content is given by the weight difference of the sample before and after drying and is expressed in percentage by the weight of the dry soil. As this method requires only simple and cheap equipment (e.g. auger, balance, oven) and gives direct results, it is the most widely used one and also the one used to calibrate instruments in other methods. One major disadvantage is the effort required to obtain the necessary number of samples to yield significant moisture averages in soils with big variations in composition and texture or low absolute water content. The other is the fact that, the sampling disturbs the soil which makes this method unsuitable for continuous monitoring. 2.8.212 "Acetylene" method This technique to measure the water-content of a fine orb bsandy soil sample is based on the principle that water will react with calcium carbide to form acetylene gas and that the
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