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Paleopedological investigation of three agricultural loess soils on the loess plateau of china

Xiubin, He, Keli, Tang, Junliang, Tian, Matthews, John A.
Soil science 2002 v.167 no.7 pp. 478-491
A horizons, Argiustolls, Entisols, Haplustepts, Ustalfs, agricultural history, agrochemicals, anthropogenic activities, anthropogenic soil types, irrigation, loess, loess soils, microstructure, mineralogy, paleosolic soil types, palynology, radiocarbon dating, soil formation, soil properties, vegetation cover, China
Paleopedology is important for a proper understanding of the agrochemical and agroenvironmental behavior of surface (nonburied) paleosols. A long agricultural history on the Loess Plateau of China has caused extensive destruction of natural vegetation cover and resulted in profound modification of the original soils. Chinese soil scientists have called them agricultural loess soils and termed them Lutu soil, Zhong Heilutu soil, and Qin Heilutu soil, with variations of profile properties from the southeast to the northwest. The present paleopedological investigation was conducted in three typical profiles at three locations along a south-north transect across the Loess Plateau. New data and evidence of mineralogy, micromorphology, palynology, soil properties, and radiocarbon dating indicate that the so-called agricultural loess soils are Holocene paleopedosedimentary complexes combined with human disturbance, which consist of a paleosol layer developed in the middle Holocene and a cover layer of human disturbed fresh loess developed in the later Holocene. The pedogenetic types of the paleosols varied from Ustalfs to Argiustolls and Haplustepts (in the U.S. system) along the S-N transect, with paleo-bioclimatic pattern of the middle Holocene. The cover layers (Ap horizons) are newly deposited loess of the later Holocene, 10 to 25% of which in the south area was caused by human activities such as application of plaggen manure and irrigation with sediment-rich water. It has also has been affected by modern pedogenesis, and, therefore, it could be classified as a kind of Entisol or anthropogenic soil.