Читать книгу Laboratory Methods for Soil Health Analysis, Volume 2 - Группа авторов - Страница 62

1 Weigh a stoppered, 50 mL Erlenmeyer flask containing 10 mL of 3 M HCl.

2 Transfer a 1 to 10 g air‐dried soil sample (containing 0.1–0.3 g of CaCO3 equivalent) to the container, a little at a time, to prevent excessive frothing.

3 After effervescence has subsided, replace the stopper loosely on the flask and swirl the flask occasionally for about 15 min.

4 At intervals of about 15 min, remove the stopper and swirl the flask for 10 to 20 s to displace any accumulated CO2 with air.

5 Replace the stopper and then weigh the flask and its contents to the nearest 0.1 mg.

6 Repeat the agitation and weighing procedure until the weight of the container does not change by more than 1 to 2 mg. The reaction is usually complete within 1 h.