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71.
An in vitro antagonism test is a typical procedure for the selection of potential biocontrol strains. However, the traditional method of screening antagonistic bacteria in vitro is a time consuming method when conducting large-scale screening trials. In this study, an improved method for the selection of antagonistic bacteria in vitro from compost was established based on the traditional method. 21 Antagonistic bacteria out of 33 target strains isolated from vinegar waste compost using the improved method. The 16S rDNA gene showed the 21 strains all belonged to the Bacillus genus and 18 different types of fingerprints were obtained by enterobacterial repetitive inter-genic consensus (ERIC)-PCR. 18 Selected strains which had the unique fingerprints all exhibited broad-spectrum antagonism towards the tested fungi and at least two enzyme activities in vitro. Among them, majority of the isolates were siderophore producer, some of them showed nitrogen-fixing ability and small of them were IAA producer. Four out of five selected strains were found both to be effective in controlling wilt and damping-off disease and four strains showed strong growth-promoting activities for cucumber seedlings under greenhouse conditions. Thus, these results demonstrated that the improved method was an effective and rapid means to screen potential antagonistic microorganisms in vitro. The results also showed that Bacillus sp. strains in vinegar waste compost exhibited antibiosis against fungal pathogens and promoted the growth of cucumber seedlings.  相似文献   
72.
Extensive green roofs substrates should meet a list of physicochemical and biochemical requirements to be used as a basis for plant growth: high water holding capacity, good aeration, low bulk density, and proper drainage are some of them. In recent years, the impact of different organic matter doses and the substrate depth on the subsequent plant growth have been deeply studied. By contrast, there are not many publications about the effect of the inorganic component of these substrates on plant development and C and N sequestration potential by the green roof system, and even more under semi-arid Mediterranean conditions. Four substrates were made by mixing the same compost, at 10% by volume, with different inorganic materials: CsB (compost, silica sand, and crushed bricks; 1:1:8), CB (compost and crushed bricks; 1:9), CSB (compost, clay-loam soil, and crushed bricks; 1:1:8), and CsS (compost, silica sand, and clay-loam soil; 1:1:8). These were placed, a depth of 10 cm, on “cultivation tables” in an experimental farm located in the SE of Spain. Two native species were sown in each substrate: Lotus creticus and Asteriscus maritimus. Physicochemical, nutritional, and biochemical properties of the substrates as well as the plant development were evaluated during a 10-month experiment. The CsB and CSB mixtures had good physicochemical properties (high porosity and acceptable water holding capacity) although the levels of C, N, and humic substances were higher in the soil-containing substrates than in the CB and CsB mixtures. The hydrolytic enzyme activity was also promoted in these mixtures. The plant growth pattern showed differences regarding the inorganic composition of the substrate; L. creticus had superior development in the CsB substrate and A. maritimus was able to grow in all tested substrate mixtures, although its cover was low, being a more versatile candidate to establish a green roof cover. The greatest C and N sequestration potential was achieved by the CsS mixture, reaching 1.06 kg TC m−2 of green roof substrate. Therefore, substrate composition impacts the growth of native plant species as well as the C and N sequestration by the green roof system.  相似文献   
73.
Practices that enhance abundance and diversity of generalist predators are often employed with the objective of improving biological control of insect pests. Ground beetles and other predators can prey on blueberry maggot, an important pest of blueberries, when mature larvae pupate in the ground. We conducted mesocosm and field experiments to determine if Pterostichus melanarius, a common predatory ground beetle, lowers maggot numbers in compost mulch or when predator and alternative prey abundances are manipulated. At background (field) densities of alternative prey, increasing densities of P. melanarius did not significantly reduce pest numbers in mesocosms containing compost or soil. When alternative prey were removed from compost, beetles reduced pest numbers by up to 35%. In field experiments, maggot numbers were higher when beetles and other predators were excluded from soil plots, but beetle exclusion had no effect in compost plots where both predator and alternative prey numbers were high. Our results indicate that there can be some reduction of blueberry maggot by P. melanarius and other potential predators when there are few alternative prey. However, despite attracting large numbers of predators compost mulch did not lead to a significant reduction in blueberry maggot; in fact, the high abundance of alternative food associated with compost appeared to interfere with beetle predation on blueberry maggot.  相似文献   
74.
Summary The macromolecular configuration of humic acid sample obtained from Farm Yard Manure was investigated by viscometric measurements at varying sample concentrations and in presence of a neutral electrolyte. The humic acid molecule behaved like a linear flexible colloid at lower sample concentrations and rigid rod like or sphereo-colloid polyelectrolyte at higher sample concentrations. The polymeric behaviour was alsos shown in the presence of high amount of neutral electrolyte. An analysis of the data for particle weight, volume and axial ratio showed the molecular configuration as rod like.  相似文献   
75.
变性梯度凝胶电泳在堆肥微生物研究中的应用   总被引:4,自引:0,他引:4  
对当前堆肥中微生物种群分布及其对有机物分解作用的研究进行分析,论述了分子生物技术中的变性梯度凝胶电泳(DGGE)的特点。将DGCE与PCR扩增技术相结合,可用于研究自然菌种堆肥和人工培养驯化菌种堆肥过程中微生物的演替规律,为研究和筛选堆肥中的微生物提供更加有效、快速的信息,促进堆肥技术的发展。  相似文献   
76.
