1, soil moisture is too high or too low can easily lead to lack of seedlings. When soil moisture is sown at the time of sowing or excessive moisture is caused by rain after sowing, the seed is injured by suction, the seed becomes moldy and rot, and ridges are formed. The soil moisture is too low to meet the water requirement for seed germination. Rotten species, resulting in poor field emergence.
2, the soil temperature is low. Due to continuous low-temperature weather after sowing or sowing, low seed activity, slow germination, long soil retention time, which can easily cause seed rotten seedlings and lack of seedlings and ridges, and corn seeding at a low temperature of 10-15 degrees in case of rain, causing soil water Larger parts make the seeds absorb cold and absorb cold water at a low temperature for a short time, resulting in failure of normal seed germination. After normal seeds are chilled, they cannot germinate even if they are given suitable conditions.
3, lack of oxygen in the soil. Deep sowing, excessive soil moisture or compaction, poor soil permeability, lack of oxygen, affecting seed metabolism, seed germination caused by lack of seedlings.
4. The poor quality of soil preparation, the large amount of field clods, the residual film, residual culms, and weeds affect seed emergence.
5. Plant diseases and insect pests cause dead seedlings, and underground pests such as tigers, earthworms, cockroaches, and wireworms harm corn seedlings, causing dead seedlings to become seedlings, resulting in insufficient seedlings in the field. The main disease of corn seedlings is corn seedling blight, and the symptoms are as follows: More corn began to develop in the 2-3 leaf stage. The diseased seedlings had yellow leaves with scorching edges. The leaves gradually dried up from the bottom, and the seedlings were observed. Roots were stunted, root hairs were reduced, and the roots became brown.
6, rational use of fertilizers and pesticides to prevent the occurrence of fertilizer burning seedlings or phytotoxicity.
7. After the seeds are coated, they should be air-dried and should be sown. At the same time, attention should be paid to the fact that seeds with a low seed germination rate of 95% should not be sown on-demand. Otherwise, once the germination conditions are not suitable, it will inevitably cause varying degrees of seedling deficiency.