More paddy fields in southwest China converted from water to dry land, undermining disaster resilience and the ecological environment

    Paddy fields seen everywhere in southwest China are facing a crisis: more and more are being converted from water to dry land, more are being left abandoned, and their number keeps shrinking. This not only directly affects agricultural production but, more importantly, paddy fields in the southwest also serve as a huge water conservation area, and their destruction poses no small hidden risk to agriculture's disaster resilience and the ecological environment.

    Planting area declining

    The southwest region (mainly comprising Yunnan, Guizhou, Sichuan and Chongqing) is one of China's main rice-producing areas. According to a 2014 survey of paddy field use in the southwest by a research project of the Chongqing Association for Science and Technology's science and technology think tank, the southwest accounts for 14% of the country's total population, has long grown rice on about 67 million mu, and produces more than 30 million tonnes a year, about 16% of the national total, making it the main source of staple grain in the southwest.

    Zhang Hongsong, head of the project research group and president of the Chongqing Agricultural Society, said: “According to preliminary estimates, the existing paddy fields in the southwest hold about 10 billion cubic metres of water, making them a huge reservoir and flood-detention basin. They can not only conserve water sources and reduce soil erosion, but winter water storage can also ease early-spring drought, effectively safeguarding the safety of drinking water for people and livestock and the following year's grain production.”

    In recent years, problems such as the decline in rice planting area, conversion to dry land and seasonal abandonment have become increasingly serious in the southwest. “Many places have placed the focus of urbanisation construction in shallow-hill and flat-basin zones densely covered with high-quality paddy fields, and in the balancing of cultivated land occupied and replenished there is a widespread phenomenon of ‘occupying paddy fields and replenishing with sloping land’; some urban capital-to-the-countryside projects have switched rice-growing areas with good production conditions and supporting facilities to cash crops.” Zhang Hongsong said.

    According to statistics, from 2000 to 2012 the paddy field area in the southwest averaged 67.52 million mu a year, a decrease of 5.06 million mu from the average area in the 1980s, while the national paddy field area remained basically stable over the same period. Correspondingly, from 2003 to 2012, national total grain output grew by 36.9%, of which rice increased by 27.1%, while the total rice output of the four southwest provinces and Chongqing grew by only 0.55%.

    An important natural wetland

    The role of paddy fields is not limited to providing agricultural products. “Winter water paddy fields are an effective rice-field farming system in the hilly and mountainous areas of the southwest, where water conservancy works are lacking and irrigation conditions are not fully in place. During spring ploughing, besides retaining water for planting rice in the field itself, there is surplus water for other farmland, making it a low-cost drought-resistant ‘reservoir’ and a natural ecological wetland.” said Xiong Hong, a scientist at the rice industry system post of the Ministry of Agriculture.

    The so-called “winter water paddy field” refers to paddy fields with suitable conditions that, after the rice harvest, store autumn rain through the winter, a practice long adopted by farmers in the southwest. In recent years, however, owing to factors such as a shortage of labour, in some places the fields are not ploughed or filled with water after the autumn rice harvest, which affects timely rice transplanting, and ultimately leads to the choice of “converting water fields to dry land”, causing the area of winter water paddy fields to shrink year by year.

⟦NL>     Taking Chongqing as an example, in 1996 the area of winter water paddy fields was 5.43 million mu, about 45% of the city's paddy field area; at present the area of winter water paddy fields is less than 3 million mu, and nearly half have become dry flat fields. Since 2006, many areas in the southwest have suffered severe spring droughts in succession; besides abnormal climate and arrears in farmland water conservancy construction, the fact that winter water paddy fields, originally serving as “water-holding reservoirs”, have not been well maintained and repaired, weakening agriculture's drought resistance and disrupting the agricultural ecological balance, is also an important reason.

    In addition, in the view of experts, paddy fields not only provide the most important local staple grain and maintain the ecology, but also have a cultural heritage function. For example, rice terraces are a great creation and typical representative of the traditional farming culture of southwest China; the terraces are scattered across mountains and hills, and over the long history of agricultural development they have accumulated rich rice-farming cultural connotations.

    Zhu Youyong, an academician of the Chinese Academy of Engineering and former president of Yunnan Agricultural University, said that taking the Honghe Hani Terraces in Yunnan as an example, the ethnic-featured culture formed by the combination of its natural landscape, farming activities and folk customs has attracted many Chinese and foreign tourists, and has positive significance for popularising agricultural knowledge and guiding people to protect cultivated land and folk culture.

    Urgently in need of more attention

    Although paddy fields are of great significance to the southwest, especially in terms of the ecological environment, local farmers have little enthusiasm for protecting them. This is because, overall, rice-field production conditions in the hilly areas of the southwest are relatively poor and planting returns are not ideal.

    Zhang Hongsong said the southwest has a large population and relatively scarce farmland resources, and the average household rice-field planting scale is small. Taking Chongqing as an example, at the end of 2013 the average cultivated land area per farmer household in Chongqing was 5.4 mu, of which paddy fields were less than 2.3 mu, 40% lower than the national average. In addition, under the household contract responsibility system, land was generally contracted according to quality, that is, “good and bad matched, near and far matched”, which made the land even more fragmented, hindered large-scale land operation and was unfavourable to the protection of paddy field resources.

    According to the survey, nearly 70% of paddy fields in Chongqing have a slope greater than 6°, of which more than 20% are greater than 15°. “Carrying out high-standard farmland construction and improvement in hilly areas requires extensive adjustment of field shapes, movement of earth, and supporting roads and canal systems; both the amount of work and the cost are several times those in plain areas, while China's national investment standards often take plains as the reference, making infrastructure improvement extremely difficult.” said Professor Xie Deti, dean of the College of Resources and Environment at Southwest University.

    For a long time, people have been accustomed to seeing rice output as the only function of paddy fields, while ignoring the important ecological functions behind them, and therefore have paid insufficient attention to the reduction of paddy fields. Experts suggest that in important water conservation areas in the upper reaches of the Yangtze River, areas with severe soil erosion, and important flood storage and detention areas, pilot ecological compensation for paddy fields should be carried out to encourage farmers to protect paddy field resources, so as to better realise their agricultural, ecological and other benefits. (Reporter Li Song) Source: Ban Yue Tan