Technical points of planting corn

How to grow corn has always been a problem for many growers. What should we pay attention to when planting corn? Let's take a look at the key points of corn planting technology that I carefully recommend for everyone, hoping to help you.

Key points of maize planting technology

1, select disease-resistant parents (seed production) or varieties.

It is suggested that scientific research units and seed production enterprises should choose parents and combinations with excellent resistance to ear rot, establish disease-free seed production bases and cultivate healthy seeds. At the same time, county seed companies and agricultural technology centers should focus on the resistance to the disease in the introduction test of new corn varieties, and varieties with poor resistance should not be introduced; Zhuanglang county should actively introduce new varieties with high yield and disease resistance on the basis of popularizing disease-resistant varieties.

2. Plastic film mulching is suitable for early sowing.

Full or semi-mulching with plastic film and early sowing in time can make corn mature early, reduce the water content of ear axis and grain of susceptible varieties, and effectively reduce bacterial infection during harvest and storage.

3. Peel off the bracts in time to prevent rain and moisture.

The harvest time of corn is generally autumn rain, and the harvested ears should not be piled too thick. Bracts should be peeled off as soon as possible and hung in a ventilated and sunny place to dry. Ears that can't be strung together should be thinned and dried, and turned frequently to prevent heat from getting sick. If it rains, cover it in time to prevent it from raining. Break the rotten top of the diseased ear to prevent the ear rot from spreading again.

In the process of stripping bracts, the moldy top of diseased ears should be removed at the junction of diseased and healthy areas to prevent further spread of diseases and increase losses. According to the experimental observation, the rotting length of the top of the ear was extended from 3cm to 7cm after 3 days of rain without peeling the bracts. In the early stage of threshing, ear rot will expand from 5cm to 15cm if the bud leaves are stripped and the moldy part at the top of the diseased ear is not removed. The rotten part of the ear is not completely removed, and the ear rot will expand by 2-5 cm in the early stage of threshing; And if it is thoroughly cleaned, there will be no ear rot.

4, early threshing, mildew.

Pick out the diseased ear after harvest, thresh it as soon as possible, and dry it in the sun or in the pit to prevent the seeds from being further infected by germs. Treating corn stalks to reduce the source of primary infection. The accumulation of corn stalks, cob and stubble is a favorable place for Fusarium and corn borer to overwinter. Therefore, corn stalks, cob and stubble must be thoroughly treated in time by feeding (livestock), ammonifying (ammonifying forage), crushing (feeding pigs), retting (as fertilizer or biogas filler) and burning (cooking in into the pit), so as to reduce the primary infection source of pests and diseases.

5. Seed selection and coating

Because the survival time of maize seed surface pathogen is longer than 1a [5], the production and business operation units should carefully select seeds, eliminate minor disease seeds and use 20% Fu? G seed coating agent coating [14], the dosage per 100kg seed is 444.4-800g, or more than 30%? g？ The dosage of Fu seed coating agent is 2 14-300 g per 100kg seed.

6, chemical control

At the corn trumpet stage, 5 kg of river sand with a diameter of about 2mm was washed, stirred evenly with 20% fenvalerate 8- 10ml and 50% carbendazim WP50g to make granules, and poured 60-75 kg/hm ~ 2 into the gap between the center of corn heart leaves and 4-5 leaves that make up the heart leaf cluster to avoid dew condensation and application when rolling leaves. According to the experiment, the prevention and treatment effect of heart irrigation not only reached 6544. At the same time, the fruit was treated with 50% carbendazim WP 1000 times solution before corn harvest15 days.

Cultivation techniques of maize

sow seeds

The natural conditions of corn producing areas in China vary greatly. According to the local frost period, soil texture, soil fertility and planting month, the yield of forage corn and purslane hybrid is high. We should also pay attention to the breeding of improved varieties and rationally arrange the area of dantian.

