Effects of returning paddy field to wetland on composition and stability of soil aggregates in the Yellow River Delta.

The composition and stability of soil aggregates are important indicators for measuring soil quality, which would be affected by land use changes. Taking wetlands with different returning years (2 and 15 years) in the Yellow River Delta as the research object, paddy fields and natural wetlands as control, we analyzed the changes in soil physicochemical properties and soil aggregate composition. The results showed that soil water content, total organic carbon, dissolved organic carbon and total phosphorus of the returning soil (0-40 cm) showed an overall increasing trend with returning period, while soil pH and bulk density was in adverse.

[Research progress on Rhododendron molle in treatment of rheumatoid arthritis].

Rheumatoid arthritis(RA), as a chronic autoimmune disease, has a high incidence and disability rate, causing significant suffering to patients. Due to its complex pathogenesis, it has not been fully elucidated to date, and its treatment remains a challenging problem in the medical field. Although western medicine treatment options have certain efficacy, they require prolonged use and are expensive.

[Effects of Water-salt Environment on Freshwater Wetland Soil C, N, and P Ecological Stoichiometric Characteristics in the Yellow River Estuary Wetland].

Carbon (C), nitrogen (N), and phosphorus (P) are important nutrients, and their ecological stoichiometric characteristics can reflect the quality and fertility capacity of soil, which is critical to understanding the stable mechanisms of estuarine wetland ecosystems. Under global changes, the increase in salinity and flooding caused by sea level rise will lead to changes in biogeochemical processes in estuarine wetlands, which is expected to affect the ecological stoichiometric characteristics of soil C, N, and P and ultimately interfere with the stability of wetland ecosystems. However, it remains unclear how the C, N, and P ecological stoichiometric characteristics respond to the water-salt environment in estuarine wetlands.

[Spatial Distribution and Eco-stoichiometric Characteristics of Soil Nutrient Elements Under Different Vegetation Types in the Yellow River Delta Wetland].

To clarify the distribution characteristics and the ecological stoichiometric characteristics of nutrient elements in soils under different vegetation types, four typical natural wetlands, i.e., wetland, wetland, wetland, and wetland, as well as spp.

[C:N:P stoichiometry in plants and soils of wetland under different water-salt habitats].

We examined the effects of channel diversion of Yellow River on the content and stoichiometry of carbon (C), nitrogen (N) and phosphorus (P) in the organs of reeds (stem, leaf, rhizome and fibrous root) and soils in three typical communities in the Yellow River Delta, including community in the former Yellow River course abandoned in 1996, community on the new Yellow River course and the communities on the intertidal area (far from the abandoned and current channel but affected by the tides). The results showed that foliar C, N and P contents of were highest in the communities of abandoned Yellow River course. Leaf N, stem C and rhizome P contents were highest in the communities of new Yellow River course.

[Effect of environmental and biotic factors on net ecosystem CO exchange over a coastal wetland in the Yellow River Delta].

Using the eddy covariance technique, we measured the net ecosystem CO exchange (NEE) and its environmental and biotic factors over a coastal wetland in the Yellow River Delta to investigate the diurnal and seasonal variation in NEE and quantify the effect of environmental and biotic factors on NEE. The results showed that the diurnal change of NEE showed a distinct U-shaped curve during the growing season, but not with substantial variation in its amplitude during the non-growing season. During the growing season, the wetland acted as a significant net sink for CO, while it became carbon source during the non-growing season.

[Net ecosystem CO2 exchange and its environmental regulation mechanisms in a reed wetland in the Yellow River Delta of China during the growth season].

By using eddy covariance technique, this paper measured the net ecosystem CO2 exchange (NEE) in a reed (Phragmites australis) wetland in the Yellow River Delta of China during the growth season of 2011, and investigated the variation patterns of the NEE and related affecting factors. The average diurnal variation of the NEE in different months showed a U-type curve, with the maximum net CO2 uptake rate and release rate being (0.44 +/- 0.

[Distribution characteristics of soil organic carbon and its composition in Suaeda salsa wetland in the Yellow River delta].

Applying the method of physical fractionation, distribution characteristics of soil organic carbon and its composition in Suaeda salsa wetland in the Yellow River delta were studied. The results showed that the heavy fraction organic carbon was the dominant component of soil organic carbon in the studied region. There was a significantly positive relationship between the content of heavy fraction organic carbon, particulate organic carbon and total soil organic carbon.

[Effects of water-salt stresses on seedling growth and activities of antioxidative enzyme of Suaeda salsa in coastal wetlands of the Yellow River Delta].

The halophyte Suaeda salsa is the pioneer plant and is used for the degraded coastal wetland in Yellow River Delta. The water-salt stress is the most important factor for ecological restoration to degraded coastal wetland. To understand the adaptive mechanism of Suaeda salsa to water-salt stresses, the induced effects of different groundwater table depths (0, -10, -20, -30 cm) and salt stress (0%, 1%, 2%, 3%) on seedlings of Suaeda salsa plant were characterized by the growth parameters of plant height, branch number and biomass of different organs and biological indices of leaf chlorophyll content, the activities of SOD, CAT, the leaf content of MDA and protein.

[Evolution process and related driving mechanisms of Yellow River Delta since the diversion of Yellow River].

Based on the 23 sheets of remote sensing images from 1976 to 2009, in combining with the water and sediment data from Lijin station and the annual precipitation data of Yellow River Basin from 1976 to 2008, this paper quantitatively analyzed the features of water and sediment discharge from Yellow River, and the evolution process of Yellow River Delta and related driving mechanisms. In 1976-2008, the annual runoff and the annual sediment discharge into sea changed largely and frequently, but overall, presented a decreasing trend. Since the course of the Yellow River changed its direction to Qingshui channel in 1976, the Delta coastline and area were generally in a silting-up state.

[Spatial distribution characteristics of organic carbon in the soil-plant systems in the Yellow River estuary tidal flat wetland].

Well-understand the organic carbon status in the Yellow River delta is the most important for studying the biogeochemical processes of the muddy-sandy coastal wetland and ecological restoration. The spatial distribution characteristics and its impact factors of organic carbon in the plant-soil systems of new-born tidal flat wetland in the Yellow River estuary were studied. The results showed that the difference of plant organic carbon content in different plant communities were not obvious, however significant difference of the plant organic carbon density was observed.

[Seasonal changes of potassium, calcium and magnesium contents and accumulation in Calamagrostis angustifolia in Sanjiang Plain].

From May to October 2004, the seasonal changes of K, Ca, and Mg contents and accumulation in Calamagrostis angustifolia, the dominant species in the typical meadow and marsh meadow communities of Sanjiang Plain, were studied. There was a greater difference in the seasonal changes of K, Ca, and Mg contents in different parts of typical meadow C. angustifolia (TMC) and marsh meadow C.

[Nitrogen accumulation and allocation in Calamagrostis angusifolia in different plant communities of Sanjiang Plain].

From May to October in 2004, the characteristics of nitrogen (N) accumulation and allocation in Calamagrostis angustifolia, the dominant species in the typical meadow and marsh meadow communities of Sanjiang Plain, were studied. The results showed that the total nitrogen (TN) content in the aboveground organs and litters of typical meadow C. angustifolia (TMC) and marsh meadow C.

Element cycling in the dominant plant community in the Alpine tundra zone of Changbai Mountains, China.

Element cycling in the dominant plant communities including Rh. aureum, Rh. redowskianum and Vaccinium uliginosum in the Alpine tundra zone of Changbai Mountains in northeast China was studied.