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Titration Curves and Buffering Capacities of Hawaiian Soils
|Title:||Titration Curves and Buffering Capacities of Hawaiian Soils|
Sherman, G. Donald
soil chemical properties
|Issue Date:||May 1950|
|Publisher:||Hawaii Agricultural Experiment Station, University of Hawaii|
|Citation:||Matsusaka Y, Sherman GD. 1950 Titration curves and buffering capacities of Hawaiian soils. Honolulu (HI): Hawaii Agricultural Experiment Station, University of Hawaii. 36 p. (Technical Bulletin; 11)|
|Series/Report no.:||Technical Bulletin|
|Abstract:||In the development of a liming program for the acid soils of the Hawaiian Islands, it was found that soils of the various great soil groups varied greatly in their lime requirement for correction of similar degrees of acidity. This variation in lime requirement appeared to be associated with the differences in the buffering capacities of the soils. Titration curves were made on more than a hundred soils selected from the typical profiles of the soil families belonging to the various great soil groups. The results of this study have justified the following conclusion regarding the nature of the titration curves and buffering capacities of the tropical and subtropical soils of the Hawaiian Islands:
The buffering capacity of Hawaiian soils was much lower than that found for soils of the temperate regions. The buffering capacity of the soils of the different great soil groups varied greatly; however, there was very little variation in the degree of buffering exhibited by the soils of the different soil families of each group. Each soil group has a typical titration curve. The soils of the low humic latosol and humic ferruginous latosol have the lowest buffering capacity, and the soils of the hydroI humic latosol and brown forest groups exhibit the greatest degree of buffering.
The organic matter fraction of the soil affects the degree of buffering above soil reaction of pH 5.5. It is most "active" in neutral and alkaline portions of the titration curves. However, the organic matter fraction does not influence the nature of the curve. The general character of the titration curve is determined by the nature of the clay minerals. The kaolinite and iron oxide clays give rise to titration curves having a low buffering capacity and montmorillonite and hydrated aluminum oxide clays give titration curves having a high buffering capacity. The silica-sesquioxide ratio of the clay fraction of the soil or the quantity of clay in the soil was not related to the degree of buffering exhibited by the titration curve of the soil. This is probably due to the large amount of "free oxides" found in these soils. There is a direct relation ship between the cation exchange capacity of the soil and its buffering capacity. The higher the cation exchange capacity the greater buffering would be exhibited by the titration curve of the soil.
|Appears in Collections:||Technical Bulletin, 1943 - 1980|