Published online by Cambridge University Press: 27 March 2009
1. Soil samples were incubated at 60% W.h.c. at 20° C. and leached after 8 and 20 weeks. On subsequent incubation, the rate of nitrate production in the leached samples was greater than that in unleached control soils. The increase in nitrate production seems to be due to an increased rate of ammonification.
2. Adding 100 p.p.m. of nitrate nitrogen to the soil before incubating had no effect on mineralization.
3. Adding a leachate of incubated soil to new soil samples reduced the rate of mineralization on incubation. This reduction is not due to nitrate or any other anion, since deionized leachate was equally effective.