Phosphorus limitation induced by nitrogen addition changed soil microbial community structure in a subtropical forest.

Soil microorganisms play an important role in the biogeochemical cycles of terrestrial ecosystems. How-ever, it is still unclear how the amount and duration of nitrogen (N) addition affect soil microbial community structure and whether there is a correlation between the changes in microbial community structure and their nutrient limi-tation status. In this study, we conducted an N addition experiment in a subtropical forest to simulate N deposition with three treatments: control (CK, 0 kg N·hm·a), low N (LN, 40 kg N·hm·a), and high N (HN, 80 kg N·hm·a).

[Effects of different carbon addition modes on the soil priming effect of a subtropical forest under nitrogen deposition].

Priming effect (PE) plays an important role in regulating terrestrial soil carbon (C) cycling, but the impact of different C addition modes on the PE in subtropical forest ecosystems with increasing nitrogen (N) deposition is unclear. In this study, we investigated the effects of C addition patterns (single or repeated C addition) on soil PE by adding C-labeled glucose for 90 d in an incubation experiment with different levels of N application (0, 20, and 80 kg N·hm·a). The different patterns of glucose addition significantly increased soil organic C (SOC) mineralization and produced positive PE.

[Responses of soil microbial carbon use efficiency to short-term nitrogen addition in forest].

As an important parameter regulating soil carbon mineralization, microbial carbon use efficiency (CUE) is essential for the understanding of carbon (C) cycle in terrestrial ecosystems. Three nitrogen supplemental levels, including control (0 kg N·hm·a), low nitrogen (40 kg N·hm·a), and high nitrogen (80 kg N·hm·a), were set up in a forest in the Daiyun Mountain. The basic physical and chemical properties, organic carbon fractions, microbial biomass, and enzyme activities of the soil surface layer (0-10 cm) were measured.

[Effects of nitrogen addition on the kinetic parameters of soil acid phosphomonoesterase in a Moso bamboo forest].

Soil phosphatases are important in the mineralization of organophosphates and in the phosphorus (P) cycle. The kinetic mechanisms of phosphatases in response to nitrogen (N) deposition remain unclear. We carried out a field experiment with four different concentrations of N: 0 g N·hm·a(control), 20 g N·hm·a(low N), 40 g N·hm·a(medium N), and 80 g N·hm·a(high N) in a subtropical Moso bamboo forest.

Enzyme stoichiometry evidence revealed that five years nitrogen addition exacerbated the carbon and phosphorus limitation of soil microorganisms in a forest.

The activity and stoichiometry of soil extracellular enzyme can provide a good indication for changes in soil nutrient availability and microbial demands for nutrients. However, it remains unclear how would nitrogen (N) deposition affect nutrient limitation of microbes in subtropical forest soils. We conducted a 5 years N addition experiment in a subtropical forest.

Removal of heavy metals from contaminated paddy soils using chemical reductants coupled with dissolved organic carbon solutions.

General acid washing is commonly used to treat heavy metal-contaminated soils, but it is sometimes difficult to achieve remediation aims in severely polluted soils. If we expose the surfaces of Fe oxide minerals to reductive dissolution during washing treatment, more of the metals initially adsorbed to these surfaces will be liberated, which may encourage the removal of heavy metals. Initially, the metal extraction capabilities of nine chemical reductants were compared in ten soil samples polluted by Cr, Cu, Zn, and Ni.

[Responses of soil phosphorus fractions and microorganisms to nitrogen application in a subtropical Phyllostachys pubescen forest].

Phosphorus (P) is an important nutrient for plant and microbial growth. Soil P availabi-lity is poor in subtropical areas. Long-term heavy nitrogen (N) deposition might further reduce P availability.

[Effects of nitrogen deposition on the concentration and spectral characteristics of dissolved organic matter in soil in Moso bamboo plantations.].

The subtropical zone in China is one of the regions most affected by nitrogen deposition. Soil dissolved organic matter (DOM) is considered to be an important indicator of soil organic matter. Nitrogen deposition may alter the quality and quantity of soil DOM by changing soil microbial activity.

[Effects of precipitation reduction on the composition and stability of soil organic matter in a young Cunninghamia lanceolata plantation.].

It is hard to predict the response of soil organic matter (SOM) to global climate change due to its heterogenous chemical structure. With the development of molecular techniques to identify the structure, sources and stages of SOM degradation, long-standing questions regarding the composition and stability of SOM might be resolved. To investigate the effects of changes in precipitation patterns on the stability of SOM, we analyzed the specific compositions and extent of degradation of SOM using biomarkers, in a young Cunninghamia lanceolata plantation after reducing 50% of precipitation (P) for two years.

[Characteristics of soil phosphorus fractions of different vegetation types in subtropical forests and their driving factors.].

Soil P fraction, microbial biomass P (MBP), and activities of acid phosphomonoesterase (ACP) and phosphodiesterase (PD) were analyzed under evergreen broad-leaved forest, mixed forest and coniferous forest in Daiyun Mountains. The results showed that labile-P comprised only 1.0%-4.

[Effects of nitrogen deposition on diversity and composition of soil bacterial community in a subtropical Cunninghamia lanceolata plantation.].

The increasing rate of atmospheric nitrogen (N) deposition has become the focus of research attention. Soil bacterial community plays an important role in soil nutrient cycling. We stimulated N deposition at the Forest Ecosystem of Fujian Normal University and Global Change Research Station in Chenda Town, Sanming City in the Fujian Province of China.

Kinetic and thermodynamic studies on removal of Cu(II) from aqueous solutions using soil nanoclays.

Soil clays (< 2,000 nm) (SC) and soil nanoclays (< 100 nm) (SNC) were used as adsorbents for removal of Cu(II) from aqueous solution. The experiments were conducted with variables including pH, interaction time, concentration of Cu(II) and temperature. Four kinetic models have been employed to investigate adsorption mechanisms, and the experimental data more closely resemble a second-order process of the kinetic model.

Some selected heavy metal concentrations in water, sediment, and oysters in the Er-Ren estuary, Taiwan: chemical fractions and the implications for biomonitoring.

Studies of heavy metal contamination and ecological risk in estuaries are an important emerging area of environmental science. However, there have been few detailed studies of heavy metal contamination that concern the spatial variation of heavy metal levels in water, sediment, and oyster tissue. Because of the effective uptake of heavy metals, cultured oysters are a cheap and effective subject for study.