What is the reason for maize lodging? How to prevent it?
1. What is the reason for maize lodging?
1, change reason
Different maize varieties have some differences in plant height, ear height, root development, stem diameter and mechanical strength, so different varieties have different lodging resistance. Generally, varieties with tall plants, low ear position, strong roots, thick stems and good toughness have strong lodging resistance.
2. Planting density
When planting corn, if the planting density is too high, it will lead to poor ventilation and light transmission of corn plants, resulting in slender and fragile stem growth, increased plant height, higher ear position, higher plant center of gravity and worse lodging resistance. Once there is strong wind, rain and other bad weather, it will cause lodging or lodging.
3, the harm of pests
The harm of stem pests such as corn borer is also an important reason for maize lodging. They will drill into the straw and eat the corn straw. Once encountering windy weather, it will lead to stem collapse.
4. Improper site management
If the field management is not timely, such as waterlogging at seedling stage, excessive fertilizer and water at jointing stage, excessive nitrogen application, excessive growth of maize stems and leaves, excessive jointing stage, poor development of mechanical tissue at internodes, excessive stretching of internodes under ears and corresponding rise of ear position, this kind of maize is easy to lodging.
Second, prevent corn from lodging.
1. Select varieties with strong lodging resistance.
To prevent maize lodging, we should start with seed selection and sowing. In production, according to the local climatic conditions, we should choose maize varieties which are suitable for local planting, have strong lodging resistance and high yield. When buying corn seeds, we should carefully read the introduction of corn varieties, especially pay attention to their lodging resistance and suitable planting areas, and we should not blindly introduce and select seeds.
2, timely sowing
When sowing, adjust the sowing date of corn according to the local climate change law for one year. Staggered the harm of wind and rain season before and after the heading date of corn to reduce the impact of bad weather on corn.
When sowing, seed fertilizer should be applied with the seeds, and the amount of fertilizer should not be too large. It is suggested to apply NPK compound fertilizer 15~20㎏ per mu. If the application amount of seed fertilizer is too large and there is too much rain at seedling stage, the aboveground parts of seedlings will grow vigorously, leading to lodging of maize seedlings in the later stage. When applying seed fertilizer, seeds must be separated from seed fertilizer to avoid burning seeds or seedlings.
3. Do a good job in site management
In the process of maize growth, seedling stage to heading stage is the key period for maize lodging prevention.
Seedling stage refers to the period from sowing to jointing stage, which is characterized by long roots, increased leaves and differentiation of stem nodes. The heading stage of maize refers to the period from jointing stage to heading stage, when maize is in the stage of differentiation and formation of fruiting organs. The first half is from jointing stage to big bell stage, mainly the growth of stems and leaves; In the second half, from the big bell mouth to the tasseling, the female ear differentiation is the main one.
(1) Keep seedlings scientifically at seedling stage.
Different varieties of corn have different seedling densities. When reserving seedlings in the field, it is necessary to scientifically reserve seedlings according to the characteristics of varieties and create external environmental conditions suitable for corn growth. The high density of remaining seedlings leads to insufficient light in the field, closed plants, thin stems, long internodes, tender and weak mechanical tissues of stems, which are prone to lodging once they are attacked by wind and rain. Therefore, seedlings should be thinned in time at the three-leaf stage and fixed in time at the five-leaf stage to prevent high seedlings or weak seedlings.
It is also necessary to squat seedlings properly at seedling stage. Crouching seedlings can inhibit the vigorous growth of basal stem nodes of corn, promote the downward growth and deep rooting of roots, and thus reduce the probability of lodging. When squatting seedlings, under the premise of ensuring no drought and proper application of seed fertilizer, fertilization and watering are generally not needed at seedling stage. In order to prevent the overground part of seedlings from growing too fast and lodging when encountering wind and rain in the later period.
At the seedling stage, intertillage should be carried out to loosen the soil and promote the root system to be firmly tied. The depth of intertillage should be shallow, and it is suggested that the depth of intertillage should be 3~5 cm, and the squatting of seedlings should end at the beginning of jointing. This measure is mainly suitable for spring corn, because summer corn enters the high temperature and rainy season soon after emergence, and there is basically no chance to squat.
② Prevention of heading date
The ear stage is the most vigorous growth stage in the growth cycle of maize, and this period is also the high incidence period of maize lodging, so necessary field management measures should be taken.
Fertilization: At jointing stage, the stem nodes at the base of maize plants began to elongate rapidly. At this time, if a large amount of nitrogen fertilizer is applied, the elongation of basal stem nodes will be accelerated and the risk of lodging will increase. Therefore, in actual planting, it is generally not recommended to apply nitrogen fertilizer at jointing stage of corn. If the seed fertilizer is applied sufficiently, the topdressing stage of nitrogen fertilizer can be postponed to the big bell mouth stage. When fertilizing at the big bell mouth stage, it is best to use nitrogen fertilizer in combination with potassium fertilizer which can strengthen the stems, so as to balance the nutrition of corn, avoid the white growth of plants due to only applying nitrogen fertilizer, and thus improve the lodging resistance of plants. When fertilizing, urea 15 ~ 20kg and potassium sulfate or potassium chloride 10 ~ 20kg are applied per mu for fertilization. Watering: After fertilization, in order to prevent the volatilization loss of nitrogen fertilizer in high temperature climate, water it in time to improve the utilization rate of fertilizer. At the big bell mouth stage, the elongation of the internodes at the base of the stem has stopped, which is the time when aerial roots grow in large quantities, so watering at this time can promote the growth of aerial roots, which can flourish and effectively prevent maize from lodging. 4, chemical control to prevent lodging
In order to reduce the harm of corn borer and other pests to corn, 3% phoxim granules were used to fill the heart at the big bell mouth stage, with 250 grams of phoxim granules and 5~6 kilograms of fine sand per mu. After being stirred evenly, it is sprinkled into the heart leaves of corn, which has a good lodging prevention effect.
Spraying some chemical regulators with growth inhibition can also effectively control the height of maize plants, thus achieving the purpose of preventing maize from lodging. When maize leaves are 7~ 1 1, that is, at the big bell mouth stage, spraying 30 ml of methylpiperidine and 40 kg of water per mu can shorten the internode length of base 1~3, reduce the plant height of maize 10~/5 cm and the ear position/kloc-.
If chemical control is not carried out at the big bell mouth stage, 50% chlormequat chloride can also be sprayed at the early heading stage, with 30 grams of chlormequat chloride and 20~30 kilograms of water per mu, and the pesticide can be evenly sprayed on the upper leaves of corn to ensure that it is not sprayed again and not missed. If it rains within 6 hours after spraying, it should be sprayed again, but the dosage is halved, which can effectively prevent lodging.
5. Plant cultivation
Before jointing to ridge sealing, the corn should be ridged once, and the height of ridging should be buried in the first internode at the bottom of the stem. Cultivating soil can promote the development of aerial roots at the base of maize and enhance the lodging resistance of plants, which is one of the effective measures to prevent maize lodging.
Knowing the reason of maize lodging and the key period to prevent lodging, combined with scientific and reasonable field management, can reduce the probability of lodging and lay a solid foundation for high yield and harvest of maize.