Temperature: The sowing date of maize is affected by temperature and humidity, and the optimum temperature for seed germination is 25 ~ 30℃. The daily average jointing period is above 65438 08℃. The average daily temperature from heading to flowering is 26 ~ 27℃. The best sowing date of spring sowing corn is 7.6cm, and the upper layer is 65438 05℃.

Reasonable spacing: 3-4 kg per mu, 4,000-6,000 plants per mu. Planting method of forage corn. Unicast, convenient mechanized operation from planting to harvesting. Intercropping with soybean, soybean, pea and vetch can increase the yield of protein per unit area.

Seeds: The corn seeds we grow are all hybrid seeds. In layman's terms, we plant it once a year. We mainly use its heterosis to improve the yield and quality, disease resistance and stress resistance of corn. We don't choose to plant every other year, mainly because of low germination.

Nutrition: The main function of base fertilizer is to improve soil fertility, improve soil physical properties, loosen soil, facilitate microbial activities, replenish nutrients in time at seedling stage, promote root development, and create good environmental conditions for cultivating strong seedlings.

operate

Maize plants are tall, with high yield of seeds and stems and leaves, which need careful management. Fertilization, irrigation, chemical weeding and pest control are the key technical measures for high-yield cultivation and management of maize. To obtain high yield and high quality corn, apply 2000 per mu before sowing? 3000 kilograms of high-quality manure as base fertilizer. Apply 4 when sowing? 5kg/ mu sulfuric acid, 15? 20 kg/mu of calcium superphosphate and 2-3 kg/mu of chlorinated trees are used as seed fertilizer, and nitrogen fertilizer is applied at jointing, booting, heading, flowering and filling stages. The nitrogen application rate in the whole growth period is 10-20kg/ mu. N: p: k is 1: 0.5-0.8: 0.8. Corn likes semi-arid climate, but it is very sensitive to water. During the flowering period, a corn consumes about 2 kilograms of water every day, 3? 4m3, and the water consumption in the whole growth period is 250? 350 cubic meters. Different corn needs different moisture. The period from 10 day before heading to 10 day after heading is the most water-demanding and water-sensitive period in the whole life of maize, which is called "? Critical period of water demand? . Irrigation should be carried out during this period. Corn is usually watered for a lifetime. 4 times, depending on different regions and specific conditions. At present, most irrigation methods in China are furrow irrigation and border irrigation. Recently, sprinkler irrigation and drip irrigation have been developed, which not only saves water, but also irrigates evenly. Corn is not tolerant to waterlogging. In areas with high groundwater level and heavy rainfall in the south, attention should be paid to drainage or ridge farming and field combination to prevent waterlogging.

Eliminate pests and diseases

Corn diseases and insect pests include leaf spot, head smut, smut, black-streaked dwarf, bacterial wilt, leaf spot, leaf spot, moth, virus, stem rot, rust, anthracnose, mildew, dwarf mosaic, common mosaic and other diseases and armyworm, corn borer and bedbug. Measures such as selecting disease-resistant varieties, strengthening cultivation management, rational rotation and chemical control should be taken to prevent and control bacterial wilt in time, and prevention and control should be carried out by selecting disease-resistant varieties and strengthening management.

I. Great Leaf Blight of Maize

Symptoms: Great Leaf Blight mainly damages maize leaves, and even leaf sheaths and bracts in severe cases. It starts from the lower leaves of plants and then spreads upward. The lesion was spindle-shaped, taupe or yellowish brown, with a length of 5- 10 cm and a width of 1 cm. Some lesions are larger, and the leaves are burnt in severe cases. When the weather is wet, a gray-black mold layer can densely grow on the diseased spot. In addition, there is also a kind of lesion, which occurs in resistant varieties and spreads along the veins, which is brown necrotic stripes and generally spreads slowly. Summer corn is generally more serious than spring corn.

Pathogenicity: Pathogenic bacteria overwinter on the residual diseased plants in the field (in the form of hyphae and conidia), which is the primary source of infection in the second year. The onset temperature is 20-28℃. When the conditions are suitable, bacteria multiply rapidly, producing a large number of conidia, which spread with the wind. The epidemic degree of the disease is mainly determined by environmental conditions (rain and humidity) besides the susceptibility of maize varieties.

