Scientific Planting Of Cotton Industry Is The Direction Of Sustainable Development

The Whole Life Cycle of Cotton from a Global Perspective

Cotton is one of the most important economic crops in the world. In the past five years, the global average annual output of cotton fiber was 25 million tons, accounting for about 1/4 of the global textile fiber output. At the same time, the whole cotton industry chain has created a lot of employment opportunities, providing hundreds of millions of cotton industry practitioners with a source of livelihood.

"However, the process of cotton planting, processing and use will inevitably have an impact on the human environment. It is urgent to carry out a global life cycle assessment of cotton textiles and propose the development direction of sustainable production and utilization of cotton." Wang Zhanbiao, the corresponding author of the paper and the team's chief scientist, said in an interview with China Science Daily.

Wang Zhanbiao stressed that the cotton industry is a huge industry, involving agriculture, industry, transportation, service industry and commerce. The life cycle chain is long and complex, and each link is quite different and inseparable. "Previous studies in this area are relatively few, so it is necessary to explore the impact of the cotton industry chain on the environment, so as to help us understand the problems in the cotton industry in the environment, find improvement and innovation measures, and achieve more sustainable and environmentally friendly cotton production and use."

However, the research conducted only from the sample point or regional scale is not representative, because cotton production, processing and consumption are distributed in various regions of the world, so understanding the environmental impact of the whole cotton industry chain in the world can make the perspective more comprehensive.

In addition, there are differences in the environmental impact of cotton industry chain in different regions. Research from a global scale can compare the situation in different regions, so as to better understand the impact of different factors on the environment in various regions.

"This global perspective can provide a scientific basis for the formulation of international standards, policies and practices, so as to promote the sustainable development of the global cotton industry," said Wang Zhanbiao.

Global cotton field resource input and environmental impact

The innovation team first used the global cotton field nitrogen fertilizer input, irrigation, pesticide input and yield distribution to calculate the global cotton field resource input, and help explain why the environmental impact of the cotton life cycle is unevenly distributed in various regions.

They found that the environmental impact of cotton planting depends on the amount of irrigation, pesticides and fertilizers used. About half of the world's cotton fields are irrigated by groundwater. The average pesticide application rate is 1.57 kg per hectare, and the average nitrogen and phosphorus fertilizer input rate is 150 kg per hectare. However, the amount of irrigation, pesticide and nitrogen fertilizer applied varies greatly among cotton regions in the world: more is applied in regions with high economic development level, while less is applied in cotton regions with limited economic level and water resources.

Wang Zhanbiao said that it is urgent to improve the utilization efficiency of irrigation water, chemical fertilizers, pesticides, etc. according to local conditions and reduce the environmental impact of production links.

"Secondly, we assessed the impact of the whole life cycle of cotton on the environment from the planting stage, processing stage and use stage of cotton." Zhang Zhenggui, the first author of the paper and a postdoctoral fellow of the Chinese Academy of Agricultural Sciences, introduced that they estimated the environmental impact from four aspects: water use, human and ecological toxicity, eutrophication, and carbon footprint.

In terms of water use, 97%~98% of the water impact is related to cotton fiber production, and only 2% is related to laundry activities.

In terms of human and ecological toxicity, the toxic effects of cotton padded clothes may be mainly concentrated in the cotton planting or textile product manufacturing stage. "However, in the textile life cycle assessment, such toxicity assessment is relatively rare, because analysts face the problem of data scarcity. In addition, the methods of toxicity assessment change relatively quickly, and many research results cannot be strictly compared due to inconsistent methods." Zhang Zhenggui said.

The life cycle assessment of the impact of eutrophication shows that the highest proportion is in the sequence of chemical fertilizer application (83%), detergent use and wet processing by consumers during cotton planting.

The production of cotton padded clothes has led to carbon dioxide emissions. "We found that the carbon footprint of each product in the whole life cycle of cotton products ranges from 3 to 62 kg CO2 equivalent. In other words, every garment used will emit 50 to 872 g CO2 equivalent." Zhang Zhenggui said that the carbon footprint of garment production stage and consumer use stage is dominant. The fundamental difference has a lot to do with the source of electricity used by families and the way of washing clothes commonly used in various countries.

"According to the environmental assessment results of the whole life cycle of cotton textiles, targeted reduction of different inputs in different links is an effective means to reduce the environmental impact of the whole cotton industry chain." Wang Zhanbiao said that among all the environmental impacts they investigated, the environmental impact of natural plant fibers (cotton, jute and flax) is lower than that of animal fibers and synthetic fibers. Replacing synthetic fiber textiles with natural plant fibers is conducive to sustainable human development.

The direction of sustainable development of cotton industry in the future

Wang Zhanbiao suggested that in order to achieve sustainable development, the cotton industry needs to take a series of measures, including promoting water-saving irrigation technology, optimizing pesticide and fertilizer application, strengthening soil protection and recovery, and promoting the construction of sustainable cotton standards and certification system.

"The environmental impact mentioned in this study is different from our daily cognition, because many of them will not directly affect our daily life, but will have long-term indirect impact." Wang Zhanbiao explained, for example, washing clothes requires products such as detergent and disinfectant water, which will cause eutrophication of water after being mixed into water and discharged into rivers, lakes and seas, Finally, it circulates into human drinking water through the food chain, causing adverse effects on human health. Therefore, this slow long-term pollutant should be paid attention to.

In particular, the use stage of cotton is closely related to everyone's life. "Consumer behavior plays a decisive role in the sustainability of textiles." Wang Zhanbiao said, first of all, consumers can reduce emissions by shopping in local stores, walking or riding bicycles instead of driving, and combining shopping with other daily work.

Secondly, consumers should keep their clothes as long as possible, and advocate the concept of "slow fashion" rather than "fast fashion". At the same time, clothes that are not worn can be sold or rented to realize the circulation of clothes.

Thirdly, reducing the amount of machine wash and detergent will greatly reduce the impact of the washing process on the environment.

Finally, avoid ironing. This is also important for environmental sustainability, because ironing consumes a lot of electricity, leading to greenhouse gas emissions and, to some extent, higher eutrophication.

On the other hand, cotton is different from other staple food crops. Its production and use can exist for a long time while causing environmental impact, as a carbon fixation crop (analogous to wood).

In the planting stage, cotton, as an important cash crop, is adapted to the improvement of other staple crops. For example, improving irrigation efficiency, adopting integrated pest management, and improving fertilizer utilization are also applicable to corn, wheat, and rice fields.

Tian Liwen, a researcher at the Economic Crops Research Institute of Xinjiang Academy of Agricultural Sciences, said that the research systematically analyzed the impact of various links of the cotton industry on the environment from the aspects of cotton planting, processing and textile, providing ideas and clues for the sustainable production and utilization of cotton, and pointing out the development direction for the sustainable production and utilization of cotton industry in the future, It is of great significance to deal with the environmental challenges faced by the cotton industry and solve the sustainable development problems.