ABSTRACT
In sustaining the soil quality, soil salinization has become a major challenge due to the increasing salinity rate of 10% annually. Despite, the serious concerns, the influence of soil amendments on microbial communities and its related attributes have limited findings. Therefore, the present study aims to investigate the potential of three various biochars, digestate (DI), and its compost (COM) in reclamation of saline soil under closed ecosystem. The decrease in the pH was displayed by lignite char, and electrical conductivity by lignite char plus COM addition among all the treatments. The subside in Na +, with a significant rise in K +, was exhibited in soils amended with DI plus DI biochar as a combined ameliorate over control. The negative priming effects on native soil organic carbon (nSOC) due to the decreased substrate bioavailability, in corn straw and DI biochars ameliorates were noted. The urease and alkaline phosphatase activity were pronounced higher in COM. However, the catalase and fluorescein diacetate activity were greater in lignite char plus DI and COM respectively. The co-addition of biochar and organic substrates shifted microbial community, is in correspondence with the relative abundance of the phylum. Overall, the abundance of Firmicutes and Actinobacteria was higher in soils under a combination of lignite char with DI and COM respectively. Likely, the abundance of Euryarchaeota was dominant in the co-application of corn straw biochar and DI. Redundancy analysis revealed the intactness between bacterial genera and their metabolisms with K +, and Mg 2+. PICRUSt disclosed the enhanced metabolic functions in soil with amalgam of DI and its biochar. The findings showed that the application of DI and its biochar mixture, as an amendment could be a better approach in the long-term reclamation of saline soil.
Subject(s)
Microbiota , Soil , Carbon , Charcoal , Soil MicrobiologyABSTRACT
Macroalgae biomass has been considered as a promising feedstock for biogas production. In order to improve the efficiency of anaerobic digestion (AD) of macroalgae, semi-continuous fermentation was conducted to examine the effects of organic loading rate (OLR) on biogas production from Macrocystis pyrifer. Results showed that, under OLRs of 1.37, 2.74, 4.12 and 6.85kgVSsubstrate/(m3·d), the average unit biogas yields were 438.9, 477.3, 480.1 and 188.7mL/(gVSsubstrated), respectively. It indicated that biogas production was promoted by the increased OLR in an appropriate range while inhibited by the OLR beyond the appropriate range. The investigation on physical-chemical parameters revealed that unfavorable VFAs concentration, pH and salinity might be the main causes for system failure due to the overrange OLR, while the total phenols failed to reach the inhibitory concentration. Microbial community analysis demonstrated that several bacterial and archaeal phyla altered with increase in OLR apparently.
