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THE EFFECT OF ORGANIC MATTER ON CRUMB STRUCTURE
Author(s) -
EMERSON W. W.,
DETTMANN MARGARET G.
Publication year - 1959
Publication title -
journal of soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.244
H-Index - 111
eISSN - 1365-2389
pISSN - 0022-4588
DOI - 10.1111/j.1365-2389.1959.tb02345.x
Subject(s) - arable land , grassland , environmental science , soil science , agronomy , geography , agriculture , archaeology , biology
Summary Tests made on soil crumbs from nearby long‐term arable and grassland fields have shown that (a) the rate of water uptake of dry crumbs at 98 per cent. relative humidity was the same for arable and grassland crumbs and also grassland crumbs pretreated with H 2 O 2 ; (b) the degree of swelling of dry arable and grassland crumbs in water is the same. It is concluded that the crystalline swelling of the clay in soil crumbs is unaffected by the soil having been under grass. No difference could be observed in the general arrangement of the quartz and orientated clay in thin sections of arable and the corresponding grassland crumbs. From slaking and dispersion tests made on the natural crumbs and on remoulded crumbs formed by drying from a paste of the natural crumbs it is inferred that remoulding does not disperse the clay in either the grassland or arable crumbs, but does break‐up many of the aggregates between 50 μ and 2 μ diameter in the grassland crumbs. The natural arable crumbs were so weak that immersion wetting of the dry crumbs was sufficient in itself to cause this break‐up.