Soil microbial biomass, activity and community composition in adjacent native and plantation forests of subtropical Australia   总被引：2，自引：0，他引：2  

Joanne Burton  Chengrong Chen  Zhihong Xu  Hossein Ghadiri 《Journal of Soils and Sediments》2010,10(7):1267-1277

Purpose

Soil nitrogen (N) availability is a critical determinant of plantation productivity in subtropical Australia and is influenced by the soil microbial community. The size, structure and function of the soil microbial community can be impacted by land-use change and residue management. The objectives of this study were to examine the impact of land-use change from (1) native forest (NF) to first rotation (1R) hoop pine plantation and (2) 1R hoop pine plantation to second rotation (2R) hoop pine plantation on the soil microbial community. The impact of residue management on the soil microbial community was also investigated in the 2R forest, where soil microbial parameters were measured in tree rows (2R-T) and windrows (2R-W). In addition, relationships between soil microbial parameters and soil N parameters were investigated.

Materials and methods

Each of the four treatments (NF, 1R, 2R-T and 2R-W) had five 24-m² replicate plots from which 15 soil cores were collected and bulked at three depths (0–10, 10–20, 20–30 cm). Microbial biomass carbon (MBC) and N (MBN) and soil respiration were measured on field moist soils. In addition, carbon (C) source utilisation patterns were assessed using the whole soil MicroResp? technique (Campbell et al. 2003).

Results and discussion

Results indicate that the land-use change from NF to 1R hoop pine plantation significantly reduced MBC, respiration rate, soil total C and total N. Furthermore, the land-use change appeared to have a significant impact on the soil microbial community composition measured using MicroResp? profiles. Land-use change from 1R to 2R hoop pine plantation resulted in a decline in total C and MBN and a shift in microbial community composition. When compared to the 2R-T soils, the 2R-W soils tended to have a greater microbial biomass and respiration rate. Residue management also influenced the microbial community composition measured in the MicroResp? profiles.

Conclusions

Results indicate that land-use change had a significant impact on the soil microbial community, which was likely to be related to shifts in the quality and quantity of organic inputs associated with the change in land use. This may have significant implications for the long-term productivity of the soil resource. Further studies are required to confirm a difference in microbial community composition associated with residue management. In addition, long-term experiments in subtropical Australia are necessary to verify the results of this snapshot study and to improve our understanding of the impact of single-species plantation forestry and residue management on the soil microbial community, soil N dynamics and ultimately the long-term sustainability of the soil resource.  相似文献   

Why seedlings grow: influence of plant attributes     

Steven C. Grossnickle  Joanne E. MacDonald 《New Forests》2018,49(1):1-34

Successful forest restoration requires planting quality seedlings with optimal growth potential. Thus, nurseries need to produce seedlings with plant attributes that favor the best chance of successful establishment once they are field planted. From the mid-twentieth century on, research foresters have critically examined plant attributes that confer improved seedling growth under various restoration site conditions. This review examines the value of commonly measured seedling quality attributes (i.e., height, diameter, root mass, shoot-to-root ratio, drought resistance, freezing tolerance, nutrient status, root growth potential, and root electrolyte leakage) that have been recognized as important in explaining why seedlings with improved attributes have better growth after planting. Seedlings with plant attributes that fall within the appropriate range of values can increase the speed with which they overcome planting stress, initiate growth, and become “coupled” to the forest restoration site, thereby ensuring successful seedling establishment. Although planting high quality seedlings does not guarantee successful seedling establishment, it increases chances for successful establishment and growth.  相似文献   

Signatures of adaptation to obligate biotrophy in the Hyaloperonospora arabidopsidis genome   总被引：2，自引：0，他引：2  

Baxter L  Tripathy S  Ishaque N  Boot N  Cabral A  Kemen E  Thines M  Ah-Fong A  Anderson R  Badejoko W  Bittner-Eddy P  Boore JL  Chibucos MC  Coates M  Dehal P  Delehaunty K  Dong S  Downton P  Dumas B  Fabro G  Fronick C  Fuerstenberg SI  Fulton L  Gaulin E  Govers F  Hughes L  Humphray S  Jiang RH  Judelson H  Kamoun S  Kyung K  Meijer H  Minx P  Morris P  Nelson J  Phuntumart V  Qutob D  Rehmany A  Rougon-Cardoso A  Ryden P  Torto-Alalibo T  Studholme D  Wang Y  Win J  Wood J  Clifton SW  Rogers J  Van den Ackerveken G  Jones JD 《Science (New York, N.Y.)》2010,330(6010):1549-1551

Many oomycete and fungal plant pathogens are obligate biotrophs, which extract nutrients only from living plant tissue and cannot grow apart from their hosts. Although these pathogens cause substantial crop losses, little is known about the molecular basis or evolution of obligate biotrophy. Here, we report the genome sequence of the oomycete Hyaloperonospora arabidopsidis (Hpa), an obligate biotroph and natural pathogen of Arabidopsis thaliana. In comparison with genomes of related, hemibiotrophic Phytophthora species, the Hpa genome exhibits dramatic reductions in genes encoding (i) RXLR effectors and other secreted pathogenicity proteins, (ii) enzymes for assimilation of inorganic nitrogen and sulfur, and (iii) proteins associated with zoospore formation and motility. These attributes comprise a genomic signature of evolution toward obligate biotrophy.  相似文献   

