Variability in Some Physical Properties of Vertisols of Three Permanent Bench Mark Sites under Rice-wheat Cropping System in Jabalpur District, Madhya Pradesh, in India

The study was carried out for vertical characterization of soils at three permanent benchmark sites (Udna, Khamaria and Magarmuha) of Jabalpur district for their physical properties under the Rice-Wheat cropping system. Variability in the proportion of primary soil particles (texture), bulk density, distribution of different sized soil aggregates and mean weight diameter (MWD) of soil aggregates along the depths were studied as these influence the water and nutrients retention and release behaviour of soil. A total of 45 undisturbed soil samples were collected from selected sites at 0-20, 20-40, 40-60, 60-80 and 80-100 cm depths and brought to the laboratory for their characterization and the data thus obtained were analysed in split-plot design taking sites as main plot and depth as sub-plot treatments. Results showed that variability in the sand, silt and clay contents, bulk density, fractions of different size soil aggregate (>5.0, 5.0-2.0, 2.0-1.0, 1.0-0.5,0.5-0.25,0.25-0.1 and <0.10 mm) and mean weight diameter of soil aggregates were significant across the sites and soil depths. However, the interaction effect of sites and soil depth on the above properties was found non-significant except for fraction of < 0.1 mm size aggregate. It has been analysed from the study that sand, silt and clay contents, bulk density, fractions of different size aggregate and mean weight diameter of soil aggregates vary significantly (ρ=0.05) at spatially and vertically.