Chapter 7 Physical Characteristics of Volcanic Ash Soils

摘要: Publisher Summary Volcanic ash soils have many unique physical properties that are attributable directly to the of parent material, noncrystalline materials formed by weathering, and soil organic matter accumulated during formation. These include dark color, difficult clay dispersion, consistence, low bulk density, high water holding capacity. Soil color is most striking feature observed for volcanic soils, especially their A horizons. Andisols typically display a large difference in texture when comparing field laboratory determination methods. Noncrystalline play an important role as cementing agents react with excess amount sodium hexametaphosphate. Furthermore, each inorganic colloids shows different point zero net charge, so complete dispersion mineral particles virtually impossible. generally densities development highly porous structure. usually show degrees stickiness, plasticity, hardness result from abundance and/or matter. also provide excellent environment root growth. well-developed structure resulting porosity range pore sizes retain varying tensions.