Determination of thermal properties of composting bulking materials   总被引:2,自引:0,他引:2  
Thermal properties of compost bulking materials affect temperature and biodegradation during the composting process. Well determined thermal properties of compost feedstocks will therefore contribute to practical thermodynamic approaches. Thermal conductivity, thermal diffusivity, and volumetric heat capacity of 12 compost bulking materials were determined in this study. Thermal properties were determined at varying bulk densities (1, 1.3, 1.7, 2.5, and 5 times uncompacted bulk density), particle sizes (ground and bulk), and water contents (0, 20, 50, 80% of water holding capacity and saturated condition). For the water content at 80% of water holding capacity, saw dust, soil compost blend, beef manure, and turkey litter showed the highest thermal conductivity (K) and volumetric heat capacity (C) (K: 0.12–0.81 W/m °C and C: 1.36–4.08 MJ/m3 °C). Silage showed medium values at the same water content (K: 0.09–0.47 W/m °C and C: 0.93–3.09 MJ/m3 °C). Wheat straw, oat straw, soybean straw, cornstalks, alfalfa hay, and wood shavings produced the lowest K and C values (K: 0.03–0.30 W/m °C and C: 0.26–3.45 MJ/m3 °C). Thermal conductivity and volumetric heat capacity showed a linear relationship with moisture content and bulk density, while thermal diffusivity showed a nonlinear relationship. Since the water, air, and solid materials have their own specific thermal property values, thermal properties of compost bulking materials vary with the rate of those three components by changing water content, bulk density, and particle size. The degree of saturation was used to represent the interaction between volumes of water, air, and solids under the various combinations of moisture content, bulk density, and particle size. The first order regression models developed in this paper represent the relationship between degree of saturation and volumetric heat capacity (r = 0.95–0.99) and thermal conductivity (r = 0.84–0.99) well. Improved knowledge of the thermal properties of compost bulking materials can contribute to improved thermodynamic modeling and heat management of composting processes.  相似文献   
77.
Rotary drum composting of vegetable waste and tree leaves   总被引:2,自引:0,他引:2  
High rate composting studies on institutional waste, i.e. vegetable wastes, tree leaves, etc., were conducted on a demonstration-scale (3.5 m3) rotary drum composter by evaluating changes in some physico-chemical and biological parameters. During composting, higher temperature (60–70 °C) at inlet zone and (50–60 °C) at middle zone were achieved which resulted in high degradation in the drum. As a result, all parameters including TOC, C/N ratio, CO2 evolution and coliforms were decreased significantly within few days of composting. Within a week period, quality compost with total nitrogen (2.6%) and final total phosphorus (6 g/kg) was achieved; but relatively higher final values of fecal coliforms and CO2 evolution, suggested further maturation. Thus, two conventional composting methods namely windrow (M1) and vermicomposting (M2) tried for maturation of primary stabilized compost. By examining these methods, it was suggested that M2 was found suitable in delivering fine grained, better quality matured compost within 20 days of maturation period.  相似文献   
78.
堆肥环境中高浓度腐殖酸的存在阻碍了对这个环境中的未培养微生物的宏基因组研究。我们提出了一个确实可行的提取堆肥环境DNA的方法, 这个方法通过使用Sephadex G200+酸洗PVPP层析柱与电洗脱两步纯化的方法成功地纯化堆肥环境来源的DNA, 用这个DNA成功构建了一个包含约10万个克隆的柯斯质粒文库。从这个文库中筛选到一个新的β-葡萄糖苷酶基因。针对文库低的阳性筛选率问题, 利用分子技术研究了不同的分离速度对提取到的总DNA中真核生物DNA量的影响, 以减少文库中真核生物DNA的污染。  相似文献   
79.
Soil amendment with two types of composts: animal manure (AC) and vegetable waste (VC) induced composts have potential to alleviate Cd toxicity to maize in contaminated soil. Therefore, Cd mobility in waste water irrigated soil can be addressed through eco-friendly and cost effective organic soil amendments AC and VC that eventually reduces its translocation from polluted soil to maize plant tissues. The comparative effectiveness of AC and VC at 3% rate were evaluated on Cd solubility, its accumulation in maize tissues, translocation from root to shoot, chlorophyll contents, plant biomass, yield and soil properties (pH, NPK, OM). Results revealed that the addition of organic soil amendments significantly minimized Cd mobility and leachability in soil by 58.6% and 47%, respectively in VC-amended soil over control. While, the reduction was observed by 61.7% and 57%, respectively when AC was added at 3% over control. Comparing the control soil, Cd uptake effectively reduced via plants shoots and roots by 50%, 46% respectively when VC was added in polluted soil. However, Cd uptake was decreased in maize shoot and roots by 58% and 52.4% in AC amended soil at 3% rate, respectively. Additionally, NPK contents were significantly improved in polluted soil as well as in plant tissues in both composts amended soil Comparative to control, the addition of composts significantly improved the maize dry biomass and chlorophyll contents at 3% rate. Thus, present study confirmed that the addition of animal manure derived compost (AC) at 3% rate performed well and might be consider the suitable approach relative to vegetable compost for maize growth in polluted soil.  相似文献   
80.
鸡粪堆肥的微生物变化规律研究   总被引:1,自引:0,他引:1  
目的:研究鸡粪堆肥中细菌、放线菌和真菌数量的变化规律,为有机堆肥提供技术参数。方法:采取稀释倒平板法和涂布法对堆肥样品进行计数。结果:在发酵过程中,菌数量变化在肥料表面上基本是呈先下降后上升最后达到稳定状态。其中细菌在30cm和60cm深处趋于平稳,真菌在30cm和60cm深处先上升再下降再上升,在第12d后有个急速下降的过程。放线菌在30cm和60cm深处数量比较少。而在后熟发酵过程中,3种菌数的变化规律比较平稳结论:细菌和真菌的生长和繁殖都会抑制放线菌的生长,其中细菌作用大,真菌次之。  相似文献   
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