VARIATION IN pH AND BUFFERING CAPACITY OF THE ORGANIC LAYER OF GREY WOODED SOILS

Abstract

The soils studied belong to the grey wooded (podzolic) soils as described by Moss and St. Arnaud (7). The pH of the soil was determined in the field, or within a few hours after sampling in the laboratory, using a Beckman pH meter with a combination glass electrode. The samples were prepared as a soil paste according to Doughty's method (4). In order to study the frequency distribution of pH values in individual soil layers, the acidity of 100 small and 100 large samples (approximately 3 cc. and 60 cc., respectively), taken at random from the F, H, and A soil layers within a 50 x 50 foot area, was determined at 20 different sites. Titration curves were constructed from data obtained by titrating samples of approximately 1 g. with 0.02 N HC1 and KOH. The results were calculated on a basis of 10 g. oven-dry (105°C.) weight. Buffering in each soil layer was studied by measuring the pH of individual 1-g. samples, and remeasuring the pH after a thorough mixing of different numbers (2 or 20) of these samples. The measured pH of the mixed sample was then compared with the calculated average. Data converted to ion concentrations were used to calculate the averages. Three soil layers at five