Rhizosphere Soil Microbial Survival States and N-Related Process during Riparian Plant Dormancy: Influences of Plant Locations and Plant Species

The plant dormancy period in the riparian zone affects the activity of microorganisms and their related nitrogen (N) process, which necessitates an investigation of the influence of the dormancy period on the microbial community. This study sampled two groups of soils (ashore and offshore soils) of two typical plants (Acorus calamus, Canna indica) in rhizosphere soils and bulk soils during the dormancy period to study the microbial communities. The results suggested that in ashore soils, especially in Canna indica soils, there was a lower abundance of N-related genes (4.79 × 106 copies/g) due to relatively competitive ecological niche competition because of possible sufficient substrate. Therefore, microbial communities still play a major role in the removal of N-related nutrients during plants’ dormancy period. In addition, the results also showed that during the plant dormancy period, the cell necrosis processes accounted for relatively lower proportions (15.75%, 7.54%, 21.46%, and 5.23% in ashore and offshore Canna indica and ashore and offshore Acorus calamus, respectively), suggesting an unexpected fairly strong microbial survival ability in the dormancy period compared to the commonly expected weak microbial state. This high microbial vitality provides us insight into the restoration of riparian soils during the plant dormancy period

Rhizosphere Soil Microbial Survival States and N-Related Process during Riparian Plant Dormancy: Influences of Plant Locations and Plant Species

The plant dormancy period in the riparian zone affects the activity of microorganisms and their related nitrogen (N) process, which necessitates an investigation of the influence of the dormancy period on the microbial community. This study sampled two groups of soils (ashore and offshore soils) of two typical plants (Acorus calamus, Canna indica) in rhizosphere soils and bulk soils during the dormancy period to study the microbial communities. The results suggested that in ashore soils, especially in Canna indica soils, there was a lower abundance of N-related genes (4.79 × 106 copies/g) due to relatively competitive ecological niche competition because of possible sufficient substrate. Therefore, microbial communities still play a major role in the removal of N-related nutrients during plants’ dormancy period. In addition, the results also showed that during the plant dormancy period, the cell necrosis processes accounted for relatively lower proportions (15.75%, 7.54%, 21.46%, and 5.23% in ashore and offshore Canna indica and ashore and offshore Acorus calamus, respectively), suggesting an unexpected fairly strong microbial survival ability in the dormancy period compared to the commonly expected weak microbial state. This high microbial vitality provides us insight into the restoration of riparian soils during the plant dormancy period

Fractions and spatial distributions of agricultural riparian soil phosphorus in a small river basin of Taihu area, China

Soil samples were collected from three different ranks riparian soil profiles in a small river basin of Taihu area in China. The method of modified Hedley phosphorus sequential fraction was employed to characterize soil phosphorus fractions. The results showed that the riparian soil total phosphorus (TP) contents, organic phosphorus (OP) and inorganic phosphorus (IP) of the basin ranged from 234.98 to 542.29, 49.76 to 73.81, 161.17 to 492.54 mg kg−1, respectively. HCl-Pi, NaOH-Pi and residual Pi were the major part of IP, accounting for 28, 28 and 26% of IP respectively, but NaHCO3-Pi was accounted for 18% of IP. Overall, the various forms of phosphorus, except for Residual P, had a decreasing trend with soils depth. The vertical distributions of TP and IP had same rank order (Riparian Hejiabang > Riparian wuxidang > Riparian Yincungang), while the opposite trend was observed for OP. Surface soils in Riparian Yincungang had lower SOM (soil organic matters):OP ratios than Riparian Wuxidang and Riparian Hejiabang, reflecting the higher probability of OP mineralization in uncultivated soils. Besides, there was significant correlation between phosphorus fractions and SOM, bulk density and capillary porosity