The invention relates to a method for the
combined test of
total nitrogen and total
phosphor phosphorus in soil, which comprises the following steps: (1) synchronous
digestion treatment of soil: weighing a dried and screen soil sample, placing the sample into a
digestion tube, adding an accelerator, adding solution of concentrated
sulfuric acid and placing the
digestion tube in at high-temperatureenvironment for digestion; (2) preparation of soil liquid to be tested: after the digestion liquid obtained after digestion is cool, fixing the volume of the digestion liquid by adding
distilled water, using the digestion liquid to test the
total nitrogen content of the soil, adjusting the pH value of soil
total nitrogen liquid to be tested by using alkaline liquid and using the resulting liquidto test the total
phosphor content of the soil; and (3) test of the total
nitrogen content and total
phosphor content of soil: automatically testing the total
nitrogen content and total phosphor content of soil by using a constant flow injection analyzer. The method has the advantages of: 1, avoiding repeated soil sample weighing and soil digestion and simplifying experimental operation process; 2, avoiding damages of
selenium powder to human bodies by using
potassium sulfate and
copper sulfate in place of the accelerator for soil
digestion treatment; and 3, improving
accuracy and precision bytesting total
nitrogen content and total phosphor content of soil by using constant flow injection analyzer.