Control measures: (1) Select disease-resistant varieties; (2) Rational close planting, increasing application of organic fertilizer, phosphorus and potassium fertilizer; (3) Should 50% wettable carbendazim be used 500 times or 800 times at the initial stage of the disease? 1000 times or 80% thiophanate methyl 800? 1000 times of liquid, 50 ~ 75 kg per mu of liquid medicine, sprayed once every 7 ~ 10 day, and controlled * * * 2 ~ 3 times.

Second, corn leaf spot disease

Symptoms: It can occur from seedling stage to later stage. From the lower leaves, brown translucent waterlogging spots appeared and gradually spread upward, especially when corn headed. After the lesion is enlarged, it is yellow-brown spindle or oval, and the edge is often reddish-brown halo. The leaves died when it was serious in the later stage. When wet, the lesion produces black villi.

Pathogenicity: Pathogens mainly overwinter on diseased plant residues, and conidia can overwinter, but the survival rate is low. The optimum temperature for mycelium development is 28-30℃, and the optimum temperature for spore germination is 26-32℃. The key period of disease epidemic in summer maize area of Henan Province is July-August, with the monthly average temperature above 25℃ and more precipitation, and the disease is easy to spread. Continuous cropping of corn has poor soil fertility, and it is easy to get sick when sowing late.

Prevention and control methods:

(1) The disease-resistant hybrid varieties are Zheng Dan No.2, Shangdan No.4 and Yudan No.6; The inbred lines are Ji 63, Liao 13 1 1, Zi 330, etc.

(2) Implement the system of crop rotation and stubble replacement to avoid continuous cropping of corn, deep ploughing after autumn, deep burial of sick and disabled, and elimination of pathogen sources. Before sowing corn, treat straw as soon as possible.

(3) Strengthen cultivation management, sow early and manage early, increase the application of organic fertilizer, topdressing nitrogen fertilizer at heading stage, strengthen field management such as intertillage drainage, and enhance plant disease resistance.

(4) Chemical control with 500 times solution of 50% carbendazim or 70% thiophanate-methyl wettable powder or 800 times solution of 90% mancozeb, 50-75kg per mu, spraying 1 time every 7- 10 days for 2-3 times.

Third, corn leaf spot disease

1. Symptoms: The ear of corn is damaged by corn leaf spot. Bracts, leaves and leaf sheaths. In order to damage the ear and cause ear rot, pathogens can reach the ear axis. The affected part turns black and sunken, which makes the ear deform and bend. The seeds turn black and dry. The diseased spots on the leaves are scattered, which are soaked, light green or light yellow spots at first, and then expand into circles or ellipses with concentric wheel lines. The middle of the lesion is light brown and the edge is brown. The diseased spots on the bract leaves were brown spots at first, and then expanded into large round spots, with concentric rings and dense black mold layers on the surface.

Pathogenesis: Because the ear is seriously ill, the seeds with bacteria play a greater role. Some infected seeds can't germinate and rot in the soil, sometimes leading to illness or death of young bacteria. The diseased plant residues left in the field or on the straw pile and the hyphae hidden in the ear can safely overwinter and become the primary source of infection in the field in the next year. In the second year, when the conditions are suitable, the overwintering bacteria will produce meristems and spread to corn plants, and germinate and invade. The conidia produced on the lesion spread by wind and rain and re-infected.

3. Preventive and control measures:

(1) Strengthen quarantine, pay special attention not to import species from epidemic areas, and choose disease-resistant varieties. Ji 63 inbred line is the most serious disease in China.

(2) Chemical control can be carried out at the peak of corn silking, with the emphasis on ear spraying. 25% triadimefon wettable powder 100g is sprayed with 50-75kg of water per mu, and generally sprayed twice every 7- 10 day.

