While Lake Erhai has received much attention for its ecological preservation, the Lake basin has also suffered from high pollution, high deposits of nitrogen and phosphorus in the soil, and low agricultural yields. In the past, the protection efforts for the Erhai Lake were not coordinated with agricultural development, and farmers’ income suffered.
Village Science and Technology Backyard
Professor Zhang decided to explore a way to combine Erhai Lake preservation with high-quality agricultural development. Together with CAU, Yunnan Agricultural University and the government of Dali Bai Autonomous Prefecture, they jointly established the village’s first Science and Technology Backyard (STB) in February 2022. The goals of the Gusheng Village STBs are not only to maintain the purity of the Erhai Lake, but also to support local agricultural development.
Source of Pollution
Dali is encircled by mountain ranges on the south, west, and east. The Erhai Lake, covering an area of 252 square km, sits majestically in the center. The township, with beautiful natural scenery and the distinctive culture of the Bai ethnic group, is popular among tourists. However, the lake became so polluted in the 1980s that it emitted a putrid smell. Then, it saw three major blue-green algae outbreaks in 1996, 2003 and 2013.
Identifying the sources of the pollution was the primary problem faced by the teachers and students in the Gusheng Village STBs. Most of the water flowing into the Erhai Lake comes from Cangshan Mountain. In order to find out the source of pollution, the STB walked or rode electric trikes around the Cangshan Mountain and the Erhai Lake to observe the water system, set up monitoring points, and conduct sampling analysis.
Since April 2022, the Gusheng Village STBs have dispatched more than 1,000 personnel to conduct synchronous monitoring of water quantity and quality, collected more than 3,000 samples, and analyzed more than 20,000 water sample indicators, providing strong data support for tracing the source of surface pollution in the Erhai Lake.
Tang Bowen, a CAU graduate student who is mainly responsible for tracing and monitoring the source of pollution found that “pollution from farming did not account for 70 percent, as estimated by the government, but 30 percent to 50 percent. The rest of the water pollution comes from rural garbage dumps, house yards, vegetable fields, etc.,”
It was decided that the elimination of village pollution should start from the source and villagers were mobilized to participate in waste sorting and disposal. Almost every day 30 kg of kitchen waste is recovered and turn it into organic fertilizer through low-cost treatment methods.
Villagers observed that the lake water is getting clearer year by year, and sometimes Crucian Carp are seen jumping out of the lake. Local officials say that the water quality of the 27 main rivers entering the Erhai Lake has reached state standard, and the transparency of the lake has risen to the highest level in nearly 20 years.
The fertile plain of the basin extends from the foot of Cangshan Mountain to the bank of the Erhai Lake. In the fields of Gusheng Village, a sign is erected at each paddy field, which states the paddy variety, and the type and amount of fertilizer used. The green, high-value experimental plantation field of Professor Zhang’s team is located here.
The team started out with the intention of helping the local village to control the pollution of the Erhai Lake. However Jin Kemo, an associate professor of CAU in charge of the Gusheng Village STBs, and said that the focus is now on protecting the water of the Erhai Lake, as well as helping the village to find ways of growing crops that are both environmentally friendly and economically rewarding.
Gusheng Village has a population of over 1,400. In the past, garlic cultivation was the main source of income for the local farmers. At that time, the planting area of garlic in the Erhai Lake basin was nearly 13,333 hectares, with a yearly profit of over RMB 5,000 (US $702) per 0.067 hectare, far higher than that of general grain cultivation. However, garlic cultivation needs abundant water, fertilizer and pesticide, which undoubtedly creates pollution in the Erhai Lake. A large amount of pesticide and fertilizer remain in the farmland, and flow into the lake during the rainy season.
Professor Zhang noted that while the environment around the lake had improved, the villagers had not been benefitted economically, but “developing green and high-value agriculture can benefit farmers” said Zhang
The Gusheng Village STBs have set two major goals: One is to reduce nitrogen emissions from fertilizers by between 30 to 50 percent, and the other is to increase agricultural output value by more than RMB 10,000 (US $1,404) per mu.
In order to protect the Erhai Lake, in 2018, Dali Prefecture implemented a ban on the sale and use of nitrogen and phosphorus fertilizer and highly toxic residual pesticide. That brought the challenge of ensuring the nutrient supply of crops while reducing pollution.
Xu Jiuliang, a team member and associate professor of CAU, discovered through soil testing that the content of soil organic matter around in Gusheng Village is up to five percent, which indicates that the soil is very fertile, and does not need high fertilizer input to grow crops.
The team has introduced to the villagers eco-friendly fertilizer for rice and biodegradable mulch to cover the soil to retain moisture and nutrients. The application of these technologies has increased rice output by 30 percent, reduced the water contamination caused by nitrogen and phosphorus by 30 percent, and slashed fertilizer costs by 50 percent. “The average yield of rice per mu in the local area was around 680 kg. After using our fertilizer and technology, the yield per mu reached 808 kg, with a total increase of RMB 1,590 (US $223) per mu,” Xu Jiuliang said.
Nowadays, Gusheng Village uses efficient crop rotation models, with a yearly output value of nearly RMB 20,000 (US $2,809) per mu.
What pleased the team of scientists and students even more was that they were able to preserve the natural beauty of Dali.
Source of Inspiration Nationwide
Since 2009, Professor Zhang has led a team composed of teachers and graduate students from CAU to rural areas. They spend over 300 days a year in villages and eat, live, and work together with farmers, gaining first-hand experience of agricultural production and making the STBs popular among farmers.
In recent years, more and more graduate schools in China are sending their students to stay for long periods of time at the STBs in the front line of agricultural production in rural areas so that they can study and work out solutions to solve the practical problems of farmers based on their theoretical knowledge. Totally, CAU has established 139 STBs nationwide.
What makes the STB model feasible? What experiences are worth sharing? Zhang believes that the key is to help farmers to master and use technology in their daily farming work.
He said based on their experience, giving lectures to farmers has little effect. “Only by living and working together with farmers and gaining their trust can we help them to truly master the application of technology.”
“As agricultural technicians, we not only need to give farmers inspiration, but also encourage them to take actions. This requires us agricultural technicians to stay rooted in the countryside to work together with farmers,” Zhang said.
Oene Oenema, a Dutch scientist and Nobel Prize winner, has visited several STBs in China and was deeply impressed. “What STBs are trying to do is to truly make agriculture more sustainable. They can achieve higher yields while reducing environmental pollution and I think this is definitely a remarkable thing,” Oenema said.
Having been in place for 14 years, the STB model has also been used in other developing countries. In 2019, in order to share China’s experience, CAU created small classes for science and technology in China and Africa, and trained a number of high-quality agricultural talents for African countries. So far, the program has trained over 60 agricultural graduate students from 13 African countries, including Ethiopia, Tanzania, Mozambique, Malawi, and Burkina Faso. The Food and Agriculture Organisation of the United Nations has continuously promoted this cooperation model globally, calling it a typical case of empowering small farmers on the production front.
Source: China Today, 2023-08-02. http://www.chinatoday.com.cn/ctenglish/2018/et/202308/t20230802_800338438.html