Soil phytoliths in Larix gmelinii forest and their relationships with soil properties

Aims Ecosystems with higher latitude in the northern hemisphere are expected to face the largest loss of soil organic carbon (C) due to global warming. The concentrations, distributions, morphology of phytoliths and their associations with soil properties show fundamental significance in actually assessing the potential C sequestration of forest soils. Methods We examined soil phytolith contents and soil properties of Larix gmelinii forest from the Greater Khingan Mountains. ANOVA, bivariate correlation, regression analysis, principal component analysis and redundancy analysis were conducted to interpret the relations between soil phytoliths and soil properties. Results The soil phytoliths in the studied area were mainly elongate in shape with a mean content of 19.1 g kg(-1). The phytoliths had a significant correlation with phosphorus rather than potassium and nitrogen, while they had no correlation with soil water content. Soil phytolith storage in the cold temperate zone (41.0 t ha(-1)) was significantly higher than in the tropical and subtropical zones. Conclusions Soil phytolith storage in Larix gmelinii forest is affected by soil properties and climate, which have a certain relation with soil organic C, pH, nutrients and mineral elements. The C sequestration capacity of soils could be elevated by the increase of phytolith contents in the cold temperate coniferous forest. Analyses of small-sized and fragile phytogenic Si structures are urgently needed in future work as they are the most important drivers of Si cycling in terrestrial biogeosystems, which is very important to accurately quantify the phytoliths contents and the pool of C sequestered in phytoliths.