|MadSci Network: Earth Sciences|
Hi, This is a good question. In a scientific lab environment, it is easy to use some specific instruments, such as specific chromatography for testing ion concentrations, and PH meter for checking acidity. But if you do not need very precise data, general chemical knowledge is enough. My proposal only requires PH test paper (which is always short, slip of paper), beakers, several chemicals, water, fire and your chemical knowledge. For acidity: Put your soil sample into small volume of water, stir and leave for a while, you should get a small amount of solution cover the soil. Now wet your PH test paper in the solution, compare to the instruction of the test paper, you can know the approximate PH of your soil sample. For nutrient levels: Generally speaking, the most important nutrients in soil including organic components and inorganic components [nitrogen (NO3- or NH4+), potassium (K+ ), phosphorus (HPO42+ or H2PO4+), sulfur (SO42-) and some elements like Fe and Cu}, so you will know nutrient level of your sample after you know the concentration these components. For organic components, you can heat your sample until no visible fumes, compare the weight before/after heating, you can know the amount of organic components. About the inorganic components, the first step is to get clean solution from your sample. You need to stir your sample in a larger amount of water, get through the filter, and maybe your need to heat your sample to get crystals of salt. After get solution of your sample which contains all the salts, you can do a series of chemical experiment to figure out the components and their concentration. For example, NH4+ is not very stable and may form NH3 after heating. So if you feel stimulus smell, your sample may contain NH4+; Ca++ can form precipitation with SO42-, so if you add Ca++ and see white precipitation, it's possible that your sample contains SO42-. Reference: http://www.eosc.osshe.edu/peers/lessons/peerlessons.html
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