Physical constants in soils of northwest Himalayas developed under different bio-sequences

The data on various physical constants have been elucidated in soil samples of eighteen soil profiles representing three bio-sequences of north-west Himalayas. Soil particle and bulk densities showed statistically inverse relationship with organic carbon content. The particle density was correlated with biotite mica and ferromagnesian minerals content. The main factor responsible for a large variation in water holding capacity and volume expansion of soil was the amount of organic and inorganic colloids rather than their kinds. Both of these constants revealed significant positive correlation with organic carbon content. Their values also appeared to be affected by the amount of clay minerals especially smectite and amorphous clays. The pore space of these soils was highly significantly and positively correlated with organic carbon as well as silt+clay and not with clay alone. The bio-sequences markedly influenced the values of various physical constants.