Paddy field crisis in Southwest China: water conversion to drought increases and destroys disaster resistance and health

The paddy fields that can be seen everywhere in southwest China are suffering from crisis, with the increase of "water to drought", the increase of abandonment and the continuous decrease of the number. This not only directly affects the agricultural production, but more importantly, the rice field is still a huge water conservation land in the southwest, and its destruction brings great hidden dangers to the agricultural disaster resistance and ecological environment.

Acreage decreased

Southwest China (mainly including Yunnan, Guizhou, Sichuan and Chongqing) is one of the main rice producing areas in China. According to a survey on the utilization of paddy fields in southwest China conducted by the Science and Technology think Tank of Chongqing Municipal Association of Science and Technology in 2014, the population of southwest China accounts for 14% of the country's total population, planting about 67 million mu of rice every year, with an annual output of more than 30 million tons, accounting for about 16% of the country's total output. it is the main source of food rations in southwest China.

Zhang Hongsong, head of the project team and president of the Chongqing Agricultural Association, said: "according to preliminary estimates, the existing paddy field storage capacity in southwest China is about 10 billion cubic meters, which is a huge reservoir and flood detention reservoir, which can not only conserve water sources and reduce soil erosion, but also alleviate drought in early spring and effectively ensure the safety of drinking water for people and livestock and grain production in the following year."

In recent years, the problems such as the decline of rice planting area, drought and seasonal abandonment in southwest China are becoming more and more serious. "in many places, the key points of urbanization construction are laid out in the shallow hilly and flat dam areas covered with high-quality paddy fields, and the phenomenon of 'occupying paddy fields and replenishing sloping land' is common in the balance of cultivated land occupation and compensation. Some urban capital projects in rural areas have changed the rice-growing areas with good production conditions and supporting facilities to cash crops." Zhang Hongsong said.

According to statistics, from 2000 to 2012, the average paddy field area in southwest China was 67.52 million mu, which was 5.06 million mu less than the average area in the 1980s, while the national paddy area remained basically stable in the same period. Correspondingly, from 2003 to 2012, the country's total grain output increased by 36.9%, of which rice increased by 27.1%, while the total rice output of the four provinces and cities in southwest China increased by only 0.55%.

Important natural wetlands

The role of rice fields is not just to provide agricultural products. "Winter paddy field is an effective rice farming system in southwest hilly and mountainous areas where there is a lack of water conservancy projects and unmatched irrigation conditions. In the spring ploughing season, in addition to protecting Honda to plant seedlings, there is excess water for other agricultural land, which is a low-cost drought-resistant 'reservoir' and natural ecological wetland. " Xiong Hong, a post scientist in the rice industry system of the Ministry of Agriculture.

The so-called "winter paddy field" means that some conditional rice fields store autumn rain for the winter after rice harvest, which has been used by farmers in southwest China. However, in recent years, due to the lack of labor and other factors, some places do not plough or store water in autumn after harvest, which affects the timely planting of rice, and finally chooses to "use water to change drought", resulting in a decrease in the area of paddy field in winter year by year.

Take Chongqing as an example, in 1996, the area of paddy fields in winter was 5.43 million mu, accounting for about 45% of the area of paddy fields in the city. At present, the area of paddy fields in winter is less than 3 million mu, and nearly half of them have become dry plank fields. Since 2006, serious spring droughts have occurred in many areas in southwest China successively. In addition to abnormal climate, arrears of irrigation and water conservancy construction and other reasons, winter paddy fields originally used as "protection reservoirs" have not been well maintained and renovated, thus weakening the ability of agricultural drought resistance and destroying the ecological balance of agriculture.

In addition, in the view of experts, rice fields not only provide the most important local food rations, maintain the ecology, but also have the function of cultural heritage. For example, rice terraces are the great creation and typical representative of traditional farming culture in southwest China. Terraces are dotted among mountains and hills, and rich rice cultural connotations have been accumulated in the long history of agricultural development.

Zhu Youyong, academician of the Chinese Academy of Engineering and former president of Yunnan Agricultural University, said: taking the Honghe Hani terraces in Yunnan as an example, the culture with national characteristics formed by the combination of natural landscape, farming activities, and folk customs has attracted a large number of Chinese and foreign tourists and is of positive significance in popularizing agricultural knowledge, guiding people to protect arable land and protecting folk culture.

More attention is urgently needed.

Although paddy fields are of great significance to the southwest, especially in terms of ecological environment, local farmers have little enthusiasm for the protection of paddy fields. Because on the whole, the production condition of rice field in southwest hilly area is poor, and the planting benefit is not ideal.

Zhang Hongsong said that the southwest region has a large population, agricultural land resources are relatively scarce, and the planting scale of rice fields per household is small. Take Chongqing as an example, at the end of 2013, the average arable land of farmers in Chongqing was 5.4 mu, of which paddy field was less than 2.3 mu, 40% lower than the national average. In addition, the household contract is generally contracted according to quality, that is, "good or bad, far and near", which leads to more detailed land fragments, hinders the large-scale operation of land, and is not conducive to the protection of rice field resources.

According to the survey, nearly 70% of the paddy fields in Chongqing have a slope greater than 6 °, of which more than 20% are more than 15 °. "to carry out the construction and transformation of high-standard farmland in hilly areas, it is necessary to adjust a large number of field types, move earthwork, and match roads and canals, no matter the project quantity or cost is several times higher than that in the plain areas. however, the national investment standard of our country often takes the plain as a reference, and the infrastructure transformation is extremely difficult." Professor Xie Deshi, dean of the School of Resources and Environment of Southwest University, said.

For a long time, people are used to regarding rice output as the only function of rice field, while ignoring its important ecological function, so people do not pay enough attention to the reduction of rice field. Experts suggest that pilot projects of ecological compensation for rice fields should be carried out in important water conservation areas, areas with serious soil erosion, and important flood storage and detention areas in the upper reaches of the Yangtze River, so as to encourage farmers to protect rice field resources, so as to better realize their agricultural, ecological and other benefits. (reporter Li Song) Source: half-monthly talk