1. Pasture soil was found to be characterised by relatively high ammonia and low nitrate-nitrogen content during the main growing period (May-September). Applications of sulphate of ammonia while initially raising the ammonia and nitrate-nitrogen levels, ultimately led to a lowering. The effect of irrigation during the spring, when the soil moisture content was high, was to depress the ammonia and nitratenitrogen levels, but during the dry summer months and subsequently the levels were appreciably raised.
2. A small though definite periodic change in the reaction of normal grassland soil took place during the season, the soil being most acid during the summer. Added sulphate of ammonia slightly accentuated the change, and the return to normal in the autumn was not quite attained.