Premium
Determination of the Partial Pressure of Ammonia in Soil Air
Author(s) -
Blanchar R. W.
Publication year - 1967
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1967.03615995003100060024x
Subject(s) - bottle , ammonia , ammonium hydroxide , chemistry , ammonium , polyethylene , nitrogen , volume (thermodynamics) , ammonia gas , partial pressure , analytical chemistry (journal) , zoology , chromatography , materials science , oxygen , inorganic chemistry , organic chemistry , physics , quantum mechanics , composite material , biology
A method for determining partial pressures of NH 3 from 0.01 to 0.50 mm Hg in soil air was studied. Soil samples which had been treated with various amounts of ammonium hydroxide were placed in 1‐liter polyethylene bottles and allowed to equilibrate. A known volume of air from the bottle was removed by partially compressing the bottle with a press. The air was bubbled through 0.1 N HCl and the ammonium content of the acid determined by the Nessler reaction. The partial pressure of NH 3 (P NH3 ) was calculated from the ideal gas law equation. The method gives a reliable estimate of the partial pressure of NH 3 in soil air. It was shown that the P NH3 of a sample placed in the polyethylene bottle could be determined after a 1‐hour equilibration period. Samples which were sealed in the polyethylene bottles for 48 hours had lower P NH3 and higher P CO2 values than samples placed in the bottles for only 1 hour. Reduced P NH values in bottles which had been sealed for 1 day or more were attributed to pH reduction due to CO 2 accumulation. Germination of corn seeds ( Zea mays L.) was damaged when the initial P NH2 value was 0.156 and final values were between 0.077 and 0.104 mm Hg. The germination of corn seeds was not reduced when initial P NH3 values were 0.091 and final values were 0.067 and 0.048 mm Hg.