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测定土壤有机质,以前偶尔用铬酸氧化当量滴定法,为了满足分析上日益增长的需要,采用了有机质释稀放热法:在1立方厘米容量的一勺土样中加10毫升重铬酸钠氧化溶液,混合,摇匀后,置于85℃恒温箱中90分钟,冷却后用水稀释,用比色计测该颜色强度。试剂:重铬酸钠、硫酸。重铬酸钠氧化液——用1788克 Na_2—Cr_2O_4·2H_2O加7升水,制成3N重铬酸钠。把总量为3840毫升的浓硫酸分两次加入上述溶液。先将2009毫升H_2SO_4慢慢地加到重铬酸钠水的混合液中,充分搅拌;冷却后再
Determination of soil organic matter, and occasionally chromic acid oxidation equivalent titration, in order to meet the growing needs of the analysis, the use of organic matter release heat release method: a spoonful of soil capacity of 1 cm3 plus 10 ml sodium dichromate The solution was oxidized, mixed, shaken, placed in a thermostat at 85 ° C for 90 minutes, cooled and diluted with water. The color intensity was measured with a colorimeter. Reagents: Sodium dichromate, sulfuric acid. Sodium dichromate solution - Prepare 3N sodium dichromate using 1788 grams of Na_2-Cr_2O_4 · 2H_2O plus 7 liters of water. The total amount of 3840 ml of concentrated sulfuric acid added to the above solution in two. First 2009 ml H_2SO_4 slowly added to the mixture of sodium dichromate water, stir; after cooling