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Land use effects on soil crusting and hydraulic response of surface crusts on a tropical Alfisol
Authors:R M Bajracharya  R Lal
Abstract:Soil surface crusting, a common phenomenon on cultivated soils, has major implications for agriculture and the environment because of its effects on soil hydrological properties, erosion and crop establishment. The objectives of this study were to evaluate land use controls on crust formation and the hydraulic response of soils to crust development for a Patancheru series soil (clayey skeletal, mixed, isohyperthermic Udic Rhodustalf) in south‐central India. Soil aggregates, obtained from cultivated (PL) and naturally vegetated fallow (NV) land, were packed into sample trays and subjected to laboratory rain simulation to form crusts. Thin sections and visual observation indicated that crust development reached a more advanced stage in the PL case compared with NV following 90 min of rain at 40–80 mm h?1 intensity. This was reflected in a thicker crust layer with fewer voids in the former and a less smooth surface with partially disintegrated aggregates in the latter. The hydraulic response of the soil surface with the progression of crust development indicated a more permeable and less dense crust formed on NV than on PL soil. The results suggested that NV soil aggregates were more stable and that crust formation is more gradual for stable aggregates compared with the less stable PL aggregates. A structural crust‐type formed on the Patancheru soil by means of parallel subprocesses involving translocation and illuviation of aggregate disruption by products, and raindrop compaction and particle rearrangement. Copyright © 1999 John Wiley & Sons, Ltd.
Keywords:surface sealing  crust formation  soil thin section  rainfall simulation  micromorphology
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