Micromorphological Features of Old Cultivated and Modern Soils in Guanzhong Areas, Shaanxi Province, China

• Published in: Agricultural sciences in China Vol. 5; no. 9; pp. 691 - 699
• Main Authors: PANG, Jiang-li, HU, Xuan-er, HUANG, Chun-chang, Zhang, Xu
• Format: Journal Article
• Language: English
• Published: College of Tourism and Environmental Sciences/Northwest Research Center for Historical Environment and Socio-Economic Development, Shaanxi Normal University, Xi'an 710062, P.R. China%College of Foreign Languages, Shaanxi Normal University, Xi'an 710062, P.R. China%College of Tourism and Environmental Sciences, Shaanxi Normal University, Xi'an 710062, P.R. China 01.09.2006
• Subjects: 关中地区; 有机成分; old cultivated soils; micromorphology; modern soil; Guanzhong areas
• ISSN: 1671-2927
• DOI: 10.1016/S1671-2927(06)60112-0

Using the data obtained from the LGT soil profile, this article attempts to illustrate the process of modem soil formation in the Guanzhong areas and its micromorphological features. The micromorphology is observed under a petrographic microscope, and its image is quantitatively measured by LEICAL Qwin 2.6 software. Micromorphological observations of the thin sections show that the assemblage of minerals in different horizons is very similar, which is mainly composed of Q and P1. However, there are obvious differences in C/F15μm ratio, mineral content, and coarse features. The pedofeatures is mainly composed of clay, calcite, and amorphous Fe. Ap horizon is characterized by abundant needleshaped secondary calcite, secondary clay, and earthworm fecal pellet. BC horizon is characterized by a large quantity of secondary calcite with various shapes. Bt1and Bt2 horizons are characterized by abundant clay hypocoatings and a small quantity of secondary calcite. All the results of this research suggest that Earth-cumulic Orthic Anthrosols consist of both the upper Ap horizon, which cause loessal dung and eolian dust deposition, and cultivation occurs simultaneously during the process of Ap horizon-formation, and the lower BC horizon, which is aeolian sedimentary at the time of relative aridity during late Holocene.