The Correct Way to Return Corn Stalks to the Field: A Must-Read for Farmers

With the further promotion and use of full mechanization in corn production, corn stalk return-to-field technology has become increasingly popular among farmers. Compared with traditional tillage methods, stalk return-to-field eliminates the steps of snapping off the ears, cutting the stalks, transporting the ears, moving the stalks, and removing the roots, and can also significantly increase soil fertility, improve soil structure, raise agricultural production efficiency, and reduce environmental pollution. However, if the supporting techniques are not done properly, corn stalk return-to-field can also cause three fatal harms to the following crop of wheat.

1. Causes yellowed and weak seedlings

After corn stalks are returned to the field, the nutrients in the stalks cannot be directly absorbed and used by crops; they must first be decomposed by microorganisms. The carbon-to-nitrogen ratio suitable for soil microbial activity is 25:1 to 30:1, while the carbon-to-nitrogen ratio of corn stalks is 80:1 to 100:1. If the soil is deficient in nitrogen, the microorganisms will compete with the wheat for nitrogen, causing yellowed and weak seedlings due to nitrogen deficiency in the wheat.

2. Causes missing seedlings and broken rows

Returning large amounts of corn stalks to the field makes the soil loose and increases the gaps, making it difficult for seeds to come into close contact with the soil, which affects seed germination and emergence and leads to missing seedlings and broken rows.

3. Aggravates pests and diseases

Corn stalks often carry large amounts of pathogens and insect eggs, which cannot be killed during the direct chopping process. After being returned to the field, they remain in the soil, causing farmland pests and diseases, especially soil-dwelling pests, to worsen year by year and harming the normal growth of wheat.

With corn stalk return-to-field, by mastering the following supporting measures and controlling the key indicators well, these harms can be avoided.

1. Ensure the quality of stalk chopping and control the return quantity

Adjust the machine properly; the chopped length of corn stalks should preferably be 3-5cm, so that the stalks are not too long and the soil cannot be pressed firm, which would affect crop emergence and growth.

Returning stalks to the field is not a case of the more the better; the return quantity should be determined according to water sources and tillage conditions (the general standard is preferably 400-500kg per mu). In principle, it should ensure that the stalks returned that year fully decompose and do not affect the tillage quality of the following crop.

2. Plow or rotary till as early as possible, and compact the soil after sowing

After the stalks are chopped, they are evenly spread in the field. At this time, the stalks should be plowed into the soil as soon as possible, generally to a depth of 20-30cm. It is best to plow and bury them while harvesting, ensuring that the chopped stalks and soil are fully mixed and that there is no obvious accumulation of chopped stalks on the surface, so as to facilitate stalk decomposition and ensure wheat seed germination and emergence.

When sowing wheat after stalk return-to-field, the seeding rate should be appropriately increased by 0.5~2 kg above the normal rate. After sowing, the soil must be compacted, especially in rotary-tilled wheat fields. It is best to compact while sowing so that the seeds come into close contact with the soil, ensuring sufficient basic seedlings.

3. Apply more nitrogen fertilizer and guard against carbon-to-nitrogen ratio imbalance

The carbon-to-nitrogen ratio of corn stalks is 80:1 to 100:1, while the carbon-to-nitrogen ratio suitable for microbial activity is 25:1 to 30:1. For wheat with stalk return-to-field, more nitrogen fertilizer should be applied in the base fertilizer; choose a wheat compound fertilizer with a slightly higher nitrogen content as the base fertilizer. Alternatively, on the basis of normal wheat fertilization, apply an additional 5~7.5 kg of urea to meet the nutrient needs of the wheat and microorganisms and to speed up stalk decomposition and rotting.

4. Improve soil moisture and ensure return-to-field with sufficient moisture

Soil moisture status is an important factor determining the speed of stalk decomposition, because stalk decomposition depends on microorganisms in the soil, and the survival and reproduction of microorganisms require suitable soil. If the soil is too dry, it will seriously affect the reproduction of soil microorganisms and slow down the speed of stalk decomposition.

It is better to sow appropriately late than to lack sufficient subsoil moisture; create enough subsoil moisture and sow with sufficient moisture to ensure full seedling emergence in one sowing. If moisture is insufficient after sowing, you can also promptly irrigate with a light surface watering. Check and replant seedlings in time. Winter irrigation should be early and the water volume should be small; after watering, promptly carry out intertillage and hoeing to break up surface crusting.

5. Remove diseased stalks and do a good job of soil and seed treatment

1. Remove diseased stalks:

Diseased stalks cannot be directly returned to the field; otherwise, if corn is planted in the summer of the following year, diseases are likely to occur. Such stalks should be destroyed or composted at high temperature before being applied to farmland.

2. Soil treatment:

Before rotary tillage or deep plowing, broadcast per mu 3-5 kg of 3% phoxim granules or 3% phorate·phoxim granules and 2-5 kg of quintozene wettable powder. Or dilute 500 ml of 48% phoxim emulsifiable concentrate with 1-2 kg of water, mix it with 20-25 kg of fine sand or fine soil, then mix it with 2-5 kg of 70% thiophanate-methyl wettable powder, and evenly broadcast it on the ground and turn it into the soil by deep plowing or rotary tillage, so as to prevent and kill soil-borne disease and insect sources and insect eggs in the soil and achieve the purpose of pest and disease control.

3. Do a good job of seed treatment:

It is best to buy coated seeds, or carry out chemical seed dressing. Insecticides should be applied first, then after piling and covering for a while, fungicides should be applied; after drying, sowing can be carried out. Seeds already treated with fungicide should not be stored for long. In areas with severe occurrence of soil-dwelling pests, chemical soil treatment should be used.

Stalk return-to-field is actually a very good method of stalk treatment, but everyone should note that the return-to-field techniques must be mastered well; otherwise, it will be counterproductive and unfavorable to crop growth.

The above are the stalk return-to-field methods and precautions shared by the editor. I hope they are helpful to all growers.