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Phosphate-solubilizing bacteria (PSB) offer an eco-friendly approach to boost plant growth in soils low or deficient in phosphorus (P). In this study, we isolated 97 PSB strains from the soil around moso bamboo roots in Jiangxi Province, China. The RW37 strain was identified as Enterobacter soli through its physical characteristics and genetic sequencing. Our experiments revealed that RW37 could dissolve phosphate at levels exceeding 400 mg L−1 across a wide range of environmental conditions, including temperature (25–35 °C), pH levels (3.5–7.2), salinities (0–2.0%), and volumes of medium (1/5–3/5 of flask volume), showcasing its adaptability. Furthermore, RW37 showed remarkable phosphate-solubilizing abilities at various pH levels using different phosphate sources, with the highest capacity observed in a medium containing CaHPO4. This study also found a negative correlation between P-solubilizing capacity and fermentation broth pH, indicating that RW37 likely secretes organic acids to dissolve phosphate sources. Pot experiments demonstrated that applying RW37 significantly improved the plant height, biomass, root growth, and P uptake of moso bamboo seedlings in red soil. Our results highlight the potential of RW37 as an eco-friendly biofertilizer for subtropical bamboo forests. [ABSTRACT FROM AUTHOR]

Thinning and understory clearance are among the two most popular forest management practices carried out to improve stand productivity in subtropical plantations. Unfortunately, studies have not fully explored the single and combination effect of thinning and understory clearance on soil microbial properties. By conducting a field manipulation experiment in a subtropical moso bamboo (Phyllostachys edulis) plantation in Southern China, we assessed the effects of thinning, understory clearance, and their combination on soil microbial phospholipid fatty acids (PLFAs) three years after treatments were first applied. We also examined the changes in soil properties after thinning and/or understory clearance. Thinning decreased soil fungal and bacterial PLFAs, and consequently soil total microbial PLFAs due to the increased soil NH4+-N, and NO3−N concentrations. Understory clearance decreased soil pH and soil water content resulting in increased soil fungal PLFAs and the ratio of soil fungal to bacterial (F:B). In addition, thinning and understory clearance caused apparent interactive effects on soil total microbial PLFAs and bacterial PLFAs, and the negative influence of thinning on soil total microbial and bacterial PLFAs were partly compensated by understory clearance. These results suggest the contrasting and interactive effect of thinning and understory clearance should be considered to assess the changes of soil microbial community and ecological processes in subtropical moso bamboo (Phyllostachys edulis) plantations in southern China. [ABSTRACT FROM AUTHOR]

Bark is an essential component of tree branches, yet its role in controlling branch-leached dissolved organic matter (DOM) characteristics remains unknown in forests. Here, we collected branches (about 1.5 cm in diameter) of two evergreen coniferous trees, two deciduous broadleaf trees, and three evergreen broadleaf trees from a subtropical forest in southern China, and subsequently used a bark removal experiment to determine the effects of bark on branch-derived DOM quantity and bioavailability. Regardless of tree type, the presence of bark reduced tree branch-leached dissolved organic carbon (DOC), dissolved total nitrogen (DTN), and dissolved total phosphorus (DTP) productions. Moreover, DOC, DTN, and DTP productions leached from the branches containing bark were always much lower than the expected values summed from barks and the branches without bark. The presence of bark increased DOM aromaticity in the broadleaf tree branch leachates but reduced DOM aromaticity in the coniferous tree branch leachates. During 42 days of incubation, the presence of bark decreased broadleaf tree branch-leached DOM bioavailability and the relative increments of aromaticity, whereas the opposite trends were observed for the coniferous tree branch-leached DOM. Tree branch-derived DOM bioavailability correlated negatively with SUVA254 values, but exhibited no relationship with either DOC:DTN ratio or DOC:DTP ratio. These observations highlight that tree bark can prevent DOM leaching from branches and regulate branch-leached DOM bioavailability via its effect on DOM aromaticity in subtropical forests. [ABSTRACT FROM AUTHOR]

Subtropical plantations have been undergoing understory removal and increased plant litter inputs due to global change and anthropogenic activities. However, how understory removal and increased litter inputs affect litter decomposition is still unclear in these plantations. Using a field manipulation experiment, we assessed the effects of understory removal and litter addition on decomposition rates of leaf litter, twig litter, and mixed leaf and twig litter over 16 months of incubation in a subtropical Chinese fir (Cunninghamia lanceolata) plantation in southern China. We also examined the changes in soil chemical properties and fungal and bacterial phospholipid fatty acids (PLFAs) after understory removal and litter addition. Litter decomposition rates were inhibited by understory removal due to the decreased fungal PLFAs and the associated declines in the ratio of fungal to bacterial biomass. Litter addition also retarded litter decomposition rates, despite the increases in soil NH4+‐N concentration and fungal PLFAs. However, both litter decomposition rates and soil microbial PLFAs remained unchanged in the presence of both understory removal and litter addition. In all treatments, mixed leaf and twig litter produced additive effects on litter decomposition rates. These results suggest that understory removal and litter addition interact to affect litter decomposition dynamics and highlight that litter mixture decomposition rates could be easily predicted from component litter in subtropical Chinese fir plantations of southern China. [ABSTRACT FROM AUTHOR]

Root nutrients are required for the growth and development of roots and shoots, which are closely related to soil quality and fruit productivity. In this study, trees of contrasting stand ages, including young, middle-aged, and old trees, were selected in field sites with common management practices in the navel orange (Citrus sinensis) orchards of Southern China. The fine root N decreased with soil depth and the fine root P was higher of old trees (1.82 g kg-1) than young (1.57 g.kg-1) and middle-aged trees (1.37 g. kg-1). Soil organic C, total N, and P generally increased with plant age in the rhizosphere and bulk soils, while reverse trend was found for sucrase and urease activities. Interestingly, acid phosphatase activity was much higher at a lower depth (202 and 82 g.kg-1 OC d-1 for rhizosphere and bulk soils, respectively) than at an upper depth (46 and 43 g.kg-1 OC d-1 for rhizosphere and bulk soils, respectively). In conclusion, root and soil nutrients generally increased with plant growth. Fine root N decreased while fine root P remained unchanged with soil depth due to the content and rhizosphere effect of index at different soil layers related to N and P, respectively. [ABSTRACT FROM AUTHOR]