Cation exchange capacity of some tropical soils of Puerto Rico

Abstract

Data are presented here for the total exchange capacity of 81 soil samples in Puerto Rico and for available cations: Calcium, magnesium, potassium, and sodium, in 30 soil samples. The soils analyzed were representative of the following 13 groups: Rendzina, Wiesenboden, Reddish Brown, Reddish Chestnut, Reddish Prairie, Gray Brown Podzolic, Red and Yellow Podzolic, Reddish Brown Lateritic, Yellowish Brown Lateritic, Ground Water Laterite, Laterite, Lithosols, and Alluvial. Exchangeable bases are also reported for some soils in the Chernozem group. The highest value obtained for total exchange capacity was about 64 milliequivalents per 100 gm. of dry soil for a Rendzina and the lowest was about 2 m.e. for a Laterite. There is a wide difference between the minimum and maximum values of total exchange capacity for the various soil groups. Weathering had been active in the podzolic and more so in the lateritic group. The highest value for total exchangeable bases was over 60 m.e. for an Alluvial soil and the lowest was less than 2 m.e. for a lateritic soil; these contained 80 and 32 percent, respectively, of exchangeable calcium.