Cotton chemical control technology

Cotton chemical control is the use of chemical control means to shape cotton into an ideal plant type and create a population with high light efficiency.

1. Chemical control status and function

Cotton is a typical light-loving crop. High yield, early maturity and high quality of cotton in the precocious cotton area of eastern Hebei need to be achieved through reasonable close planting, but reasonable close planting will inevitably aggravate the contradiction in the utilization of space and light energy between individuals and groups in the middle and later stage. Therefore, cotton chemical control has become an important supporting measure for reasonable close planting, and it is also the core content of promoting early stress resistance, especially simplifying the cultivation technology system.

At present, thalidomide is the most widely used in cotton chemical control, and the effect is ideal. It can reduce the plant height of cotton, reduce the number of fruit branches, promote the transfer of photosynthesis to reproductive growth, reduce the shedding of cotton bolls (physiological shedding caused by malnutrition), increase the number of bolls, coordinate the contradiction between ontogeny and population development, and improve population photosynthetic efficiency. In addition, it can reduce the occurrence of insect pests, one is to lay a good foundation for spraying pest control, and the other is to improve the expression ability of insect-resistant genes, because there is a negative correlation between growth rate and resistance gene expression.

two。 Chemical control target

In order to achieve high quality and high yield of cotton, it is necessary to establish a population with high light energy utilization rate. According to the theory of synchronous cultivation, the best boll-forming position is synchronized with the best boll-forming period (rich temperature period), and the high-quality big bolls are added at 12 nodes, so as to maximize the yield-increasing potential of the population. Therefore, its management goal is to "synchronize the best boll formation position with the best boll formation period". Appropriate sowing date in advance, reasonable increase of planting density, fertilizer and water regulation and other field management all take this as the goal, and so is chemical control. Other cultivation management with the goal of "reducing Fuqian peach, increasing Fuqian peach and controlling autumn peach" and "three high synchronization (leaf high light efficiency period, cotton boll growth peak period, local light, heat and other resources high energy period)" as the goal of cultivation management, their chemical control objectives are also the same.

3. Chemical control principle

3.1 according to the characteristics of "weak in the front and prosperous after prosperity" of insect-resistant cotton and the characteristics of soil and climate in our region, it is suitable for the principle of "premise, middle control and post-prevention". Apply growth-promoting regulators such as Huafu and Lvfeng 95 at the seedling stage; regulate and control the bud and boll stage with thalidomide; after entering the boll opening stage, the root absorption function decreases and the carrying capacity is large, if there are signs of premature senility: 15% urea water can be used with 1% potassium dihydrogen phosphate foliar spraying.

3.2 principles for the use of ketamine chemical control

The principle of ① is light first and then heavy, light rather than heavy, a small amount and many times. Take the initiative to avoid excessive growth and inflexibility. This principle should be paid attention to, because cotton farmers in our region generally play thalidomide relatively late, enter the early flowering stage or start chemical control after they are found to be overgrown. ② five look (look at the sky, look at the earth, look at seedlings, look at varieties, look at the density) principle, comprehensive consideration, flexible control of chemical adjustment time and quantity. According to the weather, soil fertility and cotton growth rational control, weak seedling promotion, prosperous seedling control, general cotton promotion and control, should be cautious in case of drought. It is also important to accurately judge the growth state of cotton seedlings. For example, in June and July 2004, Rain Water was large and concentrated, when cotton grew in two states, although the leaves were yellow on the surface, one was waterlogging water control type, and the other was multi-Rain Water hairstyle. For the former, chemical control should be stopped immediately, while for the latter, time should be taken. The sensitivity of cotton varieties (lines) to thalidomide was different. For example, SGK321 special products and ordinary products are insensitive, while superior products are sensitive. The growth of different varieties is also different in each growth stage, some varieties are weak in the whole growth period, some varieties are strong in the whole growth period, some varieties are weak in the early stage and strong in the later stage, and some varieties are strong in the early stage and premature senility in the later stage. this requires careful reading of the variety profile, a detailed understanding of the characteristics of the variety, in order to facilitate flexible chemical control. The principle of combining ③ with other cultivation and management measures.

High yield is the result of the coordination of many factors. Chemical control must be combined with other cultivation measures. For example, early chemical control of fields with high cotton plant density must be coordinated with early topping; when chemical control of overflourishing seedlings in full bud stage is temporarily difficult to be effective, measures should be taken to step on cotton plants crooked with their feet and step on the other side every few days, and so on.

4. The basic mode of chemical control of acetaminophen

Taking the local soil with a density of 5000 plants / 667m ~ 2 and middle and upper fertility plots as an example, propranolol was applied four times.

4.1 Bud period (June 20-25) fine-tuning: 667 square meters with 0.51 grams of water 20 kilograms, conducive to control up and down, stable growth and bud growth.

4.2 early florescence (July 5-10): 667 square meters with 1.51 grams to 30 kilograms of water, can prevent prosperous bolls.

4.3 flowering and boll stage (a week after cotton topping, that is, about July 25) heavy control: 667 square meters with 34 grams to 30 kg of water, focusing on spraying plant crown and fruit node top, in order to shape a good plant type.

4.4 if there is a phenomenon of "running high" in the first and middle of August, it can be re-controlled: 667 square meters are capped with 34 grams to facilitate the control of late buds, shorten the upper fruit nodes, and prevent the increase of ineffective fruit nodes and superfluous buds.

The above model can be used as a reference. In the process of production, it should be mastered flexibly according to the principle of use and the actual situation.

5. Several problems related to chemical control

5.1 by using the secondary dilution method, especially in the chemical control fine-tuning in the budding stage, the actual dosage of thalidomide can be accurately grasped. Secondary dilution method: 10 grams of solid meth is dissolved in 1000 milliliters of water and diluted into 100x mother liquid, that is, 10ml mother liquid contains 0.1g of meth. When in use, add a straw to the sprayer.

5.2 meth must be a regular manufacturer's product, so as not to miss the opportunity of chemical control.

5.3 spray after the dew dries in the morning, and pay attention to the weather changes.

54 Prophase spray Dipramine, spray big do not spray small, spray high do not spray low, spray prosperous do not spray weak, spray the top of the main stem and fruit branch tip.

5.5 if overdose, cotton plant growth is slow, upper fruit branch can not protrude, plant type is too compact and dwarf, flower bud shedding rate is high, gibberellin (30-50) × 10E-6 can be sprayed or enhanced watering and fertilization can alleviate or relieve drug damage.