Ai dịch đoạn này cho em với , em dịch mãi mà cũng không hay đượcThe importance of organic carbon estimation lies inthe fact that it gives an indication of the organic matter content of the soil which is an important index of soil fertility. The organic carbon content of soil, is reported directly as percentage of C or calculated as organic matter by multiplication with a factor of 1.724 assuming that soil organic matter contains on an average 58 percent carbon, so that 100/58 = 1.724. There... Ai dịch đoạn này cho em với , em dịch mãi mà cũng không hay đượcThe importance of organic carbon estimation lies inthe fact that it gives an indication of the organic matter content of the soil which is an important index of soil fertility. The organic carbon content of soil, is reported directly as percentage of C or calculated as organic matter by multiplication with a factor of 1.724 assuming that soil organic matter contains on an average 58 percent carbon, so that 100/58 = 1.724. There is also a close relationship between organic carbon and nitrogen content of the soil (C : N ratio). For organic carbon determination dry combustion and wet digestion methods are used. The former is useful for very accurate purposes since absolute values are obtained, while for routine work Walkley-Black rapid titration method (wet combustion) is extremely useful. Soil organic carbon is oxidized to C02 in presence of an excess of oxidizing agent such as a mixture of potassium dichromate and sulphuric acid. It is actually the chromic acid formed by the action of potassium dichromate and sulphuric acid which oxidizes the carbon. The excess of dichromate is determined by blank titration with ferrous ammonium sulphate (redox titration). The Walkley Black procedure uses the heat of dilution of sulphuric acid to provide the temperature required. However, this does not enable the dichromate to oxidize all the organically bound carbon. An empirical recovery factor of 0.77 was used by the original authors
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05/11/15 08:25:59Dịch đúng nghĩa kỹ thuật là sao ạthe role of soil microbial biomass must be taken into consideration in any attempt to assess nutrient and energy transfer within soil system.
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