Buffering capacity of soils under different land use systems in southern transitional Zone of Karnataka

摘要

Buffering capacity of soils was more in surface soil than in subsurface soil in all land use systems. However in subsurface horizons buffering capacity increased with depth in all the soil profiles due to increase in both clay and free iron oxides contents (Baruah and Barthakur, 1998). Among the soils studied buffering capacity was comparatively more in the soil under mixed forest [0.76 C.mol (p~+) kg~(-1)] land use system and this could be attributed to the high organic matter, clay, free iron oxides and bicarbonates content (Brady, 1990). Whereas the soils under sugarcane and tobacco land use systems recorded lowest [0.45 and 0.47 C.mol (p+) kg~(-1) respectively] buffering capacity due to their coarse textured nature with low content of both freeiron oxides and organic matter. Correlation study indicated that buffering capacity of soil was significantly and negatively correlated with both the sand (-0.703**) and exchangeable acidic cations (-0.522**). While with silt (0.551**), clay (0.583**), soil organic carbon (0.489**), pHw (0.641**) free iron oxides (0.528**), exchangeable basic cations (0.472**), bicarbonates a (0.612**) and dehydrogenase (0.670**) it was positively and significantly correlated.