How to Make Fire-Baked Soil and Its Key Technical Points

In the article "Let Each Enjoy His Own Hobby at the Orchid Expo" published in the fifth issue of "Orchids" in 2002, Professor Liu Qingyong at the end introduced the remarkable story of Mr. He Weibin and Mr. Liang Yaofen of Shawan, Panyu, propagatingCymbidium ensifoliumXiaotaohong. They "used only ordinary sawdust and broken rice husks plus fire-baked soil forcultivation, and used agricultural compound fertilizer granules soaked, dissolved and diluted in water as fertilizer. Each year each plant propagated 3-4 shoots, and after thirteen years without selling any, seven plants multiplied to more than 400,000 plants, becoming a great orchid kingdom." Among these, fire-baked soil was the key. How is fire-baked soil made? Some orchid growers think fire-baked soil simply means soil that has been burned with fire. As for how it is burned, it certainly does not mean putting the soil into a stove to burn. Fire-baked soil is called "shangpishuo" among the farmers of Zhijin, and farmers mostly use it as base fertilizer for growing vegetables or grain crops. Especially on remote mountain fields, where transporting farmyard manure is difficult and transportation is inconvenient, they use local materials and often use fire-baked soil as base fertilizer for growing wheat. At autumn harvest, because the mountain paths are rugged and far from home, they thresh the wheat on the mountain and carry it home on their backs, leaving the wheat straw behind. On a sunny day, farmers on the mountain dig up the topsoil together with weeds, spread it out piece by piece and dry it in the sun. If it does not rain, it dries in three to five days. The sun-dried topsoil with weeds is gathered together; first dry grass and dry branches are laid on the bottom layer, then the sun-dried topsoil is piled on top, and fire is lit from the bottom layer. After it catches fire, soil is added while it burns, until all is burned. The parts around the fire pile that were not burned are then piled on and burned too. After burning, the soil pile is spread out to cool down. After it has thoroughly cooled, it is piled up again and left to be rained on several times. Because fire-baked soil is generally alkaline, after being piled on the mountain and rained on, it gradually becomes weakly acidic and can then be used as growing medium for plantingorchids. This kind of fire-baked soil is actually "fire-smoked soil." Therefore, using it asorchidgrowing medium is very good. First, through high-temperature burning and smoking, it both has fertilizing effect and sterilizes, and is very hygienic; second, the weeds and branches burned together with the topsoil become ash mixed into the soil and also contain phosphorus and potassium fertilizer, while the smoke-treated soil also contains nitrogen fertilizer; third, fire-baked soil has no stickiness and has good looseness and air permeability. Therefore, adding sawdust and rice husk to fire-baked soil further strengthens its air permeability. As it happened, when the author was going up the mountain to collect orchids in 1998, he accidentally discovered that farmers used fire-baked soil as base fertilizer for growing vegetables; especially the Chinese cabbage grown where fire-baked soil had been piled grew particularly luxuriantly. Inspired by this accidental discovery, he thought of using fire-baked soil to groworchids. In 1999, the author used only fire-baked soil without adding any root material, and deliberately planted two pots ofCymbidium goeringiias a comparative experiment. One year later, he found that these two pots ofCymbidium goeringiiwere particularly good. By the way, he pulled out one pot to observe the orchid roots; the roots had grown very well, both numerous and long and white, which was most pleasing. From then on, he used local materials and mostly used fire-baked soil to plant orchids. According to the author's observations over several years, pure fire-baked soil can also be used to grow orchids. However, after a long time, its air permeability becomes poor. Therefore, sawdust or rice husk must be added. If at the same time a small amount of coarse humus soil is also added, the effect is even better. I do not know whether the making of fire-baked soil introduced by Mr. Liu Qingyong is like this. The author only wishes to offer his own humble opinion to invite better ideas. An Qichang, Guizhou Contact address: No. 102, supplementary No. 36, Shuangyan Road, Chengguan Town, Zhijin County, Guizhou Province Postal code: 552100 Telephone: 0857-7625573