[Effects of understory removal on soil microbial community composition in subtropical plantations].

We investigated the effects of understory removal on soil microbial community and soil physicochemical properties in a field experiment following random block design in subtropical moso bamboo () plantations, which were widely contributed in middle subtropical area, aiming to assess the regulation mechanism of understory plants on soil microbial community. The results showed that understory removal significantly increased the contents of soil N, NO-N, and soil available phosphorus, but decreased soil pH and the contents of soil NH-N and soil phosphorus (TP). Moreover, understory removal decreased total and bacterial PLFAs (B) and increasing soil fungal PLFAs (F), resulting in a higher F/B ratio.

Effects of Understory or Overstory Removal on the Abundances of Soil Nematode Genera in a Eucalyptus Plantation.

In south China, eucalyptus plantations typically consist of a single-species overstory (a eucalyptus monoculture) and a dense understory of a dominant fern species. In the current study, we assessed the effects of four treatments [control (CK), understory removal (UR), tree removal (TR), and all-plant removal (PR)] on the abundances of soil nematode genera, which can provide insight into the ecological functions of understory plants and trees. Soil nematodes were sampled six times (once before and five times after treatments were implemented) at 0-5 and 5-10 cm soil depths.

First report of Colletotrichum fioriniae causing anthracnose on mu oil tree in China.

Mu oil tree (Vernicia montana) is an economically important woody oil plant, which is widely distributed in southern China. In mid-May 2020, a leaf spot disease was observed on the leaves of mu oil tree in Taihe County in Jiangxi Province, China (26°55'25.55″N, 114°49'5.

[Difference in intra- and inter-specific competition of two endangered plant species (Toona ciliate var. pubescens and Taxus chinensis var. mairei)in the middle subtropical zone of China].

Endangered plant species are an important part of global biodiversity. To understand the competition patterns and mechanisms of endangered tree species from plant growth forms in the middle subtropical forest ecosystems, we examined the differences in intra- and inter-specific competitions between Toona ciliate var. pubescens (an intolerant of shade, deciduous species) and Taxus chinensis var.

Effects of spent mushroom substrate-derived biochar on soil CO and NO emissions depend on pyrolysis temperature.

Edible mushroom cultivation is an important industry in intensively managed forest understories. However, proper disposal of spent mushroom substrate (SMS) presents a challenge to its sustainable development. Biochar derived from SMS could be used to improve soil quality while providing a solution for SMS disposal.

Isolation and characterization of two phosphate-solubilizing fungi from rhizosphere soil of moso bamboo and their functional capacities when exposed to different phosphorus sources and pH environments.

Phosphate-solubilizing fungi (PSF) generally enhance available phosphorus (P) released from soil, which contributes to plants' P requirement, especially in P-limiting regions. In this study, two PSF, TalA-JX04 and AspN-JX16, were isolated from the rhizosphere soil of moso bamboo (Phyllostachys edulis) widely distributed in P-deficient areas in China and identified as Talaromyces aurantiacus and Aspergillus neoniger, respectively. The two PSF were cultured in potato dextrose liquid medium with six types of initial pH values ranging from 6.

Soil phosphorus functional fractions and tree tissue nutrient concentrations influenced by stand density in subtropical Chinese fir plantation forests.

Stand density regulation is an important measure of plantation forest management, and phosphorus (P) is often the limiting factor of tree productivity, especially in the subtropics and tropics. However, the stand density influence on ecosystem P cycling is unclear in Chinese fir (Cunninghamia lanceolata) plantations of subtropical China. We collected rhizosphere and bulk soils, leaves and twigs with different ages and roots with different orders to measure P and nitrogen (N) variables in Chinese fir plantations with low density (LDCF) and high density (HDCF) at Fujian and Hunan provinces of subtropical China.

Exogenous nutrients and carbon resource change the responses of soil organic matter decomposition and nitrogen immobilization to nitrogen deposition.

