Overuse of fertilisers and pesticides is causing pollution and food safety problems. What’s more, Chinese agriculture has now become reliant on these chemicals.
“If China used one half of the fertiliser it used currently there wouldn’t be any problems,” said Zheng Fengtian, a professor at the School of Agricultural Economics and Rural Development of the Renmin University of China in Beijing.
How bad is the overuse of fertiliser on Chinese fields? Figures from the Chinese Academy of Agricultural Sciences’ (CAAS) Soil and Fertiliser Institute show that in one-half of Chinese regions, average levels of nitrogen fertiliser use exceed the internationally accepted limit of 225kg per hectare.
Alongside overuse there is misuse, which lowers uptakes rates – only 30% of the fertiliser China applied actually does any good, much lower than the 40% rates in Western nations. A survey by agricultural authorities in Henan found that only one-third of the three million tons of fertiliser used in the province was actually absorbed by crops.
The unused fertiliser causes pollution. A CAAS survey of intensive vegetable farms in 20 counties in five northern provinces found that half of 800 points surveyed had excessive levels of nitrates in ground water attributable to fertiliser. CAAS predicted that all central and south-eastern provinces bar Jiangxi and Shanxi were at high risk of suffering groundwater nitrate pollution by 2015.
Experts say misuse of pesticides is reaching a tipping point. Huang Hongxiang, a researcher at CAAS’s Institute of Agricultural Resources and Regional Planning, said that year-round planting requires the large-scale use of pesticides and fertiliser and this inevitably creates soil and water pollution. That in turn means even more fertiliser and pesticides are needed, creating a vicious cycle.
China’s reliance on fertiliser
Could China ever live without fertilisers? It’s a tough question. Huang Hongxiang said that fertiliser is overused in pursuit of bigger harvests. High yields require plenty of nutrition, but China’s soils are not particularly fertile and need extra nutrients. Fertiliser is the most direct way to provide these. “If less fertiliser is used harvests will decrease, and that will impact on the food security of 1.3 billion people.”
In 2011 China’s grain harvests passed the 1.1 trillion kg mark, achieving the first eight years of successive growth in half a century. Harvests have been at more than 1 trillion kg for five years in a row and are already at the level originally planned to be reached in 2020.
Despite this success, Zhang Yang of the Central Rural Work Leading Group Office stressed that “production of grains and other important agricultural products is not stable and there are still supply and demand issues,” At the same time, he said that “currently China’s agricultural and rural ecosystems are vulnerable. Soil and water are being lost, the land is degrading, crop diversity is falling, natural disasters are frequent, and the excessive and inappropriate use of fertiliser and pesticides mean that both farms and villages are badly polluted. Agricultural and rural pollution will cause a range of problems, including with food security.”
Copying the US-style farming system
China claims an agricultural culture stretching back five millennia. But while in the past this culture worked in accordance with nature, now everything relies on chemicals.
Zheng Fengtian explains that current methods are heavily influenced by the US: “In the past a rural family would keep cows and use dung as fertiliser, with chemical fertilisers rarely used, which was good for the environment. But now very few cows are kept, as weedkillers have killed off the grass they eat. Many farmers have gone to the cities to work, with agriculture now mechanised and relying on fertiliser and pesticide, which ruins the soil. It’s a big problem.”
“It’s an exploitative method of production,” says Huang Hongxiang. “China has a huge population but little arable land, so infertile land is often used. To increase yields fertilisers are added and the soil is turned frequently to release nutrients. In comparison with soil at other points at the same latitude, Chinese soil lacks nutrients.” The less nutrients in the soil, the more farmers will apply fertiliser and use pesticides.
Xu Ming, director of the Pollution Prevention Office at the Ministry of Agriculture’s Agro-Environmental Protection Institute, says industry and mining are largely to blame for heavy metal pollution. But monitoring has also found that the arsenic and mercury in bactericides used in the past can accumulate in the soil.
“Farmers use these chemicals as they feel like it, or as they always have,” says Xu. “The Ministry of Agriculture has standards for use, but if the standard says to use one bottle cap’s worth of pesticide the farmers will use three, just to make sure. But that’s just a waste.” In more closely regulated nations farmers aren’t allowed to apply pesticides themselves – certified companies need to be used. Although there are agricultural technology offices in China’s villages, there’s no way to monitor what the individual farmers are doing.
The excess fertilisers and pesticides are carried into the rivers, resulting in eutrophication (a process where too much nutrient in the river causes excessive plant growth and starves fish of oxygen). For years algal tides have plagued ecologically-important lakes such as Taihu. Xu Ming believes that this is related to phosphates in fertiliser used on rice fields around Taihu.
What makes the issue more serious is that Chinese agriculture is already reliant on these chemicals. Before 1979, farmyard manure was used as fertiliser and water pollution was very rare. Now if chemicals weren’t used yields would drop and plagues of insects would appear. “It’s become a natural phenomenon. The farmers know when to apply the pesticide. With green veg and Chinese olives if you don’t apply pesticide the whole lot gets eaten by insects,” says Xu.
Economic factors push farmers towards using more chemical pesticides. Although biological pesticides have a lesser effect on the human body, they are not as effective and are more expensive. 500ml of biological pesticide may cost one hundred yuan – the chemical equivalent something over ten yuan, and it kills the insects immediately. The farmers don’t want the extra expense, so there’s no market for the biological alternative.
Even organic fertilisers aren’t safe enough. Huang Hongxiang explains that chemical fertilisers have an effect on the soil and the environment, and affect the quality and taste of crops – but they are not in themselves toxic. “It’s actually the organic fertilisers that are the worry. In the past pigs and chickens were fed on grain, but now pig fodder might contain antibiotics and hormones, while chicken fodder can contain a range of chemicals. The use of their manure on crops could present a new risk itself.”
A Soil Pollution Prevention Law, aimed at legislating for the use of fertilisers and pesticides and preventing soil pollution, has long been in the works. But there is still no sign of it actually appearing.
Yang Meng, Beijing reporter
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