|用0.50 mol/L碳酸氢钠溶液浸提中性和石灰性土壤中的有效磷。碳酸氢钠可以抑制溶液中Ca2+的活度，使某些活性较大的磷酸钙盐被浸提出来，同时也可使活性磷酸铁、铝盐水解而被浸出。浸提液与钼锑抗显色剂反应生成磷钼蓝，在波长880 nm处测量吸光度。当取样量为2.50 g，使用50 ml碳酸氢钠溶液浸提，使用1cm比色皿时，检出限为0.4 mg/kg，测定下限为1.6 mg/kg，满足了土壤有效磷的监测要求。
|关键词: 土壤 有效磷 碳酸氢钠浸提 分光光度法
|Determination of Available Phosphorus in Soil by Sodium Bicarbonate Extraction Mo –Sb Anti-spectrophotometry Method
|The available phosphorus was extracted by 0.50 mol/L sodium bicarbonate solutionin neutral and calcareous soil. Sodium bicarbonate solution can inhibit the activity of Ca2 +, so that the calcium phosphate of large activity were extracted; meanwhile active iron phosphate and aluminum salt was leached by hydrolysis. Molybdenum Blue reaction occurred by mixing elution and Mo-Sb anti-chromogenic reagent and the absorbance was measured at a wavelength of 880nm. In this study, the method of measuring concentrations of available phosphorus in soil was developed. The sample volume was 2.50 g and sodium bicarbonate solution was 50 ml. The detection limit of this method was 0.4 mg/kg and lower limit was 1.6 mg / kg when 1 cm cuvette was used.
|Key words: soil available phosphorus sodium bicarbonate extraction spectrophotometry