Rapid procedures for preparing soil and KCL extracts for 15N analysis.

Abstract An apparatus for grinding plant and soil samples to <250um for 15N analysis is described. This inexpensive and easily constructed roller grinder uses bottles for grinding individual samples, thus eliminating the potential for cross contamination. The unit running over‐night is capable of grinding 70 samples. In addition a method is described for diffusing NH4 + and NO3 onto filter paper for subsequent 15N analysis. This method utilizes disposable test tubes and an incubator‐shaker to help speed the diffusion process. At low A% I5N (2–3%) a diffusion period of 7 days is sufficient for total 15? recovery. At an A% 15N of 8% the diffusion period needed to be extended to 10 days for total recovery.