A rapid steam distillation method of assessing potentially available organic nitrogen in soil

Abstract

A rapid steam distillation of assessing potentially available organic nitrogen in soil is described. It involves determination of the ammonia‐N produced by steam distillation of the soil sample with pH 11.2 phosphate‐borate buffer solution for 8 min. The method is simple and precise, and its results are not significantly affected by air‐drying or air‐dry storage of the soil sample before analysis. It is well suited for use in soil testing laboratories because it does not require extraction, filtration or transfer steps. Studies using 33 Brazilian soils showed that the results obtained by this method were highly correlated with those obtained by aerobic and anaerobic incubation methods of assessing potentially available organic nitrogen in soil.

Key words:

• Ammonia
• phosphate‐borate buffer
• aerobic incubation method
• anaerobic incubation method
• air‐drying
• air‐dry storage

Notes

Journal Paper No. J‐11966 of the Iowa Agric. and Home Econ. Exp. Stn., Ames, Iowa. Projects 2655 and 2672.