Asian Anthroscapes: China and Taiwan

Anthroscapes are important in the assessment of human-induced land degradation. In case of soils affected by land use changes in large-scale farming, the anthropogenic processes have been created in China for over a few thousands years. The Chinese started to use soil for crop production as early as in the Stone Age. Soil properties in China and Taiwan have been greatly influenced by various anthropogenic processes to form anthroscapes. Paddy soils or rice-growing soils are more than 30 million hectares, distributed in China and Taiwan, which are one of the world’s most important soil resources for food production. According to the Chinese Soil Taxonomy [ISS/CAS (Institute of Soil Science, Chinese Academy of Sciences) (ed.) (2001) Chinese Soil Taxonomy. Science Press, Beijing, 203p], Anthrosols meet the requirements of the combination of horizons, including anthrostagnic, fimic, siltigic and cumulic epipedons and the hydragic horizon. The changes of soil characteristics after planting rice are degradation of soil organic matter (SOM), redistribution of exchangeable bases, translocation and segregation of iron (Fe) and manganese (Mn) by the cycling of reduction and oxidation processes, as well as decomposition and synthesis of clay minerals. The genetic horizons of paddy soils in China and Taiwan include a cultivated gray horizon, a plowpan, a percogenic horizon, and a plinthitic horizon or illuvial horizon with various redoximorphic features. The landscape position is the major factor to control the duration of saturation and reduction in the paddy soils of Taiwan. An anthrogleyic epipedon in Taiwan was also common in the surface horizon in paddy soils. Irrigation has induced the enrichment of the soil organic carbon (SOC) stock in the paddy soils. The free Fe contents of paddy profiles tend to be increased as the length of cultivation history increases in China, but this trend is much less profound in non-paddy profiles.