What happens to film-free cotton? The film not only increases the yield of cotton but also brings "white pollution."

The main cotton planting area is almost "no film and no cotton"

Cotton must cover the mulch, which seems to have become common sense. As soon as the cotton planting season is reached, farmers’ friends buy plastic film early, and technicians will also give instructions on the spot.

Covering the mulch film can increase temperature and protect the weeds, inhibit weeds, prevent pests and disease, keep water and protect fertilizers... In the cotton planting areas of northwest, northeast and north China, almost no film and no cotton.

Xinjiang is the most important cotton-producing region in the country. The cotton planting area in southern Xinjiang alone amounts to 20 million mu, accounting for about two-thirds of Xinjiang. Since the 1980s, Xinjiang has widely promoted the use of plastic film mulching technology in cotton planting, which has greatly increased cotton production, which has brought huge benefits to Xinjiang's agricultural production and farmers' income.

However, cotton farmers have a complex complex of mulch film: bringing about increased production, but it has also become the culprit of "white pollution" in cotton fields.

Tang Huajun, president of the Chinese Academy of Agricultural Sciences, said that in the past 30 years, China's mulch coverage and use has been ranked first in the world. Among them, the amount of film used in Xinjiang is second to none.

“Using mulch film can increase crop yield by 20%-30%, and large-scale promotion promotes cotton production in Xinjiang. For cotton production in Xinjiang, the use of mulch film is indeed a great 'revolution'.” Deputy Department of Plantation Management Department, Ministry of Agriculture Chang Yang Lisheng said.

However, as time went by, the film residue finally revealed its awkward side.

“With the increasing use of mulch film and the low recovery rate of residual mulch film, the amount of residual film in the soil is gradually increasing, the soil structure is seriously damaged, and the quality of cultivated land is gradually decreasing. Nowadays, Xinjiang has become one of the areas with serious residual film pollution. "Yang Lisheng said.

According to the research report, when the amount of residual film in the soil reaches 3.5 kg per mu, cotton will reduce production by 11.8%-22%. Moreover, if the seeds are sown on the residual film, the rate of rotting and germination rate will be greatly increased.

Residual film contamination can also affect the quality of raw cotton. Yu Shuxun, an academician of the Chinese Academy of Engineering, said that for machine-picked cotton, the residual film will be mixed with cotton with machinery, which constitutes the “new force” of cotton “three-wire” pollution. This will have a major impact on the quality and dyeing of cotton.

Mao Shuchun, a researcher at the Cotton Research Institute of the Chinese Academy of Agricultural Sciences, said: "The residual film is in the 0-30 cm underground layer and is excavated." He said that the treatment of farmland residual film pollution "to an imminent moment" because of pollution The continuous accumulation of quantity will not only affect crop yield and quality, but also have a great impact on the ecological environment. Therefore, reducing the use or not using the mulch film has become an urgent need for the development of crop cultivation such as cotton in the future.

In order to get the residual film out of the farmland, agricultural experts have tried many methods. Yang Lisheng introduced that a large number of researchers have made great efforts in the aspects of mulch degradation and residual film recycling.

Since 2012, the state has implemented agricultural clean production demonstration projects in Xinjiang, and has carried out comprehensive management of wasteland mulch pollution in 46 counties and cities in Xinjiang. From May 1, 2016, Xinjiang officially implemented the regulations on farmland mulch management, which not only refused to produce ultra-thin film production and sales, but also required 100% recycling of used film.

Technology allows cotton to be covered without film

It is natural to rely on science and technology to solve the "white pollution".

At the end of September 2017, in the expert workstation of the Shaya Academician of the Chinese Academy of Engineering in Shaya County, Xinjiang, the 50-mu film-free cotton test field was covered with cotton blossoms of white flowers.

According to the on-site experts, Yu Shuxun led his research team to realize the filmless planting of cotton through experiments and demonstrations in southern Xinjiang for 7 consecutive years.

Cotton is not covered with mulch, which seems to the cotton people to be a fantasy. But the truth is the most convincing! After on-site inspection and production measurement by experts, the number of bells in the demonstration area reached more than 70,000, the average yield per mu was over 365 kg, and the yield per mu of high-yield land was 400 kg, which was equivalent to the yield of large-area cultivated cotton, showing early maturity and high yield. Characteristics. As evaluated by third-party scientific and technological achievements evaluation agencies, this technology has innovated a technological approach with subversive potential to completely solve the residual film pollution in cotton fields, and the key technologies have reached the international leading level.

