Every autumn and spring sowing season, Ma Mingxiu will shuttle in the fields. She's not busy crops sowing or reaping, but she engaged in a new career -- farmland cleaner.
Yongchang County, Gansu Province, Zhu Wang Bao Zhen Mei Nan Cun village is Ma Mingxiu, October 2015, she become the cleaners Mei Nan Cun of farmland, responsible for picking up around the village, traffic routes, channel area the waste plastic, while urging farmers timely cleaning their own waste plastic.
Such as Ma Mingxiu farmland cleaning staff, in Jinchang City, there are 234. This reporter has learned that this is an exploration of waste plastic film recycling in Gansu province. But the actual difficulties encountered a lot, not only to give Gansu a headache, the rest of the country is no exception.
In 1979, the introduction of plastic film mulching technology from Japan, followed by a large area of promotion. As of 2014, the national film to reach 1 million 441 thousand tons, covering an area of more than 300 million acres. Film role is obvious, and even can be said to be "hard work", but waste plastic produced by the "white pollution", also let many local governments and farmers scratching their heads unceasingly.
There are contradictions between production and pollution, recycling and degradation of difficult, how to alleviate the land to bear heavy, explore film "white pollution" solution, is affecting the production of agriculture and a persistent problem.
With the increase of pollution ""
Has the function of temperature raising, prevention of insect and weed suppression and mulching, has been accepted by the society. The experiment and application results also show that the technology of plastic film mulching can increase the yield of grain crops by 35% to 20%, and increase the yield of economic crops by 20% to 60%.
Up to now, the plastic film covering technology has been widely used in the country, covering crop varieties from the initial economic crops expanded to cotton, corn, wheat and rice and other field crops. According to the China Agricultural Yearbook, "the data show, flower production area northwest of corn and cotton producing areas, the northeast, North China's peanuts and cotton producing areas, northwest of tobacco and focused on producing all the vegetables is film using high strength region.
Since 2008, Gansu Province began in Eastern dry farming area innovation and R & D popularized to film application is the core of the whole film double furrow sowing technology. According to statistics, in 2015 all kinds of crops, plastic film covering area has reached 28 million 639 thousand and 200 acres, the total amount of 175 thousand and 600 tons of plastic film.
Gansu Province agriculture ecological environment protection management station vice station Li Chongxiao in "Chinese Science News" reporter the interview said, plastic film mulching technology in one fell swoop to solve the instability of grain production of historical problem, the end of the history of Gansu "party soil could not support a party", for the rainfed agricultural development to explore the successful experience for reference.
But in recent years, the wide application of plastic film covering technology has brought a series of environmental problems. In the local area, plastic film residue has caused serious adverse effects on agricultural production and environment.
Chinese Academy of agricultural environment and Sustainable Development Research Institute of biological water-saving and rainfed agriculture innovation team chief scientist Yan Changrong researcher in "Chinese Science News" reporter the interview said as the degradation characteristics of plastic film is not easy, the residual plastic film in soil will produce a series of adverse effects on soil, is mainly hampered the penetration of soil capillary water and natural water, affecting soil moisture absorption, may also reduce the permeability of soil.
Taking Gansu Province as an example, combined with the first national census of pollution sources, Gansu Province, the agricultural sector in 2008 in the province set up 12 with representative monitoring points, on the province's plastic film residue pollution carried out by field monitoring. The results showed that plastic film pollution monitoring all plots in varying degrees, residues ranged from 5.23 to 14.67 kilograms per mu.
2012, Gansu Province, the agricultural sector in the province and the 68 monitoring points in the field of monitoring. Data show that compared with 2008, per mu of plastic film residue on the whole little change, but local residual contamination has aggravated the trend, the highest residual amount has reached 17.55 kg.
It also allows, deputy director of the Institute of Gansu Provincial Academy of Agricultural Sciences of Dryland Farming Research Professor Xu Cheng Zhang sigh, the use of plastic film mulching technology is a double-edged sword, "there is risk."
Plastic film residue pollution is a new type of pollution, but also a unique type of pollution in China, the characteristics and hazards of plastic film residue is still a lack of in-depth study." Yan Changrong said.
Prevention and control of pollution sources is the key
Over the years, many local governments and farmers in the enjoyment of plastic film mulching technology to bring dividends at the same time, it has launched a fight.
In Li Chongxiao view, the use of a large number of ultra-thin film is the main cause of plastic film residue pollution. This has also been recognized by most experts.
At present, widely used in agricultural production of greenhouse film and plastic film are polyethylene blow molding products. Commonly used film thickness between the 0.08~0.14mm. Due to the large thickness, easy recovery, simply rely on market behavior, basically can can be recovered and recycled.
