The process of manufacturing artificial soils is divided into three steps:
Firstly, powder was made out of the 19 samples respectively by pounding, abrading and screening and became what I Call " the parent materials manufacturing soil'. This is real hard work and it took more than 2 months to finish with tools such as iron hammer, manpower abrader and 100 hole/ cm2 metal screens.
Secondly, the cow dung, the parent materials manufacturing soil (also called "inorganic raw powder”) and water were mixed homogeneously and the mixture was made to ferment at the temperature of 45-55℃ and in anaerobic conditions to enable the organic matter to be resolved into nutrients that could be absorbed by plants and became what I call “the compost manufacturing soil”. My way of doing it was to mix the powder of black mudstone (No.2 sample) and granite (No. 13 sample) with cow dung and water and then to pour the mixture into a big plastic barrel to expel the air in it by compressing. Use another upside-down plastic barrel of the same size to cover the plastic barrel and seal up the joint of the two barrels with sealing belt to isolate from air and to keep an anaerobic environment. The two plastic barrels were enclosed with an electrothermal pad and current was given to them to keep relative stable temperatures. Temperature testing indicated that the temperature at the center of the barrel could reach 55℃ at the maximum and the temperature at the sides of the barrel was 10℃ lower. This process took 100 days. The gas produced during fermentation was sampled twice for ignition testing. Blue flame was observed in the first test, which indicated that a lot of methane existed while no flame was observed in the second test because of no combustible gas in the barrel, which indicated the decompounding peak of organic matter had been over.
Thirdly, the different parent materials manufacturing soil and the compost manufacturing soil were mixed homogeneously at proper ratio to form artificial soils. Among the artificial soils, the one with one parent material manufacturing soil was called one-element artificial soil and the one with three parent materials for manufacturing soil was called three-element artificial soil and so on and so forth. In the test, 21 samples of artificial soil were formulated, including 19 one-element artificial soils and one three-element artificial soil and one eleven-element artificial soil.