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1.
Bautista Inmaculada Lidón Antonio Lull Cristina González-Sanchis María del Campo Antonio D. 《European Journal of Forest Research》2021,140(6):1469-1485
The effects of a thinning treatment on soil respiration (Rs) were analysed in two dryland forest types with a Mediterranean climate in east Spain: a dry subhumid holm oak forest (Quercus ilex subsp. ballota) in La Hunde; a semiarid postfire regenerated Aleppo pine (Pinus halepensis) forest in Sierra Calderona. Two twin plots were established at each site: one was thinned and the other was the control. Rs, soil humidity and temperature were measured regularly in the field at nine points per plot distributed into three blocks along the slope for 3 years at HU and for 2 years at CA after forest treatment. Soil heterotrophic activity was measured in laboratory on soil samples obtained bimonthly from December 2012 to June 2013 at the HU site. Seasonal Rs distribution gave low values in winter, began to increase in spring before lowering as soil dried in summer. This scenario indicates that with a semiarid climate, soil respiration is controlled by both soil humidity and soil temperature. Throughout the study period, the mean Rs value in the HU C plot was 13% higher than at HU T, and was 26% higher at CA C than the corresponding CA T plot value, being the differences significantly higher in control plots during active growing periods. Soil microclimatic variables explain the biggest proportion of variability for Rs: soil temperature explained 24.1% of total variability for Rs in the dry subhumid forest; soil humidity accounted for 24.6% of total variability for Rs in the semiarid forest. As Mediterranean climates are characterised by wide interannual variability, Rs showed considerable variability over the years, which can mask the effect caused by thinning treatment.
相似文献2.
Silke Ruppel Vigdis Torsvik Frida Lise Daae Lise Øvreås Jörg Rühlmann 《Biology and Fertility of Soils》2007,43(4):449-459
In this study, the interrelation between nitrogen availability and prokaryotic diversity are studied using a well-characterised
system from a long-term field experiment on a loamy sandy soil. The prokaryotic potential functional diversity and community
composition were assessed using community-level physiological profiling (CLPP), and their phylogenetic diversity was analysed
using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) in combination with sequencing analysis.
Highest prokaryotic potential functional diversity was measured in the control soil receiving no N fertilisation, indicating
an efficient as well as versatile utilisation of the substrates in this soil. Both substrate utilisation richness and substrate
utilisation evenness, the two constituents of the functional diversity, were decreased with increasing N supply. Furthermore,
distinct prokaryotic community compositions were generated in N-enriched soils compared to unfertilised control soils. These
differences suggest a dominance of populations adapted to utilising readily available substrates. We demonstrated that the
shift in prokaryotic functional diversity was connected to a shift in the phylogenetic structure of the bacterial and archaeal
communities. Taken together, our data clearly show that, for the sandy soil system, prokaryotic diversity and N availability
were interrelated. 相似文献
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M.?Gutiérrez López M.?Ramajo Matesanz J.?B.?Jesús Lidón D.?J.?Díaz CosínEmail author 《Biology and Fertility of Soils》2003,37(4):231-236
This microcosm study investigated the effect of Hormogaster elisae on the abundance of soil Collembola and Acari in laboratory cultures. Two types of microcosm were prepared: type I consisted of plastic boxes with a 2-mm mesh cage containing two H. elisae, and type II consisted of plastic boxes without a cage. The respective controls contained no earthworms. All of them were kept at 18°C and 20% moisture for 21 days. After this period of time the microcosms were tested and microarthropods were extracted, identified and counted. In general, more microarthropods were recovered from the soils without earthworms. There were significant differences between the soils with respect to the abundance of Collembola (Isotomidae and Sminthuridae), and Acari (Gamasida and Oribatida). The results suggest that, under the experimental conditions employed, H. elisae reduces the abundance of these groups of microarthropods. This may be due to several reasons. A change in environmental heterogeneity produced by H. elisae is suggested. A possible interspecific relationship between these two groups due to competition or depredation is also discussed. 相似文献
4.
