Overuse of nitrogen fertilisers in China is leading to rapid soil acidification and is causing lasting damage to ecosystems, according to soil study
Nitrogen fertilisers used to increase crop yields in China are having “extreme” environmental consequences, according to a study from leading soil scientists.
Scientists from China, the UK and the United States measured the pH of soil samples taken from agricultural land across China in the 1980s and 2000s and found widespread acidification caused by nitrogen fertilisers.
On average, the pH of soil across the country had decreased by 0.5 in 20 years. In parts of Hunan province, in south China, the pH of the soil had dropped to between 3 and 4.
Most crops are suited to a neutral range between pH 6 and pH 8
Brown Mang Onwuka
Even slowing the amount of clearing of tropical forests could significantly cut the amount of heat-trapping carbon dioxide being released into the atmosphere, international experts say in a new study.
Deforestation in the tropics accounts for nearly 20 percent of carbon emissions caused by human activities, said Pep Canadell of the international scientific body Global Carbon Project and the CSIRO Division of Marine and Atmospheric Research.
“If by 2050 we slow deforestation by 50 percent from current levels…this would save the emission of 50 billion tonnes of carbon into the atmosphere,” he said.
The aim was also to stop deforestation when 50 percent of the world’s tropical forests remained. This would avoid the release of the equivalent of six years of global fossil fuel emissions, Canadell said.
The findings were published on Friday in the international journal Science from the first study of its kind by Canadell, of Australia’s government-backed Commonwealth Scientific and Industrial Research Organisation, and an international team of experts from the United States, Britain, Brazil and France.
Tropical deforestation released 1.5 billion tonnes of carbon each year into the atmosphere, the study showed.
“This will release an estimated 87 to 130 billion tonnes of carbon by 2100, which is greater than the amount of carbon that would be released by 13 years of global fossil fuel combustion,” Canadell said.
Forests soak up vast amounts of carbon dioxide, which is released again when the land is cleared and burned.
The study shows tropical forests will continue to accumulate carbon, although they could become less efficient sponges as global temperatures rise from climate change. This reverses previous belief, Canadell told Reuters.
He said the research showed the need to preserve tropical forests such as those in the Amazon and Indonesia.
Indonesia’s rainforests — especially those on Borneo island — are being stripped so rapidly because of illegal logging and palm oil plantations for bio-fuels, they could be wiped out altogether within the next 15 years, some environmentalists say.
Indonesia has a total forest area of more than 225 million acres (91 million hectares), or about 10 percent of the world’s remaining tropical forest, according to Rai nforestweb.org,
“If we invest in keeping climate change under control…it makes sense to invest in keeping that huge amount of carbon that’s stored in the tropics,” he told Reuters.
Brown Mang Onwuka