Effects of interchangeable potassium on the permeability of a soil of Manfredi (Province of Córdoba)

Abstract

Utilizing percolation techniques in soil treatment with solutions of calcium and potassium chlorides, with the purpose of incorporating definitive cuantities of exchangeable potassium and in competing the permeabilities, the influence of exchangeable potassium on permeability was studied, The results are in agreement with those obtained by the authors in previous experiments, which showed that exchangeable potassium contributed to impair the physical conditions of soils. In the soil tested a Brunizem intergrate to Chestnut, the relative permeability after seven hours of water percolation was of 100:81:33:28:13 and 1,8, when the respective percentages of exchangeable potassium were 5,8: 11,5:22,0:32,9:38,6 and 60,4. Aumenting the proportion of exchangeable potassium, increased the turbidity and coloration of the percolates, showing a marked effect of the cation on dispersion and migration of clay and humic colloids. On addition to the soil of 0,5 % calcium carbonate, the final percentage of exchangeable potassium was reduced to 3,6; in the permeability tests, all perco'ates were limpid and colourless. The permeability was maintained constant and after seven hours of percolation was 2,6 and 3,0 times greater than that of the soil without calcium carbonate with exchangeable potassium percentages of 5,8 and 11,5 (natural soil), respectively. There results add new objections to those expressed by the authors in previous works, about the experiments on which the U. S. Salinity Laboratory sustains the point of view that potassium has little or no effect on soil physical conditions. The accomplished findings may contribute to a better understanding of the behaviour of soils occupying extensive areas in Argentina, which have exchangeable potassium contents between 12 and 16 %.