Tips for high-yield corn planting

Corn is a cereal crop widely grown around the world. It can not only be eaten directly as food, but also used to produce feed, industrial alcohol, biofuel, corn starch and various food additives. Learn a few tips for growing high-yield corn below.

1. Plot selection, land preparation and crop rotation strategy

1. Selection of soil conditions

When planting corn, you should choose flat land with good drainage, and avoid using long-lasting pesticides that are harmful to corn growth. The ideal soil should have a deep soil layer, good structure, a loose tillage layer and a finely broken top layer without the obstruction of the plow bottom layer.

2. Importance of crop rotation

Crop rotation is an effective way to increase yields, reduce costs and mitigate pests and diseases. Rotating corn with soybeans or other cash crops can effectively prevent and control common problems such as stem base rot, ear rot and corn borer.

3. Implementation of conservation tillage

Autumn land preparation: After the previous crop is harvested, use a stubble cutter to process the straw and return the straw to the field. Deep tillage should reach more than 35 cm, followed by raking to form large ridges 130 cm wide. It is recommended to apply base fertilizer in autumn, ensuring that the fertilizer depth exceeds 15 cm, and maintain soil moisture by compacting.

Previous crop treatment: For plots where the previous crop is corn, soybeans or other crops, the straw is crushed and scattered during harvest. Use a ground straw crusher to process the corn straw, ensuring that the straw length is less than 10 cm and evenly covers the surface. Then deep tillage is carried out to a depth of more than 35 cm, and large ridges are formed after raking, on which double rows can be planted.

4. Recommended conservation tillage methods

First, cover the surface with straw, then deep plowing and harrowing. The ridge width in autumn is 110 to 130 cm, and the ridge height is maintained at 12 to 15 cm after compaction.

Keep the soil compact enough to accommodate the development of crop roots, avoid deep loosening, harrow the ground directly to a depth of 15 to 17 cm to shred the straw, and maintain a coverage rate of about 30% on the ground to reduce wind and water erosion.

If the previous crop has been deeply plowed and the soil is loose, use a strip tillage fertilizer spreader to apply fertilizer in the autumn and clear the straw from the seedling strip to both sides. In the spring of the following year, only seeds are sown in the seedling strips without applying fertilizer.

2. Seed preparation and treatment

1. Selection of varieties

Select approved corn varieties to suit local climatic conditions.

2. Selection of seeds

Before sowing, seeds should be mechanically graded and selected to ensure uniform seed shape. Seed purity should exceed 98%, clarity should also exceed 98%, and germination rate should exceed 95%. The selected seeds should be dried for 2 to 3 days to increase the germination rate.

3. Seed processing

For plots with serious underground pest problems, you can use a seed dressing agent containing imidacloprid for seed treatment, or use clothianidin as fertilizer when sowing. In order to prevent diseases such as corn smut and stem base rot, seeds should be coated.

3. Key points of sowing technology

1. Sow early at the right time

After the soil thaws at the end of March, the autumn-raised plots are compacted to maintain soil moisture. The sowing time should be chosen when the temperature of the 5cm tillage layer reaches 5℃ stably for sowing flint corn, and when it reaches 7℃ stably for sowing dent corn. The suitable soil moisture content standard is no more than 28% for white soil and no more than 30% for black soil. Under normal temperature conditions, the suitable sowing time is from April 24 to May 10.

2. Selection of sowing machinery

Choose precision seeders from brands such as Gran, Great Plains, Maschio, Man Sheng, and Kuhn, and control the sowing speed at 6km to 8km/h.

3. Reasonable density planting

The number of seedlings of early-maturing and densely planted varieties should reach 75,000 to 80,000 plants/hm². The number of seedlings that can be guaranteed for medium-maturing varieties that are more tolerant to dense planting is 65,000 to 75,000 plants/hm². The safe seedling number of late-maturing varieties that are not tolerant to dense planting is 60,000 to 65,000 plants/hm².

4. Cultivation method

The cultivation method can be large ridge dense planting or small ridge dense planting, with the large ridge row spacing being 130cm (or 110cm) and the double row spacing on the ridge being 65cm (or 55cm).

5. Sowing and suppression

The sowing depth should be maintained at 3 to 5 cm after compaction. If sowing is early or the soil is moist, it should be maintained at about 3 cm to prevent seed pulverization or weak seedling growth. The sowing depth should be uniform and the thickness of the soil should also be consistent to ensure that the seedlings emerge in a concentrated and orderly manner. If the soil is too loose, compact it before sowing. When sowing, use the roller on the precision seeder to compact the soil. If the soil is not too dry after sowing, it is usually not necessary to compact it again. If the ridge is loose or has too much clod, it can be pressed down appropriately according to the soil moisture conditions to prevent the ridge from becoming too loose and losing moisture, while avoiding excessive pressing that may cause soil compaction.

When the soil is very humid, you should wait until the topsoil is dry to at least 1 cm before compacting it. Avoid wet compression, as it will cause the topsoil to become compacted, which is not conducive to moisture retention and seedling emergence. The air-dried soil on the surface can play a protective role. The compaction intensity should be determined according to the soil firmness and moisture conditions to avoid over-compaction, which will affect the soil temperature and root development.

4. Reasonable fertilization strategy

1. Timing of fertilization

When forming ridges in autumn, apply fertilizer into the ridges at a depth of 10 to 15 cm. Seed fertilizer is applied at the same time as sowing to provide initial nutrients.

Top dressing is applied when the corn has 6 to 8 leaves. Foliar fertilizer is applied by mechanical spraying during the seedling stage and by aerial spraying during the trumpet stage and the early stage of tasseling.

