Green development plastic film calls for new national standard

Since the film mulching cultivation technology was introduced into China in the 1970 s, due to the realization of soil temperature control and moisture preservation, it has a significant increase in yield in arid areas, and has become a core technology of dry farming in my country. However, experts remind that the problem of plastic film pollution exposed at present should be paid attention to by all walks of life, and it is urgent to formulate more stringent national standards to solve it.

Li Fenghua, an agricultural technology expert at the Academy of Agricultural Sciences in Baiyin City, Gansu Province, said recently: "The monitoring results of the agricultural environmental protection department show that all monitored plots have varying degrees of residual film." According to statistics from the Gansu Agricultural Environmental Protection Department, in 2012, the province covered an area of 22 million mu of plastic film for various crops, and the total amount of plastic film used reached 130000 tons. About 30% of the plastic film could not be recycled and remained in the land.

The survey found that the difficult to recover the film is mainly the thickness of 0.008mm and below the so-called ultra-thin film. This kind of plastic film has poor ductility, fast aging, and some will be damaged even before the harvest season. Larger residual films can be cleaned with tools such as nail prick rake and iron fork, while those too thin and too small can only be picked up manually. In many places, the mulch is weathered into the size of a nail cover and cannot be recycled at all.

Meng Li, deputy director in charge of production and sales of Lanzhou Hongda Film Factory, pointed out: "Plastic film is sold by weight. Under the same coverage area, the thinner the plastic film, the lower the use cost, which makes ultra-thin plastic film popular in the agricultural market. According to the current national polyethylene blown agricultural ground covering film standard formulated in 1992, the minimum thickness of plastic film is 0.008mm, and the allowable deviation in the standard makes plastic film with a thickness of 0.005mm or even 0.004mm qualified for circulation."

The most effective way to ensure that farmers do not use ultra-thin plastic film is to increase the thickness of the national standard, so that ultra-thin plastic film completely out of the market. Xu Dianhong, senior engineer of PetroChina Petrochemical Research Institute, suggested that relevant national departments should consider studying and revising the national plastic film thickness standard with reference to foreign plastic film standards: "It is appropriate to raise the minimum standard for the thickness of polyethylene blown agricultural ground covering film in the existing national standard to 0.015mm."

In addition, China still has a considerable number of recycled plastic mulch on the market, waste plastic mulch made of recycled plastic mostly small factory products. Due to the low price of such products, they have a large market in rural areas, but their quality is not guaranteed, they are more likely to be damaged, have a short life span, and are more difficult to recycle, which actually further increases the environmental burden. To this end, Xu Dianhong suggested that the relevant departments of the state should withdraw the recycled plastic film from the market as soon as possible.

"The environmental protection of plastic mulch has a great impact on land quality, so the pursuit of green mulch should also become one of the development directions of the agricultural film industry." Zhu Bochao, a senior technical expert at PetroChina, said.

It is understood that the new varieties of degradable and environmentally friendly plastic films currently developed in China have covered photodegradation, photobiodegradation, photooxidative biodegradation, high starch content biodegradation, high calcium carbonate-filled photooxidative degradation, and full biodegradation. The category has played a positive role in improving the environment. As a novel green material, water-soluble film has environmental protection characteristics such as thorough degradation, safe and convenient use, so it has been widely valued by developed countries.

It is understood that with the innovation and large-scale promotion of new drought-resistant technologies, Gansu Province is currently actively practicing in policy support, mechanism innovation, and strengthening supervision, and has increased the control of waste agricultural film pollution, and the recycling of waste agricultural film has achieved initial results. For example, in addition to enjoying the support policies formulated by the province, waste agricultural film recycling and processing enterprises in the province have also received key support in terms of enterprise land, electricity, tax incentives, credit support, and project declaration. Relevant enterprises have widely set up waste agricultural film recycling outlets in villages, towns and villages through their own or development agreements to purchase large households, purchase economic persons, and mobile waste purchasing merchants (vendors), which facilitates farmers to sell waste film and effectively connects the three links of farmers' collection, network recycling and enterprise processing. The scale and scope of enterprise recycling are continuously expanding.

In view of these successful experiences, Meng Li suggested that the relevant state departments, like the recycling of waste agricultural film, give strong support to green agricultural film products in terms of policies, give key support in enterprise land use, electricity consumption, tax concessions, credit support and project declaration, set up special funds, do a good job in the promotion of environment-friendly agricultural film, and guide enterprises to make efforts in technology and product upgrading. Further promote the green transformation of China's agricultural film industry.