It is unclear whether exogenous nutrients and carbon (C) additions alter substrate immobilization to deposited nitrogen (N) during decomposition. In this study, we used laboratory microcosm experiments and (15)N isotope tracer techniques with five different treatments including N addition, N+non-N nutrients addition, N+C addition, N+non-N nutrients+C addition and control, to investigate the coupling effects of non-N nutrients, C addition and N deposition on forest floor decomposition in subtropical China. The results indicated that N deposition inhibited soil organic matter and litter decomposition by 66% and 38%, respectively.

[Variability of soil water soluble organic carbon content and its response to temperature change in green spaces along urban-to-rural gradient of Nanchang, China].

Topsoil of green space including typical forest, shrub and grassland were collected to measure their water soluble organic carbon ( WSOC) before and after incubation of 30 days at 5, 15, 25, 35 and, 45 °C. The results showed the average values of WSOC were higher in urban than in rural green spaces, but the percentage of WSOC to total organic carbon (TOC) showed an opposite trend. No significant changes were found among the three green space types in WSOC and WSOC/TOC.

Invariant community structure of soil bacteria in subtropical coniferous and broadleaved forests.

Soil bacteria may be influenced by vegetation and play important roles in global carbon efflux and nutrient cycling under global changes. Coniferous and broadleaved forests are two phyletically distinct vegetation types. Soil microbial communities in these forests have been extensively investigated but few studies have presented comparable data regarding the characteristics of bacterial communities in subtropical forests.

Topsoil and Deep Soil Organic Carbon Concentration and Stability Vary with Aggregate Size and Vegetation Type in Subtropical China.

The impact of reforestation on soil organic carbon (OC), especially in deep layer, is poorly understood and deep soil OC stabilization in relation with aggregation and vegetation type in afforested area is unknown. Here, we collected topsoil (0-15 cm) and deep soil (30-45 cm) from six paired coniferous forests (CF) and broad-leaved forests (BF) reforested in the early 1990s in subtropical China. Soil aggregates were separated by size by dry sieving and OC stability was measured by closed-jar alkali-absorption in 71 incubation days.

Nitrogen and phosphorus additions alter nutrient dynamics but not resorption efficiencies of Chinese fir leaves and twigs differing in age.

It is unclear how or even if phosphorus (P) input alters the influence of nitrogen (N) deposition in a forest. In theory, nutrients in leaves and twigs differing in age may show different responses to elevated nutrient input. To test this possibility, we selected Chinese fir (Cunninghamia lanceolata) for a series of N and P addition experiments using treatments of +N1 - P (50 kg N ha(-1) year(-1)), +N2 - P (100 kg N ha(-1) year(-1)), -N + P (50 kg P ha(-1) year(-1)), +N1 + P, +N2 + P and -N - P (without N and P addition).

Response of soil respiration and ecosystem carbon budget to vegetation removal in Eucalyptus plantations with contrasting ages.

Reforested plantations have substantial effects on terrestrial carbon cycling due to their large coverage area. Although understory plants are important components of reforested plantations, their effects on ecosystem carbon dynamics remain unclear. This study was designed to investigate the effects of vegetation removal/understory removal and tree girdling on soil respiration and ecosystem carbon dynamics in Eucalyptus plantations of South China with contrasting ages (2 and 24 years old).

Contributions of understory and/or overstory vegetations to soil microbial PLFA and nematode diversities in Eucalyptus monocultures.

Ecological interactions between aboveground and belowground biodiversity have received many attentions in the recent decades. Although soil biodiversity declined with the decrease of plant diversity, many previous studies found plant species identities were more important than plant diversity in controlling soil biodiversity. This study focused on the responses of soil biodiversity to the altering of plant functional groups, namely overstory and understory vegetations, rather than plant diversity gradient.

Asynchronous responses of soil microbial community and understory plant community to simulated nitrogen deposition in a subtropical forest.

Atmospheric nitrogen (N) deposition greatly affects ecosystem processes and properties. However, few studies have simultaneously examined the responses of both the above- and belowground communities to N deposition. Here, we investigated the effects of 8 years of simulated N deposition on soil microbial communities and plant diversity in a subtropical forest.