And the reporter in the interview to understand, the current Chinese film production standard is in 1992 to develop the "polyethylene blow molding agricultural ground covering film," the provisions of the agricultural plastic film thickness is the minimum standard of 0.008mm, but allow to float 0.003mm limit deviation and average relative deviation is less than equal to 15%.
Because the film is sold by weight, under the same covering area, the thinner the film is, the lower the cost is. "Many film production companies and distribution companies to cater to farmers to reduce the cost of demand, deliberate policy edge ball hit, ignoring the rules of national standard on film thickness and average deviation and only consider the limit deviations, coupled with for plastic film market supervision once a serious absence, thickness is 0.005 mm ultra-thin film as qualified products." Li Chongxiao said.
In fact, the film is thinner, more easily broken, artificial pick up cleaning or mechanical recovery more difficult, the higher the rate of residual farmland. "With the rising labor costs, the enthusiasm of enterprises is not high, the current recovery and utilization of residual film is not as before." Zhang Xucheng told the China Science News reporter.
Zhang Xucheng has been exploring how to reduce the use of plastic film, but also to achieve the effect of increasing production. But it is still in the experimental stage.
At the beginning of this year, Gansu Province agriculture and animal husbandry department, the trade and Industry Bureau, the Quality Supervision Bureau jointly issued the "on the cut-off ban pin disables ultrathin film of the notice", a total ban on the production, sale and use of ultra-thin plastic film in the province to strengthen waste plastic pollution prevention and control of the source, to further promote the waste plastic recycling work.
Ban production sales ban banned ultra-thin plastic film to deal with the "white pollution"?? Rong Yan believes that it is not entirely, to play a role, "prerequisite is subsequent recycling to be, otherwise thicker film will cause more serious pollution."
And the national standard of social concern is also being revised, the current draft has been issued, the new standards will soon come out." Yan Changrong said.
The "white pollution" has no nemesis?
If we can better control of plastic film pollution source, to a certain extent, to reduce the amount of pollution, but the film has been caused by "white pollution", whether there is a good way?
Previously, the practice is to recycle waste plastic recycling. In November 2013, Gansu Province pioneered the introduction of the first on the waste recycling plastic sheeting by local laws and regulations -- the Gansu Province waste agricultural plastic film recycling use regulations "will mature management experience and effective policy up to the level of laws and regulations.
According to Li Chongxiao, the Gansu Province of waste plastic film resources of use are mainly two: one is after the recovery of scrap plastic crushing, washing, through hot melting, extrusion production of recycled plastic granules, utilization of renewable particles are deep processing, production of PE pipe, plastic container, drip irrigation belt and so on; second is recycling waste plastic film without cleaning smash directly, mixing a certain proportion of slag processing to produce water well ring, manhole covers, water grate and tree grate, etc. recycled products.
In recent years, the recycling of waste plastic film in Gansu province has achieved some results. By 2015, Gansu Province 20 farmland plastic film in control monitoring data show that in 0 ~ 20cm topsoil acres of plastic film residue weight between 0~10.12 kg, and 2012 comparison has been significantly reduced.
While scientists solve the problem of pollution of residual plastic film have not been idle, the development of bio degradable plastic film the most attention.
Yan Changrong introduced to reporters, biodegradable plastic film refers to the nature of the role of microorganisms in the natural environment caused by degradation of a class of plastic film. According to the main raw materials can be divided into natural biomass as raw material for the degradation of plastic film and oil based degradable mulch film. The natural biomass such as starch, cellulose, chitin, etc., can be modified, and then the formation of biodegradable plastic film production of raw materials.
Worldwide, Europe and Japan are the most advanced countries and regions in the development and application of biodegradable materials, technology and biodegradable plastic film. At present, Japan and European bio degradable mulch film in the film market share rising has reached the 10%, a higher percentage of local application, such as Japan Shikoku area vegetable planting bio degradable mulch film ratio has exceeded 20%.
With the progress of biodegradable materials and processing technology, the application of biodegradable plastic film is more and more widely, mainly used in the field of horticulture and vegetable production.
In China, since 2010, foreign biodegradable plastic film materials R & D and production of large enterprises started and Chinese scientific research and agricultural technology promotion department cooperation in Xinjiang in the northwest, Southwest Yunnan, north of Beijing, Hebei and northwestern Gansu and Inner Mongolia of the main agricultural crops, such as cotton, corn, tobacco, potato and vegetables were test and demonstration, covering more than 10 crop, with an area of more than 2 million mu.
But this kind of product is still in the stage of experiment and demonstration, the product of tensile, and controllable degradation and increasing the soil moisture and temperature and product economy limits its large-scale promotion.
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