Fourth, corn sheath blight.

Symptoms: The leaf sheaths and fruit spots that are mainly harmful to corn are round or irregular, light brown, soaked in water, the boundaries between diseased spots and healthy parts are blurred, and the diseased spots merge into larger moire patches, with light khaki or hay white in the middle and brown edges. When the humidity is high, Sheng Mao's hyphae can be seen in the ward, and then form a small white ball, which gradually turns into brown sclerotia. Sometimes obvious moire spots appear on several nodes at the base of the stem. The diseased plants have soft stems and decomposed tissues.

Occurrence regularity: Sclerotinia sclerotiorum overwinters in the soil and infects corn in the second year, which first occurs on the leaf sheath at the base of corn stem and gradually develops upward and around. Generally, the disease begins at jointing stage of maize, develops rapidly at tasseling stage, and is seriously harmful at silking and filling stage. Continuous cropping of corn leads to serious diseases; High water and fertilizer, high density, high humidity in the field, poor ventilation and light transmission, and serious diseases. There are many times of precipitation in July and August, and the precipitation is large, which is easy to induce diseases.

Preventive and control measures:

(1) Varieties with moderate leaf size and upward sloping growth, planting disease-resistant varieties, good ventilation and light transmission in the field, and light diseases.

(2) Strengthen cultivation management, rationally apply fertilizer, avoid partial application of nitrogen fertilizer, rationally discharge and irrigate, reduce field humidity and improve disease resistance. In the early stage of the disease, peeling off the diseased leaf sheath at the lower part of the corn plant can alleviate the disease.

(3) At the initial stage of the disease, spray 5% Jinggangmycin 100- 150ml, or 25g of 20% powder, or agricultural antibiotic 120 water agent 150-200ml and 50-60kg of water per mu of stem and leaf.

Five, corn head smut

Symptoms: Smut is an endemic infectious disease. It can occur in the whole growth period of maize. The aerial roots, stems, leaves, leaf sheaths and female (male) ears of maize may be damaged. The diseased tissue swelled into a tumor. The surface of the tumor is reddish in white, and then gradually turns into a gray-white to brown film. Finally, the outer membrane broke and black-brown powder was released. Usually, the tumors on leaves and leaf sheaths are small, with a diameter of only l-2 cm or less, and generally do not produce black powder. The diseased tumor on stem node and panicle is large, with a diameter of 15 cm. A corn can produce many kinds of pathological tumors. There are cystic or angular nodules in the damaged parts of male ears, and the damaged parts of female ears are mostly in the upper half. Only a few small flowers are invaded to produce diseased tumors, and others can bear fruit. The whole ear can become a 1 large tumor.

Pathogenesis: Pathogenic bacteria overwinter in soil and diseased plant residues in the form of chlamydospores. When the conditions are suitable in spring, basidiospores are produced by germination, which spread with the airflow and cause disease at seedling stage and adult stage. The suitable temperature for spore germination is 26? 30℃。 The density of maize plants is too high, and partial application of nitrogen fertilizer is beneficial to the invasion of germs at the wound. There are many bacteria sources, much precipitation, high humidity and serious diseases.

Preventive and control measures:

(1) Plant disease-resistant varieties and select local disease-resistant hybrids according to local conditions.

(2) After the corn is harvested, the straw should not be piled on the ground, but should be decomposed when composting, and the sick and disabled bodies in the field should be removed in time to reduce the overwintering bacteria.

(3) Improve cultivation measures, implement crop rotation, strengthen field management, prevent and control corn borer in time, and enhance plant disease resistance. In addition, the tumor should be removed in time before it matures and ruptures, so as to reduce the harm caused by field transmission.

Six, corn head smut

Symptoms: Symptoms appear after the male and female ears of maize head smut are pulled out. Early-growing plants, spikes and male spikes suffer, and late-growing spikes often suffer. The diseased ear is shorter than the healthy ear, and the tip is sharp, so the whole ear becomes sick, and the bracts open in the later stage, and after the internal black powder is scattered, the filamentous host vascular bundle tissue remains and looks messy. The male forest was damaged early, and the whole inflorescence became a chlamydospore mass.

