol, Precore with rooting agents or chitin to spray the stem base, and do not water it for 1 day before and after irrigating the roots.
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