Gender relations in household grain storage management and marketing: the case of Binga District,Zimbabwe     

Joanne Manda  Brighton M. Mvumi 《Agriculture and Human Values》2010,27(1):85-103

This study uses the Locke and Okali gender analysis framework to explore gender relations surrounding grain storage management and marketing in Binga District of Zimbabwe. The study was conducted during one grain storage season and involved multiple visits to selected households, which were used as case studies. The main question that the study sought to address was: “What bargaining goes on between men and women in the area of stored grain management and marketing?” Data were collected from four households, fitting into the following categories: simple monogamous, complex monogamous (two scenarios), and polygamous. Participatory rural appraisal tools and techniques were extensively used and formed the backdrop of all the data collection. The study established that much bargaining and strategizing occurs within the household in order for women to exercise control over the use of stored grain. The bargaining process was found to be a complex one of give-and-take without an immediately recognizable winner. There is evidence that women use this bargaining power to exert influence on their relative position in the household in terms of independent income generation and management, seniority, and overall household food security policies. While bargaining between and within gender remains shrouded in subtleness, individuals in a household consciously use their skills to manipulate the situation to their best advantage. This article is expected to initiate broader debate in the area of gender roles and bargaining in grain post-harvest management, an area often kept private by smallholder farmers in sub-Saharan Africa.  相似文献   

饮奶——强健您的骨骼     

Joanne Todd 《中国乳业》2010,(8):76-77

或许您听说过,随着年龄的增长,骨质疏松在所难免。但这种说法其实是一种误解。我们可以通过多种方法改善骨骼健康状况,最终提高生活质量。  相似文献   

Strong resistance to phosphine in the rusty grain beetle,Cryptolestes ferrugineus (Stephens) (Coleoptera: Laemophloeidae): its characterisation,a rapid assay for diagnosis and its distribution in Australia     

Manoj K Nayak  Joanne C Holloway  Robert N Emery  Hervoika Pavic  Justin Bartlet  Patrick J Collins 《Pest management science》2013,69(1):48-53

BACKGROUND: The recent development of very high resistance to phosphine in rusty grain beetle, Cryptolestes ferrugineus (Stephens), seriously threatens stored‐grain biosecurity. The aim was to characterise this resistance, to develop a rapid bioassay for its diagnosis to support pest management and to document the distribution of resistance in Australia in 2007–2011. RESULTS: Bioassays of purified laboratory reference strains and field‐collected samples revealed three phenotypes: susceptible, weakly resistant and strongly resistant. With resistance factors of > 1000 × , resistance to phosphine expressed by the strong resistance phenotype was higher than reported for any stored‐product insect species. The new time‐to‐knockdown assay rapidly and accurately diagnosed each resistance phenotype within 6 h. Although less frequent in western Australia, weak resistance was detected throughout all grain production regions. Strong resistance occurred predominantly in central storages in eastern Australia. CONCLUSION: Resistance to phosphine in the rusty grain beetle is expressed through two identifiable phenotypes: weak and strong. Strong resistance requires urgent changes to current fumigation dosages. The development of a rapid assay for diagnosis of resistance enables the provision of same‐day advice to expedite resistance management decisions. © 2012 Commonwealth of Australia. Published by John Wiley & Sons, Ltd.  相似文献   

Utility of endoscopic biopsies of the duodenum and ileum for diagnosis of inflammatory bowel disease and small cell lymphoma in cats     

Scott KD  Zoran DL  Mansell J  Norby B  Willard MD 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2011,25(6):1253-1257

  相似文献   

Association of histologic tumor characteristics and size of surgical margins with clinical outcome after surgical removal of cutaneous mast cell tumors in dogs     

Schultheiss PC  Gardiner DW  Rao S  Olea-Popelka F  Tuohy JL 《Journal of the American Veterinary Medical Association》2011,238(11):1464-1469

  相似文献   

Correlating Clinical Activity and Histopathologic Assessment of Gastrointestinal Lesion Severity: Current Challenges     

Michael Willard  Joanne Mansell 《Veterinary Clinics of North America: Small Animal Practice》2011,41(2):457-463

  相似文献   

Advances in remote sensing of freshwater fish habitat: A systematic review to identify current approaches,strengths and challenges     

Spencer Dakin Kuiper  Nicholas C. Coops  Scott G. Hinch  Joanne C. White 《Fish and Fisheries》2023,24(5):829-847

Remote sensing technology offers the ability to derive information on freshwater fish habitats across broad geographic areas and has the potential to transform approaches to monitoring. However, the numerous platforms, sensors and analytical software that are available may overwhelm those interested in utilizing this important technology and thus limit its broad application and uptake. Our review is intended to shed light on the capacity of this technology to transform freshwater fish habitat monitoring by examining the fundamental characteristics of the major remote sensing technologies that have been used for characterizing freshwater habitats, conducting a systematic literature review of studies that have used remote sensing technologies to characterize freshwater fish habitats and, highlighting some of the key habitat features, fish species and regions, that have been examined. Lastly, we identify the relative strengths and weaknesses of the various remote sensing technologies that can be used, recommend future research that could help improve the use of these technologies, and, provide a series of important considerations for those who are interested in utilizing these technologies for freshwater fish habitat characterization.  相似文献