Preservation of common soil phytoliths in the northern temperate region: a case study from northeast China

We investigated the phytolith assemblage characteristics and preservation of soil phytoliths in nine soil types at 83 sites in northeast China. The results indicate that the phytolith assemblages from the nine soils are similar, particularly in terms of the content of the dominant short cell phytoliths, and elongate and lanceolate phytoliths. The phytolith indexes of aridity and water stress (Iph and Fs, respectively) have been proven to be effective in the temperate zone, and we find that values of Iph and Fs higher than 0.45 and 0.24, respectively, are characteristic of meadow steppe. However, there are differences in phytolith indexes amongst the different soil types. In addition, the preservation characteristics of phytoliths in different soil types are different, with phytolith preservation in zonal soils being better than in azonal soils. Morphotypes such as rondel, bilobate, lanceolate, blocky, tabular and bulliform are well preserved in the studied soils; however, other morphotypes, such as microhair, conical epidermal, silicified stomata and epidermal, are poorly preserved. Morphotypes such as saddle, trapeziform sinuate and elongate are moderately well preserved in the soils. The preservation characteristics of the same type of phytolith differ between the soil types. Thus, there are differences in the preservation of soil phytoliths amongst different soil types, which needs to be considered when soil phytoliths are used to produce quantitative palaeoenvironmental reconstructions.