Can Tianjin still grow corn after the shock?

Maize can be planted in Tianjin area after being shocked, and the yield of spring maize (65438+1October 25th-February 10) is the highest. Followed by autumn planting (August 25-September10); Plant again in winter (65438+1October 20th-65438+1October10); The last broadcast was in summer (April 25th-May 10). In a word, the best sowing date of corn should be determined according to the use of corn, land use and stubble arrangement. Forage corn is suitable for planting in spring and autumn.

1, seedling management

Maize seedling stage is a vegetative growth period formed by rooting, leaf differentiation and stem, node and leaf differentiation, when most roots are formed. The main goal of seedling management is to promote root system development, cultivate strong seedlings, achieve complete, neat and strong seedlings, and lay a good foundation for the growth of panicle and grain stage.

(1) Fixed seedling spacing: Master the principle of "removing the weak and retaining the strong, keeping secret and sparse, orienting, ensuring uniformity and ensuring strong seedlings". Generally, seedlings are fixed when there are five true leaves, and one strong seedling is left in each hole. At the same time, check the replanting, transplanting seedlings with soil, and pouring enough root water to ensure the survival of seedlings. If there are too many seedlings, it can be solved by replanting.

(2) Intertillage and weeding: Corn can be intertilled for 1-2 times at seedling stage, combined with fertilization and proper soil cultivation. The depth of intertillage should be shallow beside the seedlings, deep between rows, shallow before the seedlings are fixed and deep after the seedlings are fixed, and attention should be paid to pest control.

(3) Water and fertilizer management: Apply seedling fertilizer for the first time when the leaves are 5-6, with 7.5- 10 kg of urea per mu, furrow in the center of the border, and then cover the soil. If there is water shortage at seedling stage, irrigation should be carried out in time, and furrow irrigation is appropriate. In rainy days, wet soil and stagnant water, we should pay attention to open deep ditches to drain stagnant water and improve soil ventilation conditions.

2. Heading date management

The goal of field management at panicle stage is to attack stems and panicles, prevent water shortage and fertilization, and make plants neat, stem nodes short and thick, leaves wide and thick, roots thick and big, and male and female panicles develop well.

(1) Water and fertilizer management: When the leaves are 8-9, the second topdressing is applied, that is, the straw fertilizer is applied. The amount of fertilizer applied this time is about 25% of the total amount of fertilizer applied. Compound fertilizer 10 kg and potassium chloride 7.5 kg are applied per mu, and the fertilization method is strip application. 14- 15 leaf stage (big trumpet stage) was applied for the third time, that is, the fertilization amount was about 35% of the total fertilization amount, 20 kg of compound fertilizer was applied per mu, and potassium chloride 10 kg was combined with large soil cultivation. 9 leaves, 15 leaves, topdressing outside the roots once, spraying 50 grams of rare earth or 800- 1000 times of potassium dihydrogen phosphate per mu. From jointing to heading, maize plants began to grow vigorously and needed a lot of water, especially before and after heading. At this time, corn needs a critical period of moisture, which leads to water shortage, poor development, disharmony between male and female flowers, which affects pollination and leads to baldness, lack of grains or empty stalks, so the soil moisture content should be kept at 70-80% during this period. Pay attention to ditching and drainage in rainy areas. The damage period of corn borer is from trumpet stage to heading stage, and trichlorfon should be sprayed 500-800 times or mixed with Bt powder to control corn borer.

(2) Ridge cultivation: In order to prevent soil hardening, eliminate weeds, improve the growth function of roots, and promote multiple deep roots of roots, ridge cultivation should be carried out according to the soil and weeds at the heading stage. Generally, intertillage for 1-2 times before jointing to heading, and intertillage for 2-4 inches deep between rows, so as to cut off part of hairy roots, stimulate multiple new roots and enhance the ability of drought resistance and lodging resistance. Before heading, shallow intertillage and ridging shall be carried out at the "big bell mouth" stage 1 time.

3. Heading and fruiting period management

This period is the key period to determine the effective panicle number, the number of seeds per panicle and the grain weight. At this time, the main work is to supplement fertilizer (urea 10 kg), drought-resistant drainage, artificial pollination and so on. Irrigation should be done in time when heading, flowering and filling to keep the soil moist and meet the requirements of plants for water. However, irrigation should not be over water, and it is better to irrigate horses. Pay attention to drainage in rainy days to avoid water accumulation and lack of oxygen to hurt roots. In the flowering period of maize, in case of bad weather, artificial pollination should be carried out for 2-3 times, usually at 9- 1 1 on sunny days, which can reduce grain deficiency and baldness.