What are the key technical measures for increasing yield in the late growth stage of corn?
To achieve high corn yields, the following four key techniques should be carried out in the late growth stage.
1. Pull out barren stalks. After the booting stage of corn, time should be taken promptly to pull out the barren plants that have weak growth, slender stalks, and either no ears or ears that cannot grow large and do not silk, pollinate, or set seed, and use them as green fodder. This can improve field ventilation and light penetration, reduce fertilizer consumption, favor normal plant growth and development, and promote the formation of large ears and large kernels.
2. Prevent drought and drain waterlogging. The tasseling and flowering stage of corn is the period of greatest water demand in its life cycle, and also the critical period for corn water needs. If there is little rainfall, dry air, and soil drought during this period, root activity is impeded, and corn pollen and silks easily lose water, leading to reduced vitality, affecting pollination and fertilization, and causing yield decline. At this time, irrigation should be carried out promptly to enhance corn plant vitality, increase photosynthesis in corn leaves, promote the transfer of nutrients to the ear, and support overall ear development, preventing kernel abortion at the tip of the ear. Therefore, irrigating during the flowering stage to prevent drought and applying timely topdressing are important technical measures for achieving high-quality and high-yield corn. At the same time, if there is excessive rainfall, high soil and air humidity, or even waterlogging in the field, root activity is impeded, which is unfavorable for flowering and pollination and affects pollination and fertilization. Therefore, after heavy rain, fields should be inspected promptly and ditches cleared to drain standing water and prevent waterlogging damage.
3. Artificial detasseling. Corn detasseling means manually removing the tassels of some plants in a certain proportion when the tassels have just emerged but have not yet shed pollen. Before detasseling, it is best to first remove the tassels of plants that tassel early, weak plants, and diseased or insect-damaged plants. The proportion for detasseling can use alternate-row detasseling, or remove one row out of two, or remove alternate plants within the same row. The principles of detasseling are: remove weak ones and keep strong ones, remove those in the middle of the field and keep those at the edges, remove those on the leeward side and keep those on the windward side; remove more in good weather and less in bad weather. Generally, the number of detasseled plants should be controlled at 35%-40% of the total number of plants in the whole field.
4. Supplemental pollination. Corn is a monoecious crop with separate male and female flowers on the same plant, and its natural cross-pollination rate is very high. Artificial supplemental pollination can compensate for pollination of late-emerging silks at the top of the ear, overcome the effects of unfavorable factors such as drought or excessive rainfall, reduce bare tips and missing kernels, achieve large and plump kernels, and increase yield.
The specific method is: when corn is flowering and silking, choose a windless sunny morning, wait until the dew has dried, and when the male flowers are shedding pollen heavily, use a long rope pulled by two people perpendicular to the row direction for pollination, or use a T-shaped frame to push the corn plants to promote pollen shedding. Carry this out once every 1-2 days, continuously for 3-4 times, and the pollination requirements can be met.