Straw checkerboard

The straw checkerboard technique is used for fixing sand dunes to fight desertification. Straw of wheat, rice and reeds are placed in the shape of a checkerboard and half buried. It has a windbreak effect and contributes to soil formation through the increase of organic matter of the surface soil.^[1]

To understand the history of the straw checkerboard technique, it is good to provide some context as to how it came to be considered as a way to combat desertification. The history of desertification begins in 1847 when scholars further examined the dispersal of atmospheric dust ^[2]. However, it was not until the 1920s and 1930s that wind erosion and desertification received further investigation through isolated incidents occurring in the United States at the time^[2]. Then in 1939, wind erosion and other related weather events that lead to desertification were further studied and experimented by Chepil and Milne^[2]. As a result of their findings from their experiments, they were able to formulate a formula for wind erosion. It was in this context that the straw checkerboard technique was conceived at the Shapotou Desert Research Station of the Chinese Academy of Sciences in 1955^[3] to protect the Baotou–Lanzhou railway crossing the Tengger Desert,^[4] where planting of sand-fixing plants without irrigation was carried out as early as 1956.^[5] It was earlier used in the Soviet Union, which used the technique during the construction of a railway in the Karakum Desert in Central Asia.^[6] It is widely used in China.^[1]

A 2004 study concluded that it is "a very effective technique, with wide application for sand dune fixation both in China and around the world."^[1] while a 2013 study described it as "the most representative antidesertification measure."^[7] Straw checkerboards and planting shrubs are successful methods for mobile sand dune stabilization and desertified grassland restoration in semiarid regions.^[8] One example of such shrub is Carex Brunnescens, which a shrub that has shown effects in combating desertification and assisting in the process along with the straw checkerboard technique^[9]. One study found that the straw checkerboard technique, along with planting shrubs, was able to reduce the toxic runoff from zinc and lead mining^[10]. Another study found that straw checkerboard barriers are more suitable for sand fixation in weak wind areas, while rocky checkerboard barriers are more suitable in strong wind areas.^[11] Furthermore, another study exhibited success with the technique in alpine sandy lands^[12]. Traditionally done by hand, the straw checkerboard technique has also started to become an automated process^[13]. Such work on automating the straw checkerboard technique began with the 863 Program project at the Northeast Forestry University where the process was first developed conceptionally^[13]. Further on, this process escaped from conception and began being mechanized and further developed over the years as more studies and developments were done to refine the machinery developed for the straw checkerboard technique^[13]. From these developments an automated straw checkerboard laying machine has been developed that is 53 times faster than manual methods.^[14] However, challenges still remain in the development of straw checkerboard machinery such as their immense size and difficulties in dealing with harsh terrain^[15].

It has seen limited use in Iran,^[16] Ghana, Egypt, Mongolia.^[17]