Publikationsdatum:
1955-04-01
Beschreibung:
A comparison of methods of measuring the structural condition of cultivated surface soil was made for two important East African soil types.The soil samples were drawn from two field experiments: (i) a tillage trial in coffee on a porous red lateritic clay soil of recent volcanic origin; (ii) a rotation trial for cotton, on a red sandy lateritic loam of granitic origin.Of the measurements on soil cores, total porespace and field capacity (⅓ atmosphere) showed little change, while percolation rates, free-draining pore-space and a new rainfall acceptance test all reflected the observed field behaviour of the soils, and showed fairly close and highly significant correlation. Field sieving of dry clods gave highly significant differences in the lateritic clay, the stronger clods indicating the poorer soil condition. Drysieving for ½ mm. crumb was ineffective, as was wet-sieving after wetting under vacuum. Wetting by immersion gave some differences between treatments, but higher variability and no significant correlation with free-draining pore-space. Wetting by rainfall impact on dry crumbs gave the best wet-sieving tests on the clay soil. Different sieving techniques gave inconsistent results on the sandy soil. Crumb structure measurements are not efficient indications of structural conditions on these soil types, which are of wide occurrence in tropical countries.
Print ISSN:
0021-8596
Digitale ISSN:
1469-5146
Thema:
Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
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