The relationship of the processes in the rhizosphere of common reed Phragmites australis, (Cav.) TRIN. ex STEUDEL to water fluctuation

摘要

Intermittent Lake Cerknica is characterised by extreme water level fluctuations. It is neither a lake, nor a terrestrial ecosystem. The decomposition processes in the rhizosphere of extended reed stands are essential for the entire ecosystem. The influence of intermittent water regime on the microbial activity and availability of nutrients in the rhizosphere in a terrestrial reed stand was investigated. The measurements revealed a relatively high soil water content, that was not related to underground water table. Mineralization processes in a soil profile were estimated by measuring microbial activity as electron transport system (ETS) activity and by nutrients in soil water. The microbial activity was determined in the whole depth profile. The highest ETS activity of a soil was 0.23 mg O-2 g DW-1 h(-1), while the average value was 0.05 mg O-2 g DW-1 h(-1). The values were not related to underground water table. All forms of nutrients were constantly present, showing no correlation with the soil water content. ANOVA revealed significant decrease of nitrate with depth, but not for nitrite, ammonium and ortho-phosphate.