Affect of application of black soils over a native red soils on soil physical and physico-chemical properties

Abstract

Field wise geo-referenced morphological, physico-chemical characteristics and nutrients status by application of applied black soils over native red soils of semi arid regions of Tamil Nadu, India were studied. The physiography of study area was nearly level to gently sloppy. The textural class of fine earth fraction was coarse textured gravelly sandy loam and sandy clay loam in the surface soils of native red soils and sandy clay loam in sub-surface horizons of applied black soils over native red soils, whereas clayey in surface layers of applied black soils. The clay content was ranged from17.4 to 19.6 percent in surface and 19.8 to 21.4 percent in subsurface soils of native soils. The sub surface horizons of applied black soils over native soils, clay content ranged from 21.1 to 25.8 percent. The surface soils exhibited weak medium fine granular structures in native soils whereas in subsurface soils of applied black soils over native soil shown weak to medium subangular blocky structures. The moisture retention at field capacity (33kpa) by application of applied black soils over native red soils varied from 29.2-30.4 and 19.8-22.7%, permanent wilting capacity (1500kpa) varied from 14.8-16.9 and 7.6-9.2%, available water capacity varied from 13.6-15.5 and 11.9-14.1% respectively in both the surface and sub surface soils. The moisture retention at field capacity varied from 16.2-19.4 and 16.2-18.5%, at permanent wilting capacity varied from 5.4-7.6 and 4.9-7.8% and the available water capacity varied from 10.2-11.6 and11.3-11.9% in both the surface and sub surface soils of native red soils respectively. The moisture retention at field capacity, permanent wilting point and available water capacity were high in sub surface soils of application of black soils over the native red soils at different soil water suctions than native surface and subsurface soils. Exchangeable bases in all the soils were in the order of Ca++>Mg++>Na+>K+ on the exchangeable complex. The CaCO3 content of native red soils (5.5 to 7.8 and 6.0 to 9.0 g kg-1) and in applied black soils ranged from 21.0 to 42.0 and 6.5 to 11.8 g kg-1 in both the surface and sub surface soils respectively.