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A Century of Soil Development in Spoil Derived from Loess in Iowa
Author(s) -
Hallberg George R.,
Wollenhaupt Nyle C.,
Miller Gerald A.
Publication year - 1978
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1978.03615995004200020028x
Subject(s) - loess , silt , total organic carbon , horizon , soil water , organic matter , soil science , environmental science , soil horizon , loam , soil organic matter , bulk density , vegetation (pathology) , pedogenesis , geology , mineralogy , environmental chemistry , chemistry , geomorphology , mathematics , medicine , organic chemistry , pathology , geometry
During the past century well‐drained soils have formed in leached loess spoil materials under prairie vegetation along railroad cuts in Iowa. The spoil material was deposited on an existing Tama Variant soil which reveals the effects of 100 years of burial. In 100 years' time a 31‐cm A horizon has developed in the spoil, available phosphorus recycling has been measured, and the translocation and accumulation of illuvial clay and fine silt has occurred. The organic carbon content reached a maximum of 2.6% and exceeds 0.58% to depths of 40 to 46 cm. This 100‐year‐old A horizon, however, does not meet the color criterion for a mollic epipedon. Organic carbon content seems to build up rapidly in the first 30 to 50 years of soil development. After this time a slower more steady‐state rate of increase seems to take place. In 100 years' time the buried soil shows a 1% decrease (from 2.6 to 1.6%) in organic carbon in the upper 20 cm. Most of this difference resulted from the degradation of fibrous organic matter after burial. Accompanying this loss of organic matter is an increase in bulk density, which has impeded soil water movement. This density contrast has enhanced the accumulation of illuvial clay and fine silts in both the lower portion of the 100‐year‐old soil and in the buried A horizon.