2. Amount of fertilizer

The total amount of fertilizer applied is 270 to 320 kg per hectare. If the soil is zinc deficient, an additional 5 to 10 kg of zinc fertilizer should be added. Based on the soil test results and empirical fertilization, the specific amounts of nitrogen, phosphorus, potassium and trace fertilizers to be used are determined. The recommended ratios of N:P:K vary for different soil types.

3. Fertilize in autumn

The best time to apply fertilizer is before freezing, when the temperature is stable below 10℃. The application amount of phosphorus and potassium fertilizers accounts for 50% to 100% of the total, and the application amount of nitrogen fertilizers accounts for about 30% of the total. The focus of autumn fertilization is on deep application of phosphorus fertilizer to improve its utilization rate.

4. Topdressing during jointing

When the corn has 6 to 8 expanded leaves, apply top dressing fertilizer 15 to 20 cm deep on the side of the plant, at a depth of 8 to 12 cm. The amount of topdressing is 50% to 60% of the nitrogen fertilizer used, and it should be applied by trenching with the soil covering thickness at least 6 cm.

5. Foliar fertilizer

Determine if specific nutrients need to be supplemented based on soil and plant nutrient test results. Spray foliar fertilizer 2 to 3 times to supplement the nutrients needed by the plant.

5. Key points of field management

1. Cultivation

Carry out three tillage operations, using pole teeth or a double-wing spade for the first two and a ridging spade for the last. The first tillage is done when the corn has 0 to 1 expanded leaf, the second when it has 2 to 3 expanded leaves, and the third when it has 9 to 11 expanded leaves. When tilling, be careful not to damage the roots and prevent moisture loss. Adjust the timing and depth of operations according to soil moisture and conditions.

2. Drought-fighting measures

Before corn joints, the focus is on root growth, and sprinkler irrigation is generally not necessary under drought conditions. In case of severe drought, especially during the critical period of yield formation, timely sprinkler irrigation is needed to maintain appropriate soil moisture content.

3. Chemical control to prevent collapse

When corn is in the stage of 6 to 10 expanded leaves and the plant height exceeds 70 cm, if there is heavy rain, high density or the variety has weak lodging resistance, chemical control measures should be taken. Chemical control should be carried out during the stage of 8 to 10 unfolded leaves, and avoid using it during the tasseling stage to avoid affecting pollination and photosynthesis.

6. Plant protection measures for corn

1. Weed management

Closed weeding after sowing and before seedlings:

After sowing and suppressing, spray herbicides in time, such as 90% sethoxydim, atrazine, isopropylamine, thiophanate-methyl, etc., to prevent and control annual grasses and some broad-leaved weeds. If weeds have emerged in early spring, 41% glyphosate isopropylamine saline can be used to spray the entire field, but it must be applied 4 days before corn emerges.

Precautions for soil treatment before seedling emergence:

Choose a windless morning or evening to avoid causing pesticide damage to surrounding sensitive crops. The spray volume of the sprayer should exceed 200L/hm². It is recommended to use a high-standard Teejet 110° angle nozzle to ensure uniform spraying. The application time should be as early as possible to avoid delays due to rainfall. The wind speed should be less than 4 m/s, the air humidity should be greater than 65%, and the temperature should be lower than 27°C.

Post-emergence stem and leaf treatment and weed control:

Use herbicides such as nicosulfuron, atrazine, mesotrione, pyraclostrobin, and clofopyralid. The application period should be before grass weeds have 3 leaves, broad-leaved weeds have 2 to 4 leaves, and corn seedlings have 3 to 5 leaves.

Notes on stem and leaf treatment:

Consider the safety of the pesticide on different varieties of corn. For example, pyraclostrobin is safer for corn of different leaf ages and varieties. Pay attention to the taboos of mixing pesticides. For example, mesotrione should not be mixed with organophosphorus and carbamate insecticides. Choose the appropriate herbicide according to the weed species and pay attention to the environmental conditions for application.

2. Pest control strategies

Underground pest management: Use thiamethoxam, Aimeile, and imidacloprid for seed dressing or surface spraying.

Control of gray planthopper, spotted spring and aphids: Use 10% imidacloprid wettable powder to mix and soak seeds, and spray imidacloprid solution of corresponding concentration at the seedling stage.

Sticky insect control: In mid-to-late June, if sticky insects are found, use highly effective chlorfenapyr emulsion and other pesticides for control.

Corn borer control: Use biological control such as trichogrammatids or pesticides, such as aerial spraying during the corn tasseling stage or the early stage of tasseling.

3. Disease prevention and control measures

Corn leaf blight: Spray flusilazole emulsifiable concentrate and other pesticides from the heart leaf stage to the tassel stage.

Bacterial stem rot: Pay attention to prevention and control in rainy years, spray leaf blight or metalaxyl·mancozeb wettable powder.

Smut: Prevent it through crop rotation, improving soil fertility, selecting disease-resistant varieties and proper water and fertilizer management.

Ear rot: Reduce its occurrence through crop rotation, balanced fertilization, reasonable design of planting density and timely prevention and control of pests.

7. Harvest

Choose mid-to-early maturing varieties and ensure physiological maturity, then carry out mechanical direct harvesting when the moisture content is less than 30%. When the moisture content of the grains is about 30%, they are mechanically removed from the stalks and dried in the sun until the moisture content is less than 20% to 25% before being threshed.

The above is an introduction to the key points of corn planting techniques. The specific corn planting plan should also be considered based on the climatic conditions of different regions and the selected varieties.