Pedodiversity: A Case Study Based on 1:1 Million Scale SOTER of Shandong Province, China

The diversity of soils derived from different parent materials and developed on different terrains inShandong Province, China, was analyzed with the theory of pedodiversity using a 1:1000000 scale soilsand terrain digital database (SOTER) of Shandong Province in a geographical information system (GIS)environment. Diversity index of soils derived from different parent materials followed the sequence of igneousrock ＞ sedimentary rock ＞ metamorphic rock ＞ unconsolidated material. Diversity index of soils developedon different terrains followed the sequence of plain ＞ medium-gradient mountain ＞ medium-gradient hill＞ valley floor ＞ medium-gradient escarpment zone ＞ depression ＞ high-gradient mountain. Abundancedistributions of these soil groups matched the logarithmic normal distributions.

Pedodiversity analysis in Hainan Island

Diversity indices and abundance distribution models are statistical tools which ecologists have applied for decades for analyzing the intrinsic regularities of various ecological entities. In this work, we have applied these techniques to use the notions such as pedodiversity (as an example of geodiversity in a broad sense), in order to detect the differences and similarities between both natural resources, biological and non-biological. The discussion has mainly been conducted through the study of landform based pedodiversity analysis applied to SOTER digital databases in Hainan Island, China. The main analytical methods include indices of richness S that are the number of the categories (SOTER units relating to different soils in this work), indices based on proportional abundance of categories H' and E which are not only the number but also their relative abundance (in our case, the relative area occupied by each pedotaxa) is taken into account, models of the distribution of abundance of categories that provide the most complete description but also the least abridged and GIS mapping to show the spatial variation digitally.

Pedodiversity: a controversial concept

The concept of pedodiversity and its measurement methodology proposed and developed by Ibá?ez research term is introduced. An attempt to apply pedodiversity to analyze spatial soil variation and distribution patterns on the global scale is briefly demonstrated. Furthermore, constructive comments and criticisms on pedodiversity and its measurement from the noted pedologists and ecologists are outlined. Finally, potential applications of pedodiversity in soil science and other relevant disciplines are discussed.

A pedodiversity pattern: taxonomically established soil orders in China

Under the framework of Chinese Soil Taxonomy, all the 14 established soil orders including Histosols, Anthrosols, Spodosols, Andisols, Ferralisols, Vertisols, Aridisols, Halosols, Gleyosols, Isohumisols, Ferrisols, Luvisols, Cambisols and Primosols, forming a complicated pedodiversity pattern resulted from both various natural conditions and long history of human activities, are introduced with brief descriptions. At the end of the paper, the selected references in English are listed for foreign readers to get further information in detail if needed.

Correlative comparison of pedodiversity and land use diversity between case areas from the developed east and less developed central China

Two typical provincial capitals （Nanjing and Zhengzhou） and two counties （Rugao and Yuanyang） in east （Jiangsu Province） and central （Henan Province） China were chosen respectively as the developed and less developed comparative cases for pedodiversity and land use diversity correlative analysis by borrowing the recently better developed pedodiversity methodology. Land use classification was worked out using remote sensing images in three different periods （1986-1988, 2000-2001 and 2004-2006） for these studied case areas before the calculation of the constituent diversity index and spatial distribution diversity index modified after Shannon entropy in 2 kmx2 km grid scale of the soil and land use pattern were conducted and then a connection index was proposed to evaluate the relationship between soil and land use diversity. Results show that during the years from 1986 to 2006, the composition and spatial distribution of regional land use pattern had changed greatly. The agricultural land area of all the studied case areas decreased obviously in which Nanjing has the highest decrement of 895.98 km2 mainly into urban use while the other land use type area changes show the same trend. The connection index of four typical soil family types and typical urban land use types, i.e., urban construction land, transportation land and industrial and mining area all increased in this period. In the studied case areas, there is the highest soil constituent diversity in Zhengzhou at 0.779 while the simplest soil constituent diversity in Rugao at 0.582. Meanwhile we have higher land use diversity in the more urbanized Jiangsu Province than Henan Province, Nanjing is ranking the first that has been getting higher and higher in the three periods at 0.366 in 1986-1988, 0.483 in 2000-2001 and 0.545 in 2004-2006. Finally, the connection index figures to evaluate the relationship between soil and land use diversity of the studied areas were compared to show the similar phenomenon that this figure grows fastest in Nanjing followed by Zhengzhou and other places.

Soil genetic erosion: New conceptual developments in soil security

In the last decades,in some Mediterranean areas,pedodiversity decreased mainly due to pedotechnique application in large-scale farming that transformed original soils into Anthrosols.Supporting the consideration that soils can be considered as living systems,the original concept of'soil genetic erosion'is re-proposed.Data,extrapolated and modeled from a Soil Information System in a study case representative of a Mediterranean landscape,predicted that most of the soil types would disappear in few years leading to a decrease of the soil diversity and originating soil genetic erosion.This circumstance is intentionally here told in form of a story where the fairy tale characters are some roils facing extinction in the landscape.Soil genetic erosion could result in a negative impact on the environment because it reduces the soil's security through a drastic reduction of the soil ecosystem services with a decrease of the immaterial benefit for the environment.The conviction that soils,as well as animals and plants,are living bodies,and pedodiversity is equally important as biodiversity in maintaining sustainability and ecosystem services,might truly attract the attention of the public opinion.Besides,focussing more on the soil economic dimension and strengthening the assignation of'economic value'to the soil ecosystem services,also politicians and administrators could increase their interest in soil security.

The“genetic erosion”of the soil ecosystem

This paper takes into consideration the influence of human activities on the loss of pedodiversity in a Mediterranean area due to large scale farming.In particular it examines the quantitative and qualitative soil changes in a period of 53 years(from 1955 to 2008)evaluating the loss of soil diversity at soil subgroups level of the USDA Soil Taxonomy system.The following indices were used:richness;Shannon’s diversity index;Simpson diversity index;Shannon’s evenness index;Simpson’s evenness index.In this case study,considering what we observed in time,the human intervention in soil transformation could increase the diversity in the landscape in an initial phase,but forwarding by large scale farming the result is a huge loss of pedodiversity in time,as diversity indices remarkably have shown.This analysis enabled identification of disappeared soil types,with their unique history of formation.In our opinion this strongly reflects a sort of“genetic erosion”of the soil types,resulting in a substantial weakening of the whole pedo-ecosystem.