Occurrence regularity: corn head smut infects/kloc-0 times a year, and there is no reinfection. Overwintering with chlamydospores on soil, fertilizer and seeds. In soil, Pleurotus ostreatus germinated under suitable conditions to produce hyphae, which were invaded by corn buds and finally entered male flowers and tassels, producing a large number of chlamydospores. Whether the soil temperature and humidity is suitable from maize sowing to five-leaf stage is the main factor affecting bacterial invasion.

Preventive and control measures:

(1) Select resistant inbred lines and plant resistant hybrids.

(2) Pull out the diseased plant and find the diseased plant. Pull them out as soon as possible. Pull them out as soon as possible, take them out of the ground and bury them deeply.

(3) Agricultural measures: implement rotation for more than 3 years in the hardest hit areas, apply net fertilizer, and fully compost and ferment straw fertilizer. Deepen the soil, strengthen the management of water and fertilizer, and enhance the disease resistance of corn.

(4) Selecting 15% triadimefon or hydroxyl triadimefon wettable powder or 50% thiophanate-methyl powder for seed dressing, and the seed dressing amount is 0.3%-0.5% of the seed weight.

Seven, corn stem rot

Symptoms: It is a disease with whole plant symptoms, and the peak of symptoms is from milk ripening to wax ripening of corn. Generally, it gradually expands upward from the lower leaves, showing bacterial wilt. Some diseased plants showed acute symptoms after the rain, and the whole plant suddenly withered. The stem base of the diseased plant becomes soft, the internal cavity is loose, and it is easy to collapse when it meets the wind. After the stem is cut open, the medulla is empty, and red symptoms can be seen at the root and stem base.

Occurrence regularity: The main infection sources of corn stalk rot in field are diseased plant residues, diseased soil and seed-borne bacteria. The overwintering pathogen invaded the human body from the root system after maize sowing to the tasseling and spinning stage, and spread and expanded in the plant. Climatic conditions from corn filling to maturity, especially rainfall, are closely related to the disease. High temperature and humidity are conducive to the onset.

Preventive and control measures:

(1) Strengthen cultivation management, select disease-resistant inbred lines, apply fertilizer reasonably, and plant densely. Enhance the disease resistance of maize.

(2) implement crop rotation to dig deep into the soil, remove diseased plants and residues, and apply the straw after full fermentation to reduce the source of soil bacteria.

Eight, corn dry rot

Symptoms: Corn can be killed in the growing period, especially in the late growing period. It hurts the stem and ears. The stems at the base and ear of the fruit are brown, dark brown and purplish red, and in severe cases, the stems fall off from the diseased parts. The rachis of diseased fruit becomes loose and easy to break, the seeds at the lower part of diseased ear turn brown and dull, and there are often white hyphae between grains, so the diseased ear is not easy to fall off when attached to bracts.

Occurrence regularity: corn dry rot overwinters on the residues and seeds of diseased plants with hyphae and conidia, and conidia are spread by airflow during the growing season of corn. High temperature and rainy weather is conducive to the infection and occurrence of pathogenic bacteria. Seed carrying bacteria is the main way of long-distance transmission. After sowing, there is much precipitation, high soil moisture, low temperature, weak seedling growth and easy to get sick.

Preventive and control measures:

(1) Agricultural measures to select disease-resistant varieties. Implement 2-3 years of rotation, dig deep into the soil in autumn, remove diseased tissues in the field and reduce the source of infection. Strengthen cultivation management, timely sowing, and increase the application of organic fertilizer. Cultivate strong seedlings and improve disease resistance.

(2) Soak the seeds with 1000 times of 50% carbendazim wettable powder for 24 hours before sowing. After soaking the seeds, rinse them with clear water and sow them. Spraying 50% carbendazim wettable powder or 50% thiophanate-methyl wettable powder 1000 times at heading stage. Spray the ear and lower stems and leaves with emphasis, and spray again every 7 days 1 time.

Nine, corn borer

Ten, corn aphids

Growing environment of maize

temperature

Corn is a thermophilic crop, which needs higher temperature during the whole growing period. The biologically effective temperature of maize is 65438 00℃. Seed germination requirements 6? 10℃, germination is slow below 10℃, 16? 2 1℃ germinated vigorously, and the optimum temperature for germination was 28? Germination stopped at 35℃ and above 40℃. The seedling stage can withstand short-term temperature dependence of -2-3℃. Need at jointing stage 15? 27℃, the flowering period needs 25? 26℃, the grouting period requires 20? 24℃。 Different maize varieties have different requirements for temperature, and early-maturing varieties in China require accumulated temperature of 2000-2200℃; Medium-mature varieties are 2300-2600℃; Late-maturing products and 25OO-28OO (3000)℃. Most corn producing areas in the world are concentrated in July, with an isotherm of 2 1-27℃ and a frost-free period of 1.20? 180 days.

illuminate

Maize is a short-day plant, which can blossom and bear fruit in short-day (8- 10 hour). Spectral components have great influence on the development of maize. According to research, corn with short-wave light such as blue light develops rapidly in the daytime, while corn with wave light such as red light develops rapidly in the morning or at night. Maize is a C4 plant with strong photosynthetic capacity and high light saturation point. Generally, the photosynthetic intensity of maize is 35-80 mg CO2/dm2? Leaves? hour

moisture

Corn plants are tall and have large leaf area, so it needs more water. The optimum precipitation during maize growth is 4 10? 640mm, drought affects the yield and quality of corn. It is generally considered that the area below 150mm in summer is not suitable for planting corn, but too much precipitation will affect the light, increase the harm of diseases, lodging and weeds, and also affect the improvement of corn yield and quality. Although corn needs more water, its relative water demand is not too high, and its transpiration coefficient is 240? 370, lower than barley (280-400), oat (340-500), purple flower Shouqing (83 1) and clover (797), and the water consumption is more economical. The root system of maize is developed, which can make full use of the moisture in the soil. When the temperature is high and the air is dry, the leaves curl upward, reducing the transpiration area and achieving a proper balance between water absorption and transpiration.

land

Corn is not very strict with the soil. Corn can be planted on chernozem, chestnut soil and sandy loam with loose soil and deep soil layer and organic matter content in the range of 6-8. Maize can grow in soil containing 0.2 1% NaCl at seedling stage, which is greater than plant death. Corn plants contain 16 elements, except for C and H2O2 from CO2. Both should be absorbed from the soil. Nitrogen, phosphorus, potassium, sulfur, calcium and magnesium are in great demand, while iron, manganese, zinc, copper, barium and chlorine are in small demand. From 10 days ago to 25? The 30-day period is the stage of the fastest accumulation of corn substances and the most fertilizer absorption, accounting for 70% of the total fertilizer absorption. 75% n，60？ The production of 100 kg corn seeds requires 75-2.22 kg nickel, 40.59-0.85 kg phosphoric acid and K2o 1.5. 1.84 kg. The ratio of the three is 2.6: 1: 2.

Efficacy and function of corn

It has the function of preventing tumors. Corn contains lysine, trace element selenium, and is also rich in B vitamins and nicotinic acid, which plays a certain role in protecting nerve conduction and gastrointestinal function, preventing beriberi and myocarditis, and keeping skin fit.

Corn also contains a lot of magnesium, which can strengthen the peristalsis of intestinal wall and promote the excretion of waste in the body.

Corn contains vitamin E. The main function of vitamin E is to promote cell division, delay aging, and to some extent alleviate arteriosclerosis and the weakening of brain function.

Corn can remove harmful cholesterol from blood and prevent atherosclerosis. The content of carotene in corn is more than five times that of soybean, and it also has an inhibitory effect on carcinogens.