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First, sowing too deep sowing is not easy to emerge, too deep will appear weak seedlings, yellow seedlings, sowing depth should be controlled at 3-5 cm; sowing at the same time, apply a certain amount of seed fertilizer, can promote seedling growth, such as sowing When applying 3 kg of ammonium diammonium per acre, it can effectively control the yellowing of corn seedlings.
Second, the seedlings, Dingmiao timely maize emergence, should be 3-4 leaves in the corn when the seedlings, 6-7 leaf when the Dingmiao, to avoid seedlings crowded, competing with each other, compete for water, glory, the formation of weak seedlings, diseased seedlings Yellow seedlings; the number of seedlings per mu should be flexibly controlled according to the variety, and the seedlings should be seeded at the density required by the cultivated variety. Such as Zhengdan 958, should be dense planting, about 4,000 acres of plants; Xianyu 335 suitable for sparse planting, about 3200 acres left.
3. Insufficient watering Before watering, the water is not enough before the seeding or sowing of the corn. The seeds do not get sufficient water, which affects the normal germination and emergence, and the unearthed time is too long to cause weak seedlings and yellowing at the seedling stage.
Fourth, waterlogging seedlings Waterlogging seedlings corn seedlings often coincide with the rainy season, low-lying plots of poor drainage or wheat harvest at the time of water pressure, resulting in yellow seedlings.
5. Diseases If the seedlings encounter long-term low temperature and rainy weather, it will cause the emergence and epidemic of corn seedling blight. Seedling blight occurs at the beginning of the second and third leaf stages. The leaves of the diseased seedlings are dry and yellow, and the edges are scorching. The leaves gradually dry up from the bottom up; the root hairs are less, and the roots are brown and stunted, resulting in weak seedlings of the yellow seedlings. Note that at the beginning of the disease, the corn base was sprayed with hymexazol plus foliar fertilizer.
6. Insect pests Maize seedling pests include cotton bollworm, golden needleworm, aphid, armyworm, thrips, Swedish rod fly, ground tiger, and ploughing, etc. The cultivating sunflower nymph is mainly concentrated in corn seedlings with nymphs and female adults. Ground stems, roots, and leaf sheaths absorb sap, causing the damaged corn sheath to yellow and dry. Timely use 40% phoxim 500-1000 times solution or other systemic insecticide 500-1000 times to spray on the stem base of corn seedlings or to irrigate the roots; It only harms the gramineous plants.) Other insect pests can be made using generally effective and low-toxic insecticides.
Seventh, herbicide harm herbicides improper use A small number of farmers at random increase the dosage of herbicides; blindly mixed with other pesticides; drug concentration is too high; sprayer interoperability; fake and inferior herbicides on the impact of post-action, will cause corn yellow seedlings.
Eight, the deficiency of corn is a sensitive zinc crop, zinc deficiency will appear white seedlings, corn seedlings appear yellow. The general zinc fertilizer is based on basic application; if zinc deficiency is found during the growth period, it can be used in the seedling period with 1-2kg of zinc sulfate mixed fine soil 10-15kg, application or hole application; or with 0.1% zinc sulfate solution (Note: The concentration should not exceed 0.4% to avoid causing fertilizer damage. Spraying twice at intervals of 7 days between the seedling stage and the jointing stage, 60 kg of fertilizer solution.
Eight Reasons for the Yellowing of Corn Seedlings
Summer maize is one of the major grain crops in our province. In recent years, the planting area of ​​summer maize in Hebei province has been approximately 32.8 million mu. With the increase in grain prices, people have begun to pay attention to the cultivation of summer maize, and nowadays have come to summer corn. During the sowing season, in order to avoid the occurrence of yellowing of corn seedlings with different degrees in different areas, the reasons for summing up are as follows: