Vegetable nursery is an important part of guaranteeing high yields. It is also the basis of early maturity, high yield, and high quality of vegetables. In the process of raising seedlings, attention should be paid to the following situations:
After the seedlings are sown, the quality of the seed is poor, the bacteria is invaded, the water is too little or too little, and the temperature is low for a long time. The result is that the seed is rotten, the young shoots are dry, and the seedlings do not emerge for a long time. Preventive measures: seed germination experiments, the use of high seed germination rate, spare seeds must be disinfected before sowing, reasonable control of temperature and humidity, to ensure the seedlings full Qi Qi.
Although the seeds of the second “top shell†seedlings can germinate and sprout, the seed coat does not fall off after excavation, and the cotyledons are sandwiched to form the “top shell†seedlings, also called “hats†seedlings, which seriously affect the photosynthesis and growth of the seedlings. It is easy to form weak seedlings. This phenomenon is most common in melon crops. First, the seeds were too shallow, the topsoil was easily dried, the seed coats dried hard, and the second was that the seeds were not mature enough or old; the third was the premature release of the film. Preventive measures: Fully dip the bottom water before sowing and keep the soil moist before emergence. The depth of sowing should be appropriate. When the topsoil has just emerged, it should be sprayed with water.
The three defenses “high-legged†seedlings are also called long seedlings. The fields are characterized by fine stems, long internodes, few fibrous roots, thin leaves, light color, and poor resistance. It is not easy to survive after planting. Mainly due to lack of light, the density is too large, the night temperature is too high, too much nitrogen fertilizer, even rainy days or glass, plastic film and other dust caused by too much. Preventive measures: Control of fertilizer and water, timely ventilation and light transmission, increase the light intensity and light receiving time as much as possible, and time seedling weeding, in case of rainy days, should be opened as usual insulation cover to prevent leggy.
The four “anti-aging†seedlings are also known as stiff seedlings. The seedlings grow slowly or stop, the seedlings are small, the roots are aged and rusted, the new roots are not long, the stems are dwarfed, the internodes are shortened, and the leaves are small and thick. Such as cucumber "flower topping" phenomenon is a typical aging seedlings. After such seedlings are planted, their growth and development are slow, affecting the yield and quality. Because the bed temperature is too low or the soil is seriously deficient in water, young seedlings are inhibited from the growth and development of autumn seedlings. Preventive measures; reasonable control of temperature and humidity, nursery period should not be too long, found that aging seedlings, take timely measures.
The long-term low temperature, excessive humidity, excessive fertilization, and improper fertilization methods may cause rooting and rooting of the seedlings. Roots generally rust, roots rot, no new roots, wilting seedlings; burning roots showed yellowing roots, not long new roots, but not rot, seedlings dwarf, slow growth, easy to aging. Preventive measures: Rational fertilization, proper control of moisture, and creation of suitable temperature and humidity.
Six toxic gas pollution membranes were improperly selected. Some of the membranes were poisonous. Under the high temperature conditions, many poisonous gases were volatilized, causing the seedlings to be contaminated. Symptoms of poisoning occurred, and the leaves turned green and yellow, quickly turning white and dry. Cruciferous seedlings are the most sensitive, such as cauliflower, rape, cabbage, etc. Even if there are trace toxic gases, the cotyledons will turn white and even die. Therefore, cruciferous vegetable seedlings can be used as indicator plants for testing whether the film is toxic or not; improper application of fertilizer can also produce toxic gas, contaminate seedlings, tomato, pepper, cabbage and other seedlings are contaminated, the leaves appear round or diamond white "smoke spots" , gradually withered off; eggplant, pumpkin, carrots and other seedlings suffer damage, there will be brown "smoke spots", and gradually withered. In order to prevent the film from producing poisonous gas to contaminate the seedlings, when selecting seedlings, qualified agricultural special film must be used. If abnormal film is found to be toxic due to poisonous film, replace the film in time or increase the ventilation during the day to release toxic gas. The seedbed should be fully cooked. Organic fertilizers, especially nitrogen fertilizers, cannot be dragged in too much. Poisoning was found. During the day, ventilation was increased and harmful gases were eliminated.
There are many reasons for the cold damage caused by the seven flood-proof seedlings. The seedlings have been relatively warm during the breeding period. Suddenly, the cold flow suddenly occurs. The seedlings are often prone to freezing. After a cloudy day, rain and snow, the weather suddenly turns fine, the temperature in the shed rapidly increases, and the relative humidity rapidly increases. Falling, dehydration and death of seedling tissue, dry and dead; continuous cloudy, rain and snow days, weak sunlight, low temperature, cold resistance of seedlings weakened, prone to frost damage; nursery protection facilities closed lax, rain and snow fall from the gap to the seedlings, The seedlings are partially frozen; the water droplets that condense on the film in the morning will fall on the seedlings, and will also freeze the seedlings locally; when the seedlings are topped to the film, the shoots and leaves at the top will be susceptible to freezing injury; when ventilated, the seedbed will The temperature is high, the outside temperature is low, and the air is suddenly released. The seedlings are also susceptible to freezing, commonly known as "flashing seedlings." When the seedlings were frost-damaged, white and pale yellowish brown necrotic spots appeared on the leaves, or the edges of the leaves turned white, appearing as water-soaked, and gradually dried off. Mild cold injury, the symptoms are not obvious, but the decline in plant physiological function, prone to malformation and malformation. Preventive measures: increase the light intensity, nurturing strong seedlings, low-temperature hardening seedlings, control of humidity, rational preparation of bed soil, protection facilities should be tight, cold before cold, do cold insulation work.
Eight pest prevention pests seed disinfection and soil treatment before sowing, beware of damping-off disease, blight, early blight, gray mold and other seedling disease, while preventing the invasion of underground pests, aphids, planthoppers, spider mites. In terms of prevention and control measures, we must pay attention to agricultural control and biological control, limit the use of chemical control, and strictly prohibit the use of highly toxic and high-residue pesticides.
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