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1.
植物、土壤及土壤管理对土壤微生物群落结构的影响 总被引:24,自引:2,他引:24
土壤微生物是土壤生态系统的重要组成部分,对土壤微生物群落结构多样性的研究是近年来土壤生态学研究的热点。本文综述了有关植物、土壤类型以及土壤管理措施对土壤微生物群落结构影响的最新研究结果,指出植物的作用因植物群落结构多样性、植物种类、同种植物不同的基因型,甚至同一植物不同根的区域而异;而土壤的作用与土壤质地和有机质含量等因素有关;植物和土壤类型在对土壤微生物群落结构影响上的作用存在互作关系。不同的土壤管理措施对土壤微生物群落结构影响较大,长期连作、大量的外援化学物质的应用降低了土壤微生物的多样性;而施用有机肥、免耕可以增加土壤微生物群落结构多样性,有利于维持土壤生态系统的功能。 相似文献
2.
Bouma Tjeerd J. Nielsen Kai L. Eissenstat David M. Lynch Jonathan P. 《Plant and Soil》1997,195(2):221-232
Little information is available on the variability of the dynamics of the actual and observed root respiration rate in relation to abiotic factors. In this study, we describe I) interactions between soil CO2 concentration, temperature, soil water content and root respiration, and II) the effect of short-term fluctuations of these three environmental factors on the relation between actual and observed root respiration rates. We designed an automated, open, gas-exchange system that allows continuous measurements on 12 chambers with intact roots in soil. By using three distinct chamber designs with each a different path for the air flow, we were able to measure root respiration over a 50-fold range of soil CO2 concentrations (400 to 25000 ppm) and to separate the effect of irrigation on observed vs. actual root respiration rate. All respiration measurements were made on one-year-old citrus seedlings in sterilized sandy soil with minimal organic material.Root respiration was strongly affected by diurnal fluctuations in temperature (Q10 = 2), which agrees well with the literature. In contrast to earlier findings for Douglas-fir (Qi et al., 1994), root respiration rates of citrus were not affected by soil CO2 concentrations (400 to 25000 ppm CO2; pH around 6). Soil CO2 was strongly affected by soil water content but not by respiration measurements, unless the air flow for root respiration measurements was directed through the soil. The latter method of measuring root respiration reduced soil CO2 concentration to that of incoming air. Irrigation caused a temporary reduction in CO2 diffusion, decreasing the observed respiration rates obtained by techniques that depended on diffusion. This apparent drop in respiration rate did not occur if the air flow was directed through the soil. Our dynamic data are used to indicate the optimal method of measuring root respiration in soil, in relation to the objectives and limitations of the experimental conditions. 相似文献
3.
A chlorophenol-contaminated soil was tested for the biodegradability in a semi-pilot scale microcosm using indigenous microorganisms. More than 90% of 4-chlorophenol and 2,4,6-trichlorophenol, initially at 30 mg kg–1, were removed within 60 days and 30 mg pentachlorophenol kg–1 was completely degraded within 140 days. The chlorophenols were degraded more effectively under aerobic condition than under anaerobic condition. Soil moisture had a significant effect with the slowest degradation rate of chlorophenols at 25% in the range of 10–40% moisture content. At 25–40%, the rate of chlorophenol degradation was directly related to the soil moisture content, whereas at 10–25%, it was inversely related. Limited oxygen availability through soil agglomeration at 25% moisture content might decrease the degradation rate of chlorophenols. 相似文献
4.
