Comprehensive adjustment techniques for high density cultivation of cotton 81y3

Variety 81y3 has the characteristics of high boll formation rate per plant, strong boll setting, disease resistance, high yield and high quality. At the same time, 81y3 also has the characteristics of weak growth in seedling stage, stronger growth potential in bud stage, strong growth potential in flowering stage, no premature senescence in later stage and long growth period. In order to obtain high yield and high yield in a large area under the condition of high density cultivation, it is necessary to coordinate the relationship between vegetative growth and reproductive growth of cotton under the premise of scientific and rational operation of water and fertilizer, and master the comprehensive adjustment techniques of 81-3 high-density and high-yield cultivation.

I. Prophase chemical adjustment (seedling stage to early bud stage)

1. From the emergence of cotton seedlings to two true leaves, two problems need to be solved. The early sowing cotton field of ① before April 20 is easy to encounter the cold weather in late spring and early summer, which leads to the late or late emergence of stiff seedlings when newly unearthed cotton seedlings meet rain. If the soil moisture in the cotton field is too high, it is easy to cause the death of cotton seedlings. After the emergence of late sowing cotton after ② April 20, it is easy to form tall seedlings because of good temperature and light. Therefore, in order to prevent the emergence of stiff seedlings and tall seedlings, when the cotton seedlings came out neatly and the two cotyledons flattened to 4 true leaves, the cotton fields where the gravel Gobi land was too wet and the cotton seedlings grew weakly before sowing were adjusted for 2 to 3 times. for the first time, after finishing the seedlings and flattening the two cotyledons, 667 square meters were treated with 50 grams of potassium dihydrogen phosphate and 50 grams of urea to promote seedling growth. For the second time, when the cotton seedling was 2 leaves and 1 heart, 667 square meters was lightly adjusted with 0.5 grams of promethamine to promote the stable growth of the seedlings, and for the third time, when the seedlings were 4 leaves and 1 heart, 667 square meters was regulated with 1.5 grams of metropiod to promote the stable development of cotton seedlings and reduce the height of the first fruit branch of cotton. The cotton seedlings in sandy loam and loam soil were adjusted mainly by control for 2 times. For the first time, after finishing the seedlings and flattening the two cotyledons, 667 square meters were adjusted with 0.3 grams of propranolol 0.5 grams to promote the seedling to take root. for the second time, when the cotton seedlings had two leaves and one heart, 667 square meters were adjusted with 0.6 grams of thalidomide to promote the stable growth of seedlings. For the third time, when the cotton seedling was 4 leaves and 1 heart, 667 square meters was regulated by 1-1.5 grams of metropiramine to promote the stable development of the seedling and reduce the height of the first fruit branch of cotton.

two。 When the cotton seedlings grew to 5 or 6 true leaves, the growth potential of cotton plants increased gradually. In this stage, in order to ensure the development of cotton seedling root system and leaf emergence speed, and make the cotton seedling grow steadily, the 4th trimethylamine adjustment was carried out, 667 square meters with 2 grams of promethamine. In order to ensure that the chemical adjustment is in place, the four chemical adjustments from seedling stage to early bud stage are all mechanical ones, with an interval of 7 to 10 days.

Second, mid-term adjustment (bud stage to early flowering stage)

In order to ensure the transition from vegetative growth to reproductive growth from bud stage to early flowering stage, comprehensive control measures such as fertilizer and water regulation, contractile amine regulation and cotton topping and pruning were mainly adopted. The daily growth index of cotton plant at this stage: the daily growth of cotton plant is less than 1 cm before drip water and less than 1.5 cm after drip water, which should be maintained until cotton topping. When the first flower of cotton blossoms, the plant height is controlled at about 40 cm and the leaves are medium. In this stage, two or three times of acetaminization control was carried out. The first time was one or two days before dripping water on June 10. In gravel Gobi or cotton fields with serious drought, 667 square meters were lightly adjusted with 0.5 grams of propionate. Cotton fields with normal growth of cotton seedlings in sandy loam and loam land were mechanically adjusted with 1.5 grams of propionate 3 days before drip water. For the second time, when cotton entered the full bud stage to early flowering stage, the main purpose of chemical control was to prevent hollowness, alleviate the contradiction between individuals and groups, promote the transport of cotton nutrients to buds and bolls, and improve the structure of buds and bolls. The chemical control of the early flowering stage is generally before the second water, that is, June 18-20, generally 667 square meters with 1.5 grams of metoprolol. The third chemical adjustment is before the third water before cotton topping. From June 30 to July 2, this chemical control has the effect of preventing the prosperous growth caused by hollow and cotton fields after entering water in time. According to the seedling growth situation, the dosage of 667 square meters of propranolol is 1: 1.5 grams.

Third, late chemical adjustment (flower and boll stage)

1.81Y3 has the characteristics of strong growth in flower and boll stage, no premature senescence in the later stage and inverted tower-shaped plant. in order to prevent the three fruit branches at the top of the cotton plant from growing too fast, concealing and shading the cotton plant, resulting in falling flowers and bolls, the capping was carried out in time after topping, and the effect of capping twice was good. The first capping was carried out on the 3rd day after topping, and 667 square meters were capped with 667 square meters. For the third time, within 7-8 days after topping, 667 square meters were reused with 4-6 grams of propranolol. The chemical adjustment after hitting the top should pay attention to two points: first, the time should not be too late, generally two times in 8-10 days to end the capping; second, the amount of ketamine should be accurate.

2.81Y3 has the characteristics of more bolls per plant and high boll formation rate. In the first and middle of August, 150 grams of potassium dihydrogen phosphate + 100 grams of urea + 2 grams of brassine were sprayed on 667 square meters of leaves for 2 to 3 consecutive times to nourish roots and protect leaves and increase boll weight.

In the comprehensive chemical regulation techniques for high-density cultivation of 81y3 varieties, chemical adjustment should be given priority to in the early stage and fertilizer and water control in the middle and later stages, with fertilizer and seedlings developing early and steadily, growing steadily in the middle and slow growth in the later stage, and the combination of promotion and control, so that cotton can grow steadily during the whole growth period, the plant height is suitable, the bolls in the middle and lower parts are good, and the top is not empty. In the first and middle of August, there are many bolls, not flourishing and not early aging, so as to achieve the goal of stable yield and high yield.