In 2019, the majority of cotton farmers experienced a long period of rain, low temperature, high humidity and other natural disasters in April to June, and the development of cotton seedlings lagged behind significantly, due to the help of the heavens from July to August 10 (Shihezi Meteorological Bureau Ulan Wusu Meteorological Station forecast, As of August 10, the active accumulated temperature of ≧ 10 °C in the reclamation area was 3110.4 °C, which was 612.6 °C more than the calendar year and 438.0 °C more than last year; the active accumulated temperature of ≧ 15 °C was 2311.5 °C, which was 95.9 °C more than the calendar year and 37.20 °C more than last year; the active accumulated temperature of the ≧ 20 °C was 2077.5 °C, 431.2 °C more than the calendar year, and 276.6 °C more than last year. Recently, cotton farmers are considering and preparing to spray defoliant agricultural materials, the following talk about the use of defoliant technology, for your reference, inappropriate, please evaluate and correct.
First, the principle of spraying defoliants
Adhere to the principle of "when the silk is not equal, the time is not equal". When the cotton field cotton spit 30 to 40% or the top bell period reaches more than 45 days, you can spray the defoliant; if the time to spray the defoliant is up (depending on the temperature), even if the cotton spit is less and the bell period is lacking, it is necessary to spray the defoliant in time, otherwise, the later the time of spraying the defoliant, the lower the temperature, the worse the defoliation effect, and even the leaves cannot be taken off.
Second, the time requirements for spraying defoliant
Defoliants are very sensitive to temperature, and the defoliation effect is closely related to the temperature level. The choice of spraying defoliant time, temperature is the key, the minimum daily temperature required to spray defoliant for 3-5 days is greater than 12 °C, the daily average temperature is higher than 18 °C, and the temperature of 3 days after special spraying of defoliant is crucial. In normal years, northern Xinjiang from September 5 to September 15 (No. 15 refers to the Bole area) is appropriate, because there is more rain in northern Xinjiang, and the probability of the minimum temperature being greater than 12 °C is lower after the late and early september rains in early september and early mid-September are lower; the probability of the minimum temperature being greater than 12 °C is low; The southern Xinjiang is appropriate from September 15 to 22. Due to the large differences in region and climate, it is necessary to adapt to local conditions, be flexible and master, and not rigid dogma.
The decision-making principle of spraying defoliant time: first, it is related to the climate of the year, the temperature can be advanced when the temperature is low, and the temperature can be postponed; the second is related to the variety, the early maturing variety can be advanced, and the late maturing variety can be postponed; the third is related to the top bell period and the spitting rate of cotton, the bell period is long, and the spitting rate can be advanced; the fourth is that the area with low accumulated temperature can be advanced, and the area with high accumulated temperature can be postponed.
Third, the basic principle of the amount of spray defoiling agent
Detulon 12 ~ 16 g + ethylene 50 ~ 100 g + additives
54% thiazepene. Dichloron 15 to 25 g + Vinyl 50 to 100 g + additives
1. The appropriate amount of drug for growing normal cotton is less; the appropriate amount of cotton is too much.
2. The amount of medication for early maturing varieties is less, and the appropriate amount of late maturing varieties is more.
3. The spraying period is early and the dosage of high temperature is less; the spraying period is late and the temperature is low.
4. The amount of cotton with high density and large leaf area is moderately large; on the contrary, it is less.
Fourth, spray defoliant requirements
1, mechanical spraying defoliant: the use of hanging spray machinery, spray uniform, good atomization, small fog droplets, the amount of liquid medicine is about 40 kg, not easy to be too large, avoid loss, reduce the effect.
2, aircraft spray defoliant: because the aircraft spray defoliant liquid is small, the lower blade is not easy to spray the liquid, so the height of the aircraft is controlled at about 2 meters, so that the upper blade of the cotton is turned over, the blade application area is increased, the control operation width is wide, so that there is no leakage spray, and the spray width overlaps slightly. Spray again in 5 to 7 days to ensure the quality of the leaf removal.
3, the configuration of defoliant liquid: first of all, the defoli, ethylene, auxiliary agent for dilution, respectively, configured into the mother liquor, when the medicine box added 1/3 of the water, first add defoli agent for stirring, then add ethylene li stirring, then add additives, and finally fill up with water. Detulon additives are fast, first add the auxiliary, then add detulon, and then add ethylene.
4. Precautions: One is to avoid rainy and windy weather to spray defoliant; the second is to spray defoliant after the dew disappears; the third is to spray defoliant within 12 hours after spraying defoliant, which needs to be re-sprayed.