耕作方式对潮土土壤团聚体微生物群落结构的影响 总被引:1,自引:0,他引:1
为探究不同耕作方式对潮土土壤团聚体微生物群落结构和多样性的影响,采用磷脂脂肪酸(PLFA)法测定了土壤团聚体中微生物群落。试验设置4个耕作处理,分别为旋耕+秸秆还田(RT)、深耕+秸秆还田(DP)、深松+秸秆还田(SS)和免耕+秸秆还田(NT)。结果表明:与RT相比,DP处理显著提高了原状土壤和>5 mm粒级土壤团聚体中真菌PLFAs量和真菌/细菌,为真菌的繁殖提供了有利条件,有助于土壤有机质的贮存,提高了土壤生态系统的缓冲能力;提高了5~2 mm粒级土壤团聚体中细菌PLFAs量,降低了土壤革兰氏阳性菌/革兰氏阴性菌,改善了土壤营养状况;提高了<0.25 mm粒级土壤团聚体中微生物丰富度指数。总的来说,深耕+秸秆还田(DP)对土壤团聚体细菌和真菌生物量有一定的提高作用,并且在一定程度上改善了土壤团聚体微生物群落结构,有利于增加土壤固碳能力和保持土壤微生物多样性。冗余分析结果表明,土壤团聚体总PLFAs量、细菌、革兰氏阴性菌和放线菌PLFAs量与土壤有机碳相关性较强,革兰氏阳性菌PLFAs量与总氮相关性较强。各处理较大粒级土壤团聚体微生物群落主要受碳氮比、含水量、pH值和团聚体质量分数的影响,较小粒级土壤团聚体微生物群落则主要受土壤有机碳和总氮的影响。 相似文献
5.
生物质炭对水稻土团聚体微生物多样性的影响 总被引:9,自引:0,他引:9
生物质炭施用对土壤微生物群落结构的影响已有报道,但土壤团聚体粒组中微生物群落对生物质炭施用的响应的研究还相对不足。以施用玉米秸秆生物质炭两年后的水稻土为对象,采用团聚体湿筛法,通过高通量测序对土壤团聚体的微生物群落结构与多样性进行分析,结果表明:(1)与对照相比,生物质炭施用显著促进了大团聚体(2000—250μm)的形成,并提高了团聚体的稳定性。(2)不同粒径团聚体间微生物相对丰度存在显著差异。在未施生物质炭的处理(C0)中,随着团聚体粒径增大,变形菌门、子囊菌门、β-变形杆菌目、格孢腔菌目的相对丰度逐渐降低,而酸杆菌门、担子菌门、粘球菌目、类球囊霉目的相对丰度逐渐升高。(3)生物质炭施用显著改变了团聚体间的微生物群落结构。与C0处理相比,生物质炭施用处理的大团聚体中变形菌门、鞭毛菌门和β-变形杆菌目的相对丰度分别显著提高了14.37%、33.28%和33.82%;微团聚体(250—53μm)中酸杆菌门、子囊菌门和粘球菌目的相对丰度分别显著降低了20.15%、19.93%和17.66%;粉、黏粒组分(<53μm)中担子菌门的相对丰度升高90.25%,而子囊菌门和鞭毛菌门的相对丰... 相似文献
6.
Summary Total porosity and pore-size distribution (p.s.d.) were determined in soil aggregates taken in plots planted with maize and treated with farmyard manure and three rates of compost. Soil aggregates were collected from the soil adherent to the maize roots (root soil aggregates) and from bulk soil (bulk soil aggregates). Mercury intrusion porosimetry was used to evaluate the total porosity and the p.s.d. Treatments did not affect the total porosity of the bulk soil aggregates. The same was observed for the root soil aggregates. However the total porosity of the root soil aggregates was always lower than that of the bulk soil aggregates. The loss of total porosity was found to be due to a decrease in the percentage of larger pores with respect to the total. 相似文献
7.
Available soil nitrogen in relation to fractions of soil nitrogen and other soil properties 总被引:1,自引:0,他引:1
The available N of 27 soils from England and Wales was assessed from the amounts of N taken up over a 6-month period by perennial ryegrass grown in pots under uniform environmental conditions. Relationships between availability and the distribution of soil N amongst various fractions were then examined using multiple regression. The relationship: available soil N (mg kg–1 dry soil)=(Nmin×0.672)+(Ninc×0.840)+(Nmom×0.227)–5.12 was found to account for 91% of the variance in available soil N, where Nmin=mineral N, Ninc=N mineralized on incubation and Nmom=N in macro-organic matter. The N mineralized on incubation appeared to be derived largely from sources other than the macro-organic