I. Management of Maize Seedling Stage
1, corn seedling management requirements
At seedling stage, the root system of maize grew faster, but the stem and leaf grew slower. The key point of seedling management is to prevent the overground stems and leaves from growing white and promote the growth and development of roots. Make the individual distribution of corn uniform, reduce the lack of seedlings, and achieve the purpose of complete emergence and cultivation of strong seedlings.
2. Seedling management measures
(1) Check reseeding
In the process of maize emergence after sowing, due to some factors, such as low germination rate or improper application of seed fertilizer? Burning seedlings? , or because of sowing in the open field, seed bud drying, soil weeds, underground pests and diseases, etc. Therefore, after the emergence of corn, it is necessary to check the seedlings in time and replant the prepared seedlings prepared in advance.
The suitable age of transplanted seedlings is 2~3 leaves. Transplanting in the afternoon or cloudy days is beneficial to delaying seedlings and improving the survival rate of replanted seedlings. Take a soil with you when transplanting. If the soil moisture content is low, it can be hydroponic. In addition, if the shortage of corn seedlings is not very serious, we can leave two seedlings in the community and then borrow them for transplanting.
(2) Spacing and fixing of seedlings
In order to ensure the close planting density of seedlings, it is necessary to determine the reasonable planting density according to the varieties, soil fertility, water and fertilizer conditions and cultivation management level, and interplant before the seedlings are fixed.
By thinning and fixing seedlings, the crowding and shading of corn seedlings can be avoided, soil nutrients and water can be saved, and it is beneficial to cultivate strong seedlings. It is advisable to grow 3~4 leaves for the time of thinning and fixing seedlings. This is because corn is in the middle of the three-leaf stage. Weaning? At this stage, good light is needed to provide more nutrients for seedling growth. If the seedlings are too crowded, there will be competition for nutrients, which will lead to reduced production.
Because sick seedlings, insect-bitten seedlings and weak seedlings are easy to wilt after exposure at noon, the time for thinning and fixing seedlings should be carried out in sunny afternoon, which is convenient for identification and elimination. When thinning and fixing seedlings, remove diseased seedlings, weak seedlings and miscellaneous seedlings, and leave seedlings with wide leaves, deep roots, dark green leaves and solid growth. In areas with severe spring drought and serious pests, the thinning time can be appropriately later. For fields with large replanting area, topdressing should be done as soon as possible? Fat? Promote the rapid growth of replanted seedlings and make them catch up with the first-class seedlings as soon as possible.
Weeding after seedling establishment should be combined with intertillage to break soil hardening, promote root system development and achieve the goal of strong seedlings and early seedlings.
(3) Before subsoiling or shoveling.
Deep loosening or ploughing before shoveling is the main measure to promote ripening and increase production. The ground of the original ridge plot is hard, which is not conducive to the development of corn root system. Subsoiling or ploughing before shoveling can promote root development and increase root weight. But also can obviously increase the ground temperature, is beneficial to the activity of soil microorganisms, promotes the decomposition of soil organic matter and increases soil nutrients; If you encounter dry weather, you can also cut off soil capillaries, reduce water evaporation, and play a role in drought prevention and moisture conservation.
In practice, first, we should pay attention to the combination of subsoiling before emergence and subsoiling after emergence. When the ridge shape is consistent, the soil can be loosened before emergence, and the ridge-free or flat border can be planted accurately to prevent the seedlings from loosening after emergence. Second, we should pay attention to the combination of subsoiling before rain and subsoiling after rain. Flat and low-lying plots have good water content, which can be loosened before rain, and hilly and dry plots can be loosened after rain.
(4) Fertilizing at seedling stage
The application of seedling fertilizer should be determined according to plant growth and soil fertility. If the growth is vigorous, no fertilizer can be applied. If the seedlings are weak, a small amount of decomposed human and animal manure and available nitrogen fertilizer can be used, but it must not be excessive to prevent the seedlings from growing in vain.
(5), pest control
The main purpose of maize seedling stage is to control underground pests, such as cutworms, red spiders, moles, aphids, leafhoppers and so on.
Second, the management of maize ear stage
1, management requirements of maize ear stage
The heading stage of maize refers to the jointing stage to heading stage. Growth and development are characterized by vegetative growth and reproductive growth going hand in hand. This period also makes the demand for fertilizer and water in the fastest growing period of corn. Therefore, under the condition of ensuring the demand for fertilizer and water, we should coordinate the contradiction between vegetative growth and reproductive growth to ensure the stable growth in the medium term.
2. Management measures of maize ear stage
(1), tillering
Tillering is what our farmer friends often say. Tillers grow at the base of corn stalk before jointing stage. The number of tillers is related to variety characteristics and environmental conditions. When the soil is fertile, the water and fertilizer are sufficient, and the plants are sparsely planted and sown early, there are many tillers and fast growth.
Because the tillering of corn is formed later than the main stem, and the ears are not big or the ears are small, it should be pulled out in time to avoid affecting the growth and development of the main stem. Forage corn has the characteristics of tillering and fruiting, so it should be preserved to improve feed yield and seed yield.
(2), ditching soil.
Ditching and soil cultivation can turn weeds over, and in addition, it can increase the ground temperature, increase the thickness of soil layer at the root of corn, which is beneficial to the generation and extension of aerial roots, effectively prevent corn from lodging in the later stage, and is beneficial to irrigation and drainage.
