Does Forest Soil Fungal Community Respond to Short-Term Simulated Nitrogen Deposition in Different Forests in Eastern China?

Nitrogen (N) deposition has changed plants and soil microbes remarkably, which deeply alters the structures and functions of terrestrial ecosystems. However, how forest fungal diversity, community compositions, and their potential functions respond to N deposition is still lacking in exploration at a large scale. In this study, we conducted a short-term (4-5 years) experiment of artificial N addition to simulated N deposition in five typical forest ecosystems across eastern China, which includes tropical montane rainforest, subtropical evergreen broadleaved forest, temperate deciduous broadleaved forest, temperate broadleaved and conifer mixed forest, and boreal forest along a latitudinal gradient from tropical to cold temperature zones.

High-level nitrogen additions accelerate soil respiration reduction over time in a boreal forest.

Increased nitrogen (N) inputs are widely recognised to reduce soil respiration (Rs), but how N deposition affects the temporal dynamics of Rs remains unclear. Using a decade-long fertilisation experiment in a boreal larch forest (Larix gmelini) in northeast China, we found that the effects of N additions on Rs showed a temporal shift from a positive effect in the short-term (increased by 8% on average in the first year) to a negative effect over the longer term (decreased by 21% on average in the 11th year). The rates of decrease in Rs for the higher N levels were almost twice as high as those of the low N level.

Yield and quality properties of silage maize and their influencing factors in China.

Silage maize (Zea mays L.) is one of the most important forages in the world, and its yield and quality properties are critical parameters for livestock production and assessment of forage values. However, relationships between its yield and quality properties and the controlling factors are not well documented.

Nonlinear responses of ecosystem carbon fluxes to nitrogen deposition in an old-growth boreal forest.

Nitrogen (N) deposition is known to increase carbon (C) sequestration in N-limited boreal forests. However, the long-term effects of N deposition on ecosystem carbon fluxes have been rarely investigated in old-growth boreal forests. Here we show that decade-long experimental N additions significantly stimulated net primary production (NPP) but the effect decreased with increasing N loads.

Clinical Analysis of Magnetic Nanoparticle Contrast Agent in the Diagnosis of Occult Fracture by Multislice Spiral CT and MRI.

To investigate the differences in the diagnosis and treatment of occult fractures between multi-slice spiral CT (CT) and magnetic resonance imaging (MRI) using I/Fe₃O₄ nanometer contrast agent. This retrospective study analyzed the clinical data of 60 patients with occult fractures and compared the diagnosis results of multislice CT (observation group) and MRI (control group). All the contrast agents used were I/Fe₃O₄ nanometer contrast agents.

Long term effect of nitrogen addition on understory community in a Chinese boreal forest.

Increasing atmospheric nitrogen (N) deposition is an important driver of biodiversity change. By conducting an eight-year N addition experiment (0, 20, 50 and 100 kg N ha yr), we investigated the long-term effect of simulated N deposition on understory species composition and richness in a boreal forest, northeast China. We found that moss cover decreased significantly with increasing N addition.

Responses of forest ecosystems to increasing N deposition in China: A critical review.

China has been experiencing a rapid increase in nitrogen (N) deposition due to intensified anthropogenic N emissions since the late 1970s. By synthesizing experimental and observational data taken from literature, we reviewed the responses of China's forests to increasing N deposition over time, with a focus on soil biogeochemical properties and acidification, plant nutrient stoichiometry, understory biodiversity, forest growth, and carbon (C) sequestration. Nitrogen deposition generally increased soil N availability and soil N leaching and decreased soil pH in China's forests.

The response of tree growth to nitrogen and phosphorus additions in a tropical montane rainforest.

Rapid increase of global nitrogen (N) deposition has greatly altered carbon cycles and functioning of forest ecosystems. Previous studies have focused on changes in carbon dynamics of temperate and subtropical forests through N enrichment experiments; however, the effects of N deposition on tree growth remain inconsistent, especially in tropical forests. Here, we conducted a five-year N addition experiment (0 and 50kgNhayr) in a tropical montane rain forest in Hainan Island, China, to explore the effects of enhanced N deposition on growth of trees.

Effects of nitrogen deposition on soil microbial communities in temperate and subtropical forests in China.

Increasing nitrogen (N) deposition has aroused large concerns because of its potential negative effects on forest ecosystems. Although microorganisms play a vital role in ecosystem carbon (C) and nutrient cycling, the effect of N deposition on soil microbiota still remains unclear. In this study, we investigated the responses of microbial biomass C (MBC) and N (MBN) and microbial community composition to 4-5years of experimentally simulated N deposition in temperate needle-leaf forests and subtropical evergreen broadleaf forests in eastern China, using chloroform fumigation extraction and phospholipid fatty acid (PLFA) methods.

Nitrogen deposition has minor effect on soil extracellular enzyme activities in six Chinese forests.

Soil extracellular enzymes play a key role in mediating a range of forest ecosystem functions (i.e., carbon and nutrients cycling and biological productivity), particularly in the face of atmospheric N deposition that has been increasing at an unprecedented rate globally.