Preliminary Study On Soil Taxonomy Low-level Unit Classification In Northern Jiangsu

This study is part of the research of "Soil series survey in Northern Jiangsu and the establishment of the <<hinese soil series chi-Jiangsu Volume>>", which is a sub-topics of "Chinese soil series suevey and the establishment of <<hinese soil series chi>>"(item number:2008FY110600) from national basis work of the Chinese Ministry of Science.Genetic Soil Classification of China (GSCC) has promoted the development of Chinese soil science, and made a significant contribution to utilization of soil resources. However, as time passes by, some disadvantages of GSCC has been gradually exposed, such as classification ambiguity, lack of quantitative, and prone to the same soil of different names or same name of different soils, which could’t been made up. The development of Soil Taxonomy provides a way to solve those. After nearly three decades of research, Chinese Soil Taxonomy (CST) has established a complete system of senior classification units, and some plots in typical areas were studied based on CST. CST has made a great impact. But there have few studies about soil lower classification level. Soil scientists just proposed the principle of soil families and soil series classification, and determined the soil type according to that, while there was no specific classification method. At the same time, the northern region of Jiangsu province, as an important agricultural area, its soil data still remain in the country’s second national soil survey based on GSCC, and there is no study based on soil taxonomy. This paper studied the typical soils in northern region of Jiangsu province based on CST, and determined its position in CST; and selected a smaller plot, studied the influencing factor of soil series classification and soil series classification methods, established some soil series.This paper selected some typical soil species according to the country’s second national soil survey, excavated a number of soil profiles in the wild in accordance with the spatial variation of the pedogenic factors, such as topography, parent material and others. This research determined the diagnostic horizons and diagnostic characteristics of soils in northern Jiangsu province, and the soils’position in CST under the guidance of soil taxonomy. After testing the physical and chemical properties of soil in Xinyi plot, Jiangsu province, this paper selected the influencing factors of soil series classification using the related features of statistical software such as SPSS, EXCEL, and established some soil series through retrieval method.The follows are the main results of this study:(1)The soils in northorn Jiangsu province belonged to Anthrosols, Halosols, Argosols, Cambosols and Primosols. They have some diagnostic horizons, including Anthrostagnic epipedon, Albic horizon, Cambic horizon, Agric horizon, Hydragric horizon, Argic horizon, Calcic horizon and Salic horizon. And some diagnostic characteristics, such as L.C.of purplish sandstones and shales, L.C.of carbonate rocks, Lithic contact, Anthroturbic layer, Ustic soil moisture regime, Udic soil moisture regime, Anthrostagnic soil moisture regime, Gleyic features, Redox features, Thermic soil temperature regime, Calcaric property and Base saturation are present in the soils.(2)Using variance, correlation analysis and other methods, choose①the type, arrangement, thickness of characteristic horizons;②soil texture and③the content of organic matter to classify soil series.(3)The follows is the retrieve order of soil series classification:①Whether there are characteristic horizons, such as the layer of weathered material of the purple glutenite, layer of the ferromanganese glue spots, layer of lime tuberculosis and others in soil series control section, and their emergence depth.②Wether the texture of soil epipedon consistent, and the soil of different texture types are classified into different soil series.③According to organic matter gradice and the status of organic matter in soil epipedon, soil series are classified in accordance with four levels,>30、20-30、10-20、6-10(g/kg).