It turns out that when cotton is planted, it will often encounter low temperature and cold damage, which directly affects cotton emergence. In the autumn harvest season, bad weather such as low temperature frost will also affect cotton yield and harvest. In response to these problems, Yu Shuxun exerts the advantages of his own research team in breeding, and conducts joint experiments and collaborative research with relevant scientific research units and enterprises. From the selection of new varieties, he has cultivated the “Zhongmian 619” with late sowing and early maturing varieties.

The reporter learned that "Zhongmian 619" can be planted for more than 10 days in the evening, just to avoid the low temperature when planting in spring; because of its precocious characteristics, it has subtly avoided the bad weather such as low temperature frost that may be encountered during autumn harvest. . Through these characteristics, the goal of cotton planting no longer needs to cover the mulch film is realized.

In southern Xinjiang, cotton is grown without film, and the emergence rate and seedling rate are the key factors determining whether it is feasible. "Zhongmian 619" is produced by high-yield, early-maturing, salt-tolerant, low-temperature-resistant four-parent polymerization hybridization. It has the advantages of special early maturity, salt and alkali resistance, low temperature resistance, etc. It is suitable for large temperature difference and salinity. No long-term sunshine in the southern Xinjiang region.

"Zhongmian 619" has a growth period of about 120 days under the condition of non-membrane cultivation in southern Xinjiang. Compared with the mulch covered cotton, it can be postponed for about 10 days, which can effectively avoid the damage of cotton caused by cold damage in early spring. The characteristics of salt-tolerant and low-temperature resistance allow the variety to sprout quickly under the condition of no film covering. The emergence rate and seedling rate have no significant difference with the emergence rate and seedling rate under the film-covering conditions. Cotton yield is affected by emergence rate and seedling rate.

Experts from the research team of Yu Shuxun introduced that in order to realize the comprehensive technology of membrane-free cotton, aiming at the no-film planting and growth characteristics, using the precision seeding technology to realize the whole seedling, the management process of the seedlings and seedlings can be omitted; The picking device avoids the blockage of the hole hopper due to the lack of film covering; for effective heat preservation, water retention, and moisture retention, the seedling rate and seedling rate are further enhanced, and the seeding depth of the hole spreader is increased to 3.5 cm (0.7 cm deeper than the film cotton) At the same time, the drip irrigation belt is buried shallowly under the soil by 2-3 cm to realize the fixed and effective irrigation of the drip irrigation belt to avoid wind damage. According to the growth of the film-free cotton field, the planting density was appropriately increased, and the number of plants per hectare increased by 45,000, which reduced the amount of drug while ensuring cotton yield, saving cost and protecting the environment.

Collaborative innovation can go further

“Last year, affected by the continuous rainy weather during the seedling period, the emergence rate is only about 75%. If the emergence rate can be increased by 10%, the output can be increased a lot.” A person in charge of the Xinjiang Shouxin Seed Industry Co., Ltd., who is responsible for the demonstration field management, said.

The highest yield of high-yield cotton in the same area can exceed 500 kg per mu. In contrast, the production of the film-free “Zhongmian 619” is slightly inferior. However, in Mao Shuchun's view, the production of more than 350 kilograms of seed cotton by filmless planting is “not already low”.

“According to 41% of clothing, the yield of lint per acre is about 150 kg, and the output is basically guaranteed.” Mao Shuchun believes that the output is lower than the film cotton field, but more importantly, how to balance the ecological benefits. And economic benefits. From the comprehensive evaluation point of view, the filmless cotton plant has already opened a good start.

Nevertheless, there are still many problems to be solved if the film-free cotton is to be promoted.

“No-film cotton planting has raised many new problems for scientific research and production. For example, how to solve the problem of dead seedlings and breeding of herbicide-resistant varieties; in addition, the seeding technology of non-membrane cotton, fertilizer and water regulation, etc. need further optimization, and there are still future A lot of work has to be done.” Mao Shuchun said, “The new agricultural technology must be carried out steadily from pilot to demonstration and promotion. It must be step by step.”

Yu Shuxun also said that the film-free cotton is only a staged result. In the future, while grasping the output, we must also consider the quality. “Especially in breeding, synergy is needed to go further.”