Chinese soil experts warn of massive threat to food security

Ding Jie SciDev.Net Reuters AlertNet 16 Aug 10;

[BEIJING] If China's current rate of soil loss continues, a layer the size of Puerto Rico will be washed away in the next 50 years - resulting in a 40 per cent decrease in food production, according to a study led by the country's Ministry of Water Resources, and science and engineering academies.

The two-year Soil Erosion and Ecological Safety expedition took place from 2005 to 2007 and was followed by three years of data analysis. Around 200 scientists surveyed 27 provinces in China, focusing on seven regions with different soil types, such as north-eastern black soil, northern Rocky Mountain soil, red soil and Karst.

Scientists found that the total area of soil erosion has reached nearly 17 per cent of total land cover. According to the study, many parts of the black soil in northeastern China - the country's breadbasket - have disappeared already, a trend that, if it continues, could put at risk food security for one million people.

"The most serious soil erosion exists in the slope land, especially in farmland," Lu Zongfan, a researcher at China's Institute of Soil and Water Conservation and consultant for the expedition, told SciDev.Net.

Liu Xingtu, a geographer at the Chinese Academy of Engineering, said that soil erosion can degrade soil surface, deteriorate soil structure and reduce soil fertility. Scientists estimate that more than 30 per cent of counties are currently experiencing land erosion.

According to the Ministry of Land and Resources, China has 239,000 hectares of slope land in China. This accounts for almost 20 per cent of arable land and 13.3 per cent of soil erosion areas. And at the same time, the quantity of soil erosion from slope land makes up a third of the total soil loss.

"During the heavy rain, the outflow of soil reaches up to one centimetre, resulting in soil fertility decline [as rain washes away fertile soil on the surface layer, exposing poor soil below] inevitably decreasing food production," said Lu.

The report suggests some solutions for protecting China from further land erosion.

"The key to solving these problems is to transfer slope lands into terraces, to build terraced fields and small water storage projects," said Sun Honglie, a geologist at the Chinese Academy of Sciences and a member of the expedition.

The results of the survey were presented at a press briefing in Beijing last month (19 July).