Changes in physical properties and micromorphology of andosol induced by cultivation and soil management on sloped eroded upland field in Tsumagoi village [Japan]
1995
Arakawa, Y. (Tsukuba Univ., Ibaraki (Japan)) | Higashi, T.
This research was conducted on the field of Andosols (Umbric Andosols) under cabbage cultivation and an immediately adjacent uncultivated site in Tsumagoi, Gunma prefecture. Changes in soil physical properties and micromorphology induced by cultivation and soil management were investigated. The volume of solid phase and the bulk density of the soil samples increased and their hydraulic conductivity decreased with cultivation and management. Soil was compacted not only at the plow layer and just below it but also at the Bw horizons (down to 90cm depth). Soil aggregate-size distribution distinctly changed at the plow layer and just below it in the two pedons from cabbage cultivation. Soil compaction resulted in an increase in the mean-weight diameter of aggregates. While the decrease in that varies of aggregates could be attributed to the tillage and erosion processes. However, the aggregate-size distribution did not reflect physical changes in the Bw horizons. When corresponding sub-horizons were compared, macroporosity in soil thin section was smaller in the pedons under cabbage cultivation. Degrees of the decrease depended on horzons and pore types as follows. Channels distinctly decreased at the Ah3 horizon, just below the plow layer. Planes distinctly decreased at the BA and Bw1 horizon. Packing voids/vughs apparently decreased throughout the sub-horizons. The proportion of pores too small for the present analysis of the thin sections was similar in both cultivated and uncultivated pedons
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