Attention must be paid to maize seedling raising. What chemical fertilizer should be applied?

Corn is the main autumn crop in northern China. With the beginning of wheat harvest, summer corn has also entered the sowing period. Fertilization is a very important work when sowing corn, and it is the guarantee to ensure the normal growth and harvest of corn. Don't forget to supplement trace elements while supplementing nitrogen, phosphorus, potassium and other major elements needed for corn growth.

The role of zinc

Zinc is one of the essential trace elements for maize growth. In China, 40% of the soil is deficient in zinc, especially the alkaline soil in the north. Appropriate zinc supplementation in maize can promote the formation of auxin and the synthesis of chlorophyll. It can increase the plant height, ear length and 1000-grain weight of maize, and can significantly increase the yield of maize. Therefore, when sowing corn, not only compound fertilizer but also zinc fertilizer should be applied.

Zinc deficiency symptom

Corn is very sensitive to zinc. Once zinc deficiency occurs, the leaves turn green and gray at seedling stage, and a large number of "albino seedlings" appear in the field when zinc deficiency is serious; Zinc deficiency in the middle growth stage, the lower part of new leaves is yellowish, and white or yellow tissue broadband or necrotic spots are formed between midvein and edge, commonly known as "gray leaves"; The lack of zinc in the middle and late growth period made it difficult for the female ear to stand out and delayed the silking and tasseling stage. Zinc deficiency, poor panicle development and sparse grains in the later stage led to yield reduction.

Methods of supplementing zinc

(1) Seed dressing: Before sowing corn, use 10-30g zinc sulfate per mu, add water to dissolve the general fertilizer solution which accounts for 7% ~ 10% of the seed weight, spray it evenly on the seeds, and sow in the shade. Or, the prepared solution is mixed with the seed dressing agent, evenly wrapped on the surface of the seed, dried in the shade and sown.

(2) Base fertilizer: When sowing corn, use zinc sulfate1~ 2kg per mu, mix fine dry soil10 ~15kg, and apply it to the soil before sowing or together with machine-sown chemical fertilizer.

Corn sowing technology. Select seeds

In order to improve the quality of seeds, seed selection must be carried out before sowing, and seeds with full, uniform size, bright color and high germination rate should be selected to remove chaff, rot, mildew and small seeds.

Second, seed treatment

Before sowing, dry seeds, soaking seeds and dressing seeds with chemicals can enhance germination potential, improve germination rate, reduce pests and diseases, and achieve the goals of early seedling, uniform seedling and Miao Zhuang.

1, drying seeds. Scatter the selected seeds on the dry sunny ground or mat at noon on sunny days and turn over the pile for 2-3 days.

2. soak the seeds. Cold soaking and warm soup are generally used. The soaking time is cold water 12-24 hours, warm soup (55-58℃)6- 12 hours, 25 kilograms of decomposed human urine mixed with 25 kilograms of water or biogas slurry 12 hours, except 0.2% potassium dihydrogen phosphate or trace elements12-60 hours. Note: Soaked seeds should be sown on the same day, not overnight; Under the condition of dry soil and no irrigation, it is not suitable to soak seeds.

3. seed dressing. Seeds can be dressed with pesticides such as 50% phoxim EC and 2.5ml phoxim EC per kilogram of seeds, or with trace elements such as "Oulu" brand nutrients, with 4-5 grams of nutrients per kilogram of seeds. Coated seeds do not need to be soaked and coated.

Third, broadcast early and timely, with sufficient moisture.

According to the climatic conditions in this area, early sowing is beneficial to early squatting and prolonging the growing period of corn. Wheat intercropping, 7- 15 days before wheat maturity. Intercropping late in high-yield fields and early in low-yield fields. Sowing with iron stubble, in order to realize early sowing, we should hurry to water the soles of wheat feet with water after harvest, and sowing with iron stubble with sufficient water should be completed before June 15. The sowing methods of iron stubble are ditch sowing and digging holes. When sowing, the depth should be consistent, the sowing depth should be about 5 cm, 2-3 seeds should be sown in each hole, the spacing between plants should be uniform, and the soil should be strictly covered to ensure that all seedlings can be sown at one time.

Fourth, reasonable close planting.

The reasonable density of maize is influenced by climate, fertilizer and water and variety characteristics. Generally speaking, the higher the soil fertility, the more fertilization, the higher the density of corn, and the density of short-leaf compact varieties should be higher. Wide and narrow rows can be used, with a width of 80cm and a narrow row of 40cm. The plant spacing can be determined according to the density.

Suitable planting density of Zheng Dan 958: the yield level above 500 kg is 4500 plants/mu, and the spacing between plants is 24 cm; The yield level of 400-500 kg is 4200 plants/mu, and the spacing between plants is 26 cm. The suitable planting density of Agricultural University 108: 3600 plants/mu with yield above 500 kg and spacing between plants of 30cm；; The yield level of 400-500 kg is 3400 plants/mu, and the spacing between plants is 32 cm.