China pollutes water sources because of 'chemical dependence'

To ensure sufficient food for a population of more than 1.3 billion people, China must strongly use chemical fertilizers to increase crop yields. And the consequence is the heavy water pollution that this country is facing.

The price for the world's No. 1 position in grain production

Image for illustrative purposes. (BBC Source)

China owns only 9% of the world's total arable land, but must feed 21% of the global population, while most of the land is not very fertile.

In the past three decades, in order to make up for the huge gap between capacity and demand, China's agricultural industry has viewed chemical fertilizers as a stimulus for output.

In 1980, nearly 80% of China's arable land contained phosphate below 10miligram / 1kilogram of land, meaning that it was in short supply. Then, due to the Government's incentive policies, the amount of phosphate used has increased by 5% annually.

Since then, the amount of this chemical accumulated in the soil in China has reached 85 million tons. In the last year alone, the amount of phosphate consumed by Chinese farmers amounted to 11 million tons, accounting for 35% of global production.

Chemical fertilizers have yielded spectacular results for Chinese agriculture. From the 1960s until now, grain production in China has increased 8 times and now accounts for 24% of the world's production.

But besides, China also became the world's largest fertilizer consumer. Many environmental experts have even used the concept of "addiction" or " dependency " to describe the abuse of chemical fertilizers in China.

Renmin University research published earlier this year shows that Chinese farmers use 40% more fertilizer than necessary and as a result, about 10 million tons of waste are discharged directly into the water every year. .

According to a report by the Chinese government, chemical fertilizers are the second cause (after breeding) causing excess phosphorus in the water, leading to the explosion of toxic algae in many rivers. , lake.

Overgrowth of algae (which, from a specialty called eutrophication) significantly reduces dissolved oxygen in the water, kills fish and aquatic plants, and can release toxic toxins affects people and pets.

How to save Thai Ho?

A typical example of eutrophication is Thai Ho, a famous natural wonder of China. Since 2007, about 1/3 of the lake surface began to be thickened by green algae and cyanobacteria.

Thai Ho was invaded by toxic algae.

The analysis of 25 water samples conducted by Hoa Binh Xanh showed that 20 samples with nitrogen and nitrate concentrations (components of chemical fertilizers) can be dangerous for humans. A study published by the China Institute of Geography and Natural Resources last month clarified the cause of this phenomenon.

Accordingly, the amount of fertilizer flowing by water to Thai Ho from surrounding agricultural lands is up to 6kg / 1ha, 6 times higher than the alarming level in developed countries. It is not surprising that Taihu Lake and many other large Chinese lakes such as Chaohu (Anhui Province) and Lake Tian (Yunnan Province) are invaded by algae.

When the toxic algae incident in Thai Ho happened, the local authorities announced spending $ 14 million to clean up the environment. But after 3 years, the progress has not yet met expectations.

Earlier this year, it was decided to release about 20 million algae-eating fish into the lake. But according to the study, the goal of improving water resources in Thai Ho as well as the area being occupied by algae will not be effective, if it cannot stop from the root.

Renmin University's report recommended that the Chinese government reduce 50% of chemical fertilizers used in agriculture, limit subsidies for producers of chemical fertilizers, but instead encourage farmers to use Use animal waste as fertilizer. If all manure is used, Chinese farmers can reduce 3.3 million tons of phosphate, nearly 1/3 of the current consumption.