Halophyte Plant Communities Affecting Enzyme Activity and Microbes in Saline Soils of the Yellow River Delta in China

Abstract

The Yellow River Delta covers a large area of saline soil, which needs to be recovered urgently. As the main local halophytes Suaeda salsa, Phragmites australis, and Tamarix chinensis communities play an important role in the improvement of the soil micro‐environment. Therefore, we investigated the effect of these three salt‐tolerant plant communities on soil enzyme activity in the Yellow River Delta in China. Halophyte plant communities influence the soil micro‐ecosystem in the wetland by exerting effects on the physicochemical properties of the soil, and on enzymes and microbial community. In the soil these enzymes affect the redox potential (catalase) and cycling of carbon (dehydrogenase), nitrogen (protease, urease), and phosphorus (acid phosphatase). We analyzed enzyme activity and the relations between the activity of different enzymes, the physicochemical properties of the soil, and the microbial composition. The activity of five enzymes differed significantly between the plant communities. Soil salinity and microbial community composition all influenced enzyme activity. Catalase, protease and urease activity in the soil of the T. chinensis community was significantly higher than in the other two plant communities. Dehydrogenase and acid phosphatase activity were significantly higher in the soil of the P. australis community than in the other two communities. In the succession of the plant community from herbs to woody plants with different salt tolerance mechanisms, a large aboveground biomass may support the growth of soil enzyme activity and soil microorganism diversity. This study showed that the belowground processes were strongly related with plant community succession in salt marsh ecosystem.

Nutrients, microbial community structure and functional gene abundance of rhizosphere and bulk soils of halophytes

“…Enzyme activities were markedly higher in rhizosphere compared to control soil but all plants were not affected enzyme activities to the same degree (Dinesh et al, 2010). Such differences in biochemical parameters between rhizopshere and bulk soil have been previously described in different plant communities (Caravaca et al, 2005;Dinesh et al, 2010;Cao et al, 2014).…”

“…These results thus suggest for the first time that soil around the halophyte roots was enriched in nutrient compared to the bulk soil. Electrical conductivity of rhizosphere soil was low because succulent halophytes can absorb the soil salinity into its modified succulent leaves that can reduce the soil salinity (Cao et al, 2014). The state of nutrient condition in the rhizospheric soil of halophytes is totally different from that in non-halophytes (Liangpeng et al, 2007) as studied by previous researchers (Meo et al, 2003;Collignon et al, 2011;Toberman et al, 2011).…”

“…Urease activities influence the transformation and fate of applied urea fertilizer. Its activity is influenced by the type and age of plant community (Cao et al, 2014). Suaeda is a perennial, dicotyledonous with high biomass producing plant community and higher enzymatic activities can probably be ascribed to sufficient levels of substrates being available from the root exudates.…”

The structure and soil characteristics of a Pinus tabuliformis planted forest after 60 years of natural development in North China

“…Soil pH was measured with a combination electrode (soil-towater ratio 1:5). The PLFAs were analyzed with a gas chromatograph (Agilent 7890N GC with an Agilent 5975N mass selective detector) as described by Cao et al (2014). Concentrations of each PLFA were standardized relative to 19:0 internal reference concentrations.…”

“…During litter decomposition, a large amount of C is released to the atmosphere in the form of carbon dioxide through microbial respiration, and N acts as an immobilizer due to microorganisms colonization of decaying litter (Chapin et al 2002;Fioretto et al 2005). Plant litter quality is an important influence on soil nutrient cycling, particularly because the C/N ratio, which is the most common index of litter quality, modifies the decomposition rate (Cao et al 2014;Szanser et al 2011;Polyakova and Billor 2007). In the current study, the C, N, and P concentrations of soil in the P. tabuliformis forest were significantly lower than in the Q. mongolica forest likely because the lower C/N ratio in the Q. mongolica forest litter coupled with a higher nutrient concentration improved soil fertility.…”