Cyanobacteria are now being used in China to shore up the verges of roads and railways in northern China as well as the margins of oases and farmland. A team plans to seed 133 square kilometer of desert over the next five years. The bacteria creates 0.5 to 1.0 centimeter thick biocrust over the desert which helps topsoil to reform and prevents top soil erosion.
People have been trying to use bacteria in this way since the 1980s, says Matthew Bowker, a soil ecologist at Northern Arizona University in Flagstaff. His group is working on a similar method, but hasn’t yet used it on a large scale. China is willing to put in the money to scale the process.
Planting hardy grasses helps keep sand in place, but the wind can still whip away particles between the grasses. So Chunxiang Hu of the Chinese Academy of Sciences’s Institute of Hydrobiology in Wuhan has developed an alternative approach. She coats planted dunes with a mixture of photosynthesising cyanobacteria that can thrive in the semi-arid environment.
China has run a trial for eight years and is scaling it up now
Grown in nearby ponds, the cyanobacteria are trucked into the desert every few days and sprayed over the dunes, where they form sticky filaments that hold soil particles in place and prevent them from being blown away. Cyanobacteria get their energy from sunlight via photosynthesis, and as part of the chemical reactions involved, they absorb carbon from the atmosphere and provide the organic matter the soil needs to be productive.
Hu’s long-running trial shows that after eight years, dunes treated with cyanobacteria developed a biological crust nearly 1 centimetre thick when on the shady side of dunes. On the sunny side, the crust was about half as thick. The topsoil improved where the crust developed, spurring plant growth
Desertification has been recognized as a global environmental problem, and one region experiencing ongoing desertification is the eastern edge of Qubqi Desert (Inner Mongolia). To investigate the facilitating effects of cyanobacterial inoculation technology on the desertification control along this steppe-desert transition region, artificial cyanobacterial crusts were constructed with two filamentous cyanobacteria 3 and 8 years ago combined with Salix planting. The results showed that no crusts formed after 3 years of fixation only with Salix planting, whereas after cyanobacterial inoculation, the crusts formed quickly and gradually succeed to moss crusts. During that course, topsoil environments were gradually improved, providing the necessary material basis for the regeneration of vascular plants. In this investigation, total 27 species of vascular plants had regenerated in the experimental region, mainly belonging to Asteraceae, Poaceae, Chenopodiaceae and Leguminosae. Using space time substitution, the dominant species along with the application of cyanobacterial inoculation technology succeeded from Agriophyllum squarrosum ultimately to Leymus chinensis. In addition, it was found that the shady side of the dunes is more conducive to crust development and succession of vegetation communities. Conclusively, our results indicate artificial cyanobacterial inoculation technology is an effective and desirable path for desertification control.
Other means of fighting the deserts
Hydrophobic sand can placed into sheets and buried to produce a shallow artificial water table. This keeps the water that does rain up near the roots of plants. A factory making it at 3000 tons per day would have enough for about 80 square kilometers per year. However, this has the large cost and effort of moving a lot of sand to bury the hydrophobic sheets. The bacteria method is just spraying what is grown in water ponds.
China has a big desertification risk
Of the 400 million hectares of grassland that cover more than 40% of China, 90% has suffered some degree of deterioration
Desertification is estimated to cause direct economic losses of 54 billion yuan ($8.44 billion) annually, Tang Yuan, a researcher from a State Council think tank, said in a previous interview with Xinhua.
China is creating massive canals and other hydro projecs to take seawater across the country to make new seas
Evaporation from seawater lakes filled from the east coast will produce rain in western deserts.
Huo Youguang, a professor at Xi’an Jiaotong University’s Center for Environment and Modern Agriculture Engineering and one of the authors of the plan to move seawater west, said it would advance the cause of Xinjiang ecology, particularly in the development of the coal chemical industry.
According to Huo, water taken from the Bohai Sea near Tianjin would be sent through sets of pipes to an elevation of 1,280 meters above sea level. One ton of water raised 200 meters requires 1 kWh of energy, or 6.4 kWh for the full 1,280 meters. Then, using anti-seepage canals and small-scale step-up works (such as reservoir ponds to increase elevation) to extend the natural flow distance, the water will reach the Shulei River near Yumen, Gansu, by way of Huangqihai Lake. Then, using the westward flow of the Shulei River, it will flow naturally into the eastern border of the Tarim Basin at Lop Nur.
“The biggest questions in the Moving Seawater West project are whether the water can be used, and how to resolve the issue of cost,” said Yang Kailin of the China Institute of Water Conservancy and Hydro-Electric Power. He said semi-permeable membranes would be used to remove the salt, a method that has the advantage of conserving energy. Producing the same quantity of water by distillation requires 40 times the power….Yang said that there is currently no “bottleneck” for desalinating water in China. The project can employ reinforced plastic piping that is impervious to corrosion by seawater. Using 8-meter pipe, the cost for sending a ton of water to Xinjiang would be around 8 RMB.
The first stage of the project is expected to require 62.8 billion RMB (56.7 billion for construction), and one expert predicted that it could be realized within six years.
This massive engineering project will require forty years to complete, at which point it will transform the ecology of China, vastly improving the living conditions for the Chinese people and bringing prosperity to their descendants. Reportedly, comprehensive talks on the plan are now in progress.
China is planting billions of trees to try to stop the spread of desert. But 85% of the newly planted forests may not survive. About 20,000 square kilometers were planted each year (about 8000 square miles about the area of Massachusetts).
China is claiming some success. After prolonged efforts, desertification in China has been initially reversed, with trees and grass springing up where deserts used to be.
“In the 1990s, the desertification area would increase nearly 3,500 square km every year. But after ten years of work, the situation has been overturned. About 1,500 square km of desert can be turned into greenery every year,” said Luo Bin, deputy director of the National Bureau to Combat Desertification under the State Forestry Administration, at the Kubuqi International Desert Forum, which is being held in the city of Ordos in north China’s Inner Monoglia Autonomous Region.
According to statistics released by the State Forestry Administration, China has 2.6 million square km of desert, accounting for 27 percent of the country’s total land area. The desert areas are scattered among 12 provincial-level regions in north China.
In recent years, the central government has spent vast amounts of money to prevent desertification. In some areas, vegetation coverage has expanded by 20 percent over the last decade.
“In its next step, China plans to have about 200,000 square km of desertified land, or half of the country’s desert area that can be reversed, harnessed by 2020 and improve living standards for people living in the desert,” Luo added.
However, the biggest challenge will be to prevent sandstorms from hitting the cities of Beijing and Tianjin, Luo said, adding that 56 billion yuan (9.1 billion U.S. dollars) has already been spent on this endeavor in the past ten years and 84.4 billion yuan more will be spent in coming ten years