Soil chemical properties and distribution of sclerotium grains in forest soils, Harz Mts., Germany

Abstract

Relationships between the distribution of fungal sclerotium grains and soil chemical properties were studied in forest soils of Podsole, Braunfahlerde, and Braunerde-Podsoles in Harz Mts., Germany. Development of sclerotium grains ns was dominant in surface horizons (Ah, E horizons) within a 10-cm depth and weight density of grains ranged from 0.01 to 4.99 g kg^-1 soil. The SEMI-EDX analysis proved that the weight percentage (excluding C and N) of Al₂O₃ was 39.8–63.9% inside the grains. The content of elgosterol, a biomarker of viable fungal biomes, showed good correlations with weight density of sclerotium grains in grain-detected soils. The sclerotium. grains were likely to be formed in soils with high ratios (>0.6) of organic bonding Al (Al_p) to amorphous Al (Al_o), and with high contents of exchangeable Al (Al³⁺) (>0.54 g kg^-1). The content and state of active Al were believed to be responsible for the development of sclerotium because sclerotium grains were not detected in acid soils which had lower levels of free colloidal Al (Al_d, Al_o, Alp). We believed that the intensive clay destruction associated with past lessivage process induced the absence of free colloid Al in such forest soils.

Key Words:

• density of sclerotium grains
• elgosterol
• exchangeable Al
• pH value
• Podsole