(3) Top dressing and irrigation in time
The panicle stage is the key period to form large panicles and many grains, so nitrogen fertilizer should be applied again. When the corn grows to 7-9 leaves, jointing fertilizer should be applied with ditching, with 3-5 kg urea per mu and 8- 10 cm topdressing depth to prevent the fertilizer from falling into the bell mouth and burning the corn leaves. After the application of jointing fertilizer, the corn should be watered in time according to the weather change and soil moisture. The first watering should be fully and evenly watered, and the second watering should be done every 12~ 15 days.
Before heading 10~ 15 days, that is, from small trumpet to big trumpet, it is necessary to attack the panicle fertilizer, promote the differentiation of male and female panicles, and realize multi-grain, large panicle and high yield. Ear fertilizer should be determined according to seedling condition, soil fertility and application of jointing fertilizer. Generally, ammonium bicarbonate 15 ~ 20kg or urea 5 ~ 8kg is applied per mu. The base fertilizer is applied less, the soil fertility is insufficient, and the plant growth is not strong, so it is necessary to apply more early. On the contrary, it can be applied at a later and less appropriate time.
(4) spraying fertilizer on the leaves.
In the middle and late stage of maize growth, in order to prolong the growth and development of functional leaves, prevent fertilizer loss in the later stage, accelerate grain filling, increase grain weight and promote early maturity, fertilizer can be sprayed on leaves in combination with maize growth.
(1) Spraying potassium dihydrogen phosphate
Spraying potassium dihydrogen phosphate solution with concentration of 0.05~0.3 on maize leaves from jointing stage to heading stage can increase phosphorus and supplement potassium.
(2) spraying zinc fertilizer
No zinc fertilizer is applied at sowing time, but the symptoms of zinc deficiency appear during the growth of corn, and 0.2%~0.3% zinc sulfate solution or 1% amino acid zinc fertilizer can be sprayed to supplement it.
(3), corn robust element
Corn is a compound agent of plant growth regulator. After being absorbed by corn leaves, it can adjust physiological functions, make the leaves erect, thicken and darken, the internodes are short and columnar, the roots are developed, there are many aerial roots, and the development is accelerated, which can increase the yield of corn by about 20%.
Rapidly pull out the tassels after the big horn of corn, mix 30 ml of Robust with 15~20 kg of water and spray it on the upper leaves of corn plants. It should be noted that it cannot be mixed with other fertilizers and pesticides to avoid pesticide failure.
④ Spraying ethephon.
The plant height and ear position of maize treated with ethephon decreased, and the leaf color was dark green in the late growth stage. Prolonging the functional period of leaves can increase the yield. The concentration of the pesticide is 800 ml/kg, and the leaf age index is 65 during spraying, but the dosage must be controlled to avoid stiff seedlings.
(4), pest control
The main pests and diseases in this period were corn borer, followed by aphid, armyworm and meadow moth.
Third, the management of grain flowering period
This period refers to the management of the late growth period of maize from flowering to mature maize. The growth of roots, stems and leaves has basically ended. At this time, the plant is mainly in the reproductive growth stage of flowering, pollination and fruit filling.
1, management requirements for flower and grain period
All the dry matter in this period is used for reproductive growth, and the key to management is to maintain a large photosynthetic area, prevent fertilization and premature aging, keep the stems green, maintain the vigorous metabolic vitality of the roots, enhance the ability to absorb fertilizer and water, promote grain filling and strive for more grain weight.
2. Management measures at flower and grain stage
(1), staggered castration
Emasculation can reduce the nutrient consumption of male ear, meet the nutrient demand of female ear growth and development, and thus increase the yield. The emasculated maize Shixiguang crop can improve the ventilation and light transmission conditions in the later growth stage, which is beneficial to the formation of seeds and can also reduce the harm of corn borer.
It was carried out when the tassel of corn had just been pulled out by one third and the pollen had not dispersed. We should seize the opportunity of castration. Too early or too late will be bad for the growth of plants. If it is too early, it is easy to pull out the top leaves of corn. It's too late. When the pollen has dispersed, it loses its castration effect. In addition, the number of emasculated plants should not exceed half of the total, so as to avoid insufficient pollen and affect pollination.
(2) Water
The water requirement of maize from flowering to maturity accounts for more than half of the whole growth period, especially at heading and flowering stage, which is very sensitive to water, and it is appropriate to keep the soil moisture at 75%~80% of the field capacity. During this period, timely watering plays an important role in increasing the number and weight of grains and preventing premature aging. Therefore, as long as the corn plants remain green, they should be watered in time to keep the fields moist, but beware of excessive watering.
(3) Supplementary application of flower fertilizer
Applying flower fertilizer can not only maintain the vigorous function of plant leaves, but also prevent the late fertilization of corn. According to the growth situation of corn, such as late fertilization, 5~ 10 kg of available nitrogen fertilizer can be artificially applied per mu, and 0.2% potassium dihydrogen phosphate solution can also be sprayed.
(4), prevent lodging
Lodging is mostly caused by factors such as excessive plant density, insufficient light, poor root development, improper management of water and fertilizer, pests and diseases. Lodging in the middle and late stage has little effect on yield and should be avoided or reduced as much as possible. The main measures to prevent maize lodging are: adopting lodging-resistant varieties, rational close planting, optimizing water and fertilizer management, ditching and soil cultivation, and chemical control treatment.
After understanding the characteristics of each growth and development stage of maize, it is necessary to do a good job in field management, create a suitable growth environment for maize, promote its growth and development, and finally obtain high yield.