188 research outputs found

    Spatial distribution of carbon dynamics and nutrient enrichment capacity in different layers and tree tissues of Castanopsis eyeri natural forest ecosystem

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    Forest ecosystem carbon (C) storage primarily includes vegetation layers C storage, litter C storage, and soil C storage. The precise assessment of forest ecosystem C storage is a major concern that has drawn widespread attention in global climate change worldwide. This study explored the C storage of different layers of the forest ecosystem and the nutrient enrichment capacity of the vegetation layer to the soil in the Castanopsis eyeri natural forest ecosystem (CEF) present in the northeastern Hunan province, central China. The direct field measurements were used for the estimations. Results illustrate that trunk biomass distribution was 48.42% and 62.32% in younger and over-mature trees, respectively. The combined biomass of the understory shrub, herb, and litter layers was 10.46 t·hm−2, accounting for only 2.72% of the total forest biomass. On average, C content increased with the tree age increment. The C content of tree, shrub, and herb layers was 45.68%, 43.08%, and 35.76%, respectively. Litter C content was higher in the undecomposed litter (44.07 %). Soil C content continually decreased as the soil depth increased, and almost half of soil C was stored in the upper soil layer. Total C stored in CEF was 329.70 t·hm−2 and it follows the order: tree layer > soil layer > litter layer > shrub layer > herb layer, with C storage distribution of 51.07%, 47.80%, 0.78%, 0.25%, and 0.10%, respectively. Macronutrient enrichment capacity from vegetation layers to soil was highest in the herb layer and lowest in the tree layer, whereas no consistent patterns were observed for trace elements. This study will help understand the production mechanism and ecological process of the C. eyeri natural forest ecosystem and provide the basics for future research on climate mitigation, nutrient cycling, and energy exchange in developing and utilizing sub-tropical vegetationThis research was financially supported by research funding from Central South University of Forestry and Technology and the Hunan province finance department (No.70702-45200003

    Intercropping of peanut–tea enhances soil enzymatic activity and soil nutrient status at different soil profiles in Subtropical Southern China

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    Intercropping is one of the most widely used agroforestry techniques, reducing the harmfulimpacts of external inputs such as fertilizers. It also controls soil erosion, increases soil nutrientsavailability, and reduces weed growth. In this study, the intercropping of peanut (ArachishypogaeaL.)was done with tea plants (Camellia oleifera), and it was compared with the mono-cropping of tea andpeanut. Soil health and fertility were examined by analyzing the variability in soil enzymatic activityand soil nutrients availability at different soil depths (0–10 cm, 10–20 cm, 20–30 cm, and 30–40 cm).Results showed that the peanut–tea intercropping considerably impacted the soil organic carbon(SOC), soil nutrient availability, and soil enzymatic responses at different soil depths. The activityof protease, sucrase, and acid phosphatase was higher in intercropping, while the activity of ureaseand catalase was higher in peanut monoculture. In intercropping, total phosphorus (TP) was 14.2%,34.2%, 77.7%, 61.9%; total potassium (TK) was 13.4%, 20%, 27.4%, 20%; available phosphorus (AP)was 52.9%, 26.56%, 61.1%; 146.15% and available potassium (AK) was 11.1%, 43.06%, 46.79% higherthan the mono-cropping of tea in respective soil layers. Additionally, available nitrogen (AN) was51.78%, 5.92%, and 15.32% lower in the 10–20 cm, 20–30 cm, and 30–40 cm layers of the intercroppingsystem than in the mono-cropping system of peanut. Moreover, the soil enzymatic activity wassignificantly correlated with SOC and total nitrogen (TN) content across all soil depths and croppingsystems. The depth and path analysis effect revealed that SOC directly affected sucrase, protease,urease, and catalase enzymes in an intercropping system. It was concluded that an increase in the soilenzymatic activity in the intercropping pattern improved the reaction rate at which organic matterdecomposed and released nutrients into the soil environment. Enzyme activity in the decompositionprocess plays a vital role in forest soil morphology and function. For efficient land use in the croppingsystem, it is necessary to develop coherent agroforestry practices. The results in this study revealedthat intercropping certainly enhance soil nutrients status and positively impacts soil conservation.The funding sources include the National Science and Technology Support Grant ofChina (2015BAD07B0503), Forestry Science and Technology Promotion Project of China (No. 122017) and Postdoctoral research funding of Central South University of Forestry and Technology(70702-45200003)

    Unraveling the Influence of Land-Use Change on δ 13C, δ 15N, and Soil Nutritional Status in Coniferous, Broadleaved, and Mixed Forests in Southern China: A Field Investigation

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    Natural isotopic abundance in soil and foliar can provide integrated information related to the long-term alterations of carbon (C) and nitrogen (N) cycles in forest ecosystems. We evaluated total carbon (TC), total nitrogen (TN), and isotopic natural abundance of C (δ 13C) and N (δ 15N) in soil and foliar of coniferous plantation (CPF), natural broadleaved forest (NBF), and mixed forest stands at three different soil depths (i.e., 0–10, 10–20, and 20–40 cm). This study also explored how soil available nutrients are affected by different forest types. Lutou forest research station, located in Hunan Province, central China, was used as the study area. Results demonstrated that the topsoil layer had higher TC and TN content in the mixed forest stand, resulting in a better quality of organic materials in the topsoil layer in the mixed forest than NBF and CPF. In general, soil TC, TN, and δ 15N varied significantly in different soil depths and forest types. However, the forest type did not exhibit any significant effect on δ 13C. Overall, soil δ 13C was significantly enriched in CPF, and δ 15N values were enriched in mixed forest. Foliar C content varied significantly among forest types, whereas foliar N content was not significantly different. No big differences were observed for foliar δ 15N and δ 13C across forest types. However, foliar δ 13C and δ 15N were positively related to soil δ 13C and δ 15N, respectively. Foliar N, soil and foliar C:N ratio, soil moisture content (SMC), and forest type were observed as the major influential factors affecting isotopic natural abundance, whereas soil pH was not significantly correlated. In addition, forest type change and soil depth increment had a significant effect on soil nutrient availability. In general, soil nutrient availability was higher in mixed forest. Our findings implied that forest type and soil depth alter TC, TN, and soil δ 15N, whereas δ 13C was only driven by soil depth. Moreover, plantations led to a decline in soil available nutrient content compared with NBF and mixed forest stand

