Soil pH's were evaluated at three time intervals following land clearing at two locations in the Matanuska Valley. Seasonal fluctuations of pH values over a seven‐year period as determined in water (pHw,) and 0.01 M CaCl2(pHs) were additionally evaluated at these locations. A statistical rise in soil pH occurred at both locations with clearing and subsequent cultivation. Soil reaction differences related to season and year were not consistent and were not related to a definite pattern. No relationship between monthly or seasonal precipitation and the soil reaction was found. The correlation coefficient between pHwand pHswas highly significant. Work of other investigators is discussed in the interpretation of the data collected.