J. M. Lynch A. Benedetti H. Insam M. P. Nuti K. Smalla V. Torsvik P. Nannipieri 《Biology and Fertility of Soils》2004,40(6):363-385
This review mainly discusses three related topics: the application of ecological theories to soil, the measurement of microbial diversity by molecular techniques and the impact of transgenic plants and microorganisms on genetic diversity of soil. These topics were debated at the Meeting on Soil Emergency held in Erice (Trapani, Italy) in 2001 for the celebration of the 50th anniversary of the Italian Society of Soil Science. Ecological theories have been developed by studying aboveground ecosystems but have neglected the belowground systems, despite the importance of the latter to the global nutrient cycling and to the presence of life on the Earth. Microbial diversity within the soil is crucial to many functions but it has been difficult in the past to determine the major components. Traditional methods of analysis are useful but with the use of molecular methods it is now possible to detect both culturable and unculturable microbial species. Despite these advances, the link between microbial diversity and soil functions is still a major challenge. Generally studies on genetically modified bacteria have not addressed directly the issue of microbial diversity, being mainly focused on their persistence in the environment, colonization ability in the rhizosphere, and survival. Concerns have been raised that transgenic plants might affect microbial communities in addition to environmental factors related to agricultural practice, season, field site and year. Transgenic plant DNA originating from senescent or degraded plant material or pollen has been shown to persist in soil. Horizontal transfer of transgenic plant DNA to bacteria has been shown by the restoration of deleted antibiotic resistance genes under laboratory in filter transformations, in sterile soil or in planta. However, the transformation frequencies under field conditions are supposed to be very low. It is important to underline that the public debate about antibiotic resistant genes in transgenic plants should not divert the attention from the real causes of bacterial resistance to antibiotics, such as the continued abuse and overuse of antibiotics prescribed by physicians and in animal husbandry. 相似文献
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In contrast with macroorganisms, whose geographical ranges are typically restricted, many microbial species appear to have cosmopolitan distributions. This observation has been explained as a consequence of ubiquitous dispersal caused by the enormous population sizes of microbial species. Recently, this "everything is everywhere, but, the environment selects" theory has been challenged by the detection of considerable regional genetic variability within microbial morphospecies. We demonstrate that, contrary to what is expected under ubiquitous dispersal, evidence of regional-scale metacommunity processes can be detected in microbial morphospecies. Our results imply that the microbial and macrobial world are structured by analogous processes. 相似文献
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Torsvik TH 《Science (New York, N.Y.)》2003,300(5624):1379-1381
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The Totonac homegarden is a traditionally designed agroecosystem mixing different elements, such as cultivated and wild plants, and livestock. Our objective was to understand the role and importance of homegardens as a strategy for subsistence and natural resources management. Anthropological fieldwork was carried out in Coxquihui, Veracruz, Mexico, a Totonac community. Conventional sampling using a questionnaire yielded a sample of 40 individuals, each representing a family group. Personal interviews, life stories, observations, and field transects enriched survey information. Fieldwork permitted identification of four types of Totonac homegardens: backyards, cropping fields, acahuales or fallow fields, and fences or field edges. Each of these gardens yields an array of products and services important for several cultural roles and natural resource management aims. Totonacs see land as the dominant and most critical resource. A great deal of terrain is steeply sloped and soils are poor. Homegardens play a key role in a production system that minimizes these site limitations, striking a balance between resource maintenance and subsistence needs. Their functions are ecological, to foster a multistrata vegetation cover, and a continuous supply of organic matter to the soil; economic, serving as living storehouses where diverse products (food, timber, firewood, forage, animals, ceremonial supplies, medicinal products), are kept through the annual cycle; and social, performing various social roles such as growing medicinal, ritual, and edible plants, thus supporting beliefs and culture continuity. Studies like this contribute to a better understanding of Totonac culture and native ecology, and give ideas for a better land management. 相似文献
10.
为探究磷酸盐在不同水分条件下对土壤铅(Pb)、镉(Cd)的钝化效果及其在酸雨淋溶下修复时可能造成的重金属淋失风险,选择安徽铜陵某矿区周边Cd、Pb污染水稻土为研究对象,对比磷酸氢二铵(DAP)和磷酸三钙(TCP)在不同用量及不同土壤含水率下对Cd、Pb的修复效果,并探讨模拟酸雨条件下含磷钝化剂施用后对Cd、Pb修复稳定性的影响。结果表明:施用两种磷肥均能降低土壤中有效态Cd、Pb含量,DAP使土壤有效态Cd含量降低了41.87%～65.62%,有效态Pb含量降低了38.83%～76.98%;TCP处理下有效态Cd、Pb含量分别降低了39.55%～56.17%、37.52%～66.46%。75%最大田间持水量下有效态Cd含量分别下降了21.22%(TCP)、23.45%(DAP),有效态Pb含量分别下降了14.22%(TCP)、9.28%(DAP)。磷肥对Cd、Pb的固定作用随着酸雨淋溶量增加而减弱,两种磷肥处理下,土壤5～55 cm深度范围内Pb的平均含量分别为47.23 mg·kg-1(DAP)和53.21 mg·kg-1(TCP),不同酸... 相似文献