    The relationship between modified Graeb score and intraventricular hematoma volume with Glasgow outcome scale and modified Rankin scale in intraventricular hemorrhage of brain: a comparative study

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    Background: Intraventricular hemorrhage (IVH) is an acute neurosurgical condition. The aim of this study was to identify the relationship between modified Graeb score (mGS) and intraventricular hematoma volume with Glasgow outcome scale (GOS) and modified Rankin scale (mRS).Methods: This is a Quasi-experimental study conducted in the department of neurosurgery, Chittagong Medical College Hospital, Chittagong, Bangladesh during the period from 24 July 2018 to 23 July 2019. After a detailed history and clinical examination, 150 patients were selected for this study. The study participants were divided into two major groups- external ventricular drainage (EVD) and conservative; both groups consisted of 44 patients. Written informed consent were taken from the participants. Data were analyzed using statistical package for the social sciences (SPSS) software.Results: Overall mean age was around 60 years with an age range from 15-85 years. More than three fourth of the patients in both groups were from the age group of >50 years (73.83%). There were no differences between EVD and conservative groups regarding medical comorbidities. Most prevalent comorbidity among the patients of both groups’ hypertension, followed by diabetes and previous ischemic stroke. Overall the most frequent symptoms in the studied patients were vomiting, followed by loss of consciousness, headache and convulsion. There were no significant differences between the two groups regarding presenting symptoms. The mean Glasgow coma scale (GCS) score level was significantly lower in the patients with EVD than their counterpart from 1st post-operative day to 8th post-operative day. However, within-group comparison shows that the GCS score was significantly increased from 1st day to 8th day in both groups of patients.Conclusions: These findings can be used to identify patients in whom an EVD may provide measurable outcomes benefit with respect to patient mortality and help guide neurosurgical decision-making in particular patient subgroups with acute IVH

    Perspectives of plantation forests in the sustainable forest development of China

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    Modern forestry is gradually moving towards man-made forests on a large scale. Plantations with advanced forestry system have been introduced with the goal of sustainable forestry development and to enhance social, ecological, and economic benefits. Forest plantations with native and exotic species have been established in China and worldwide with shorter rotation cycles than natural forests. In this paper, we discuss the role and perspectives of plantation forests in the Chinese sustainable forest development, the evolution of various plantation programs, the ecological effects of plantations, and the measures to improve plantation forestry. The Chinese government has given substantial importance to nurturing plantation forest resources through various large scale afforestation programs. In 2019, the total area covered by plantations in China reached 79.54 million ha, with a stock volume of 3.39 billion m³ (59.30 m³ per ha); coniferous forests (26.11 million ha, 32.83%) and broad-leaved forests (26.45 million ha, 33.25%) are the dominant types. Plantations have been primarily distributed in the central and southern parts of the country. Plantations with fast-growing and high-yielding tree species facilitated Chinese afforestation activities and improved the administration of forest production, which effectively boosted the forest industry. Plantation forest resources offer many potential productive, economic, and social advantages, though they are also associated with a loss of biodiversity and climate change makes them likely susceptible to disease and insect attack. Appropriate forest management practices during planning, execution, and maintenance of plantations can contribute to the conservation, promotion, and restoration of biodiversity, with the final aim of attaining a balance between having forest plantations and natural forests.We thank the great help from two anonymous reviews. We also thank our friend Chris Ijeoma for the grammar checking of the manuscript. The funding sources included the Postdoctoral research funding of Central South University of Forestry and Technology, Changsha, China (70702-4520 0003

    Evaluation of humoral immunity and protective efficacy of biofilm producing Staphylococcus aureus bacterin-toxoid prepared from a bovine mastitis isolate in rabbit

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    Mastitis is a one of the major diseases of dairy animals. Staphylococcus aureus is the most common microorganism associated with this dairy scourge. Cure rates of mastitis associated with this pathogen are appallingly low. Biofilm is an important virulence factor and immunogenic structure of S. aureus that makes it resistant to phagocytosis and antibiotics. Reports on the efficacy of vaccine prepared from a biofilm producing S. aureus are infrequent. The present study was designed to evaluate the role of a bacterin-toxoid prepared from a strong biofilm producing S. aureus in effective immunization of rabbits. The strong biofilm producing S. aureus selected from 64 isolates of staphylococci was used to prepare bacterin-toxoid and aluminum hydroxide gel was added as an adjuvant. The vaccine was evaluated in rabbits by challenge protection assay and humoral immune response. The mortality rates in control and vaccinated groups were 80% and 10% at day 7 post challenge and 100% and 20% at day 15 post challenge, respectively. Serum antibody titer (GMT) was significantly higher (294.0) in vaccinated group as compared to control group of rabbits (2.63) at day 45. The results showed that the vaccine has significantly elicited humoral immune response in rabbit and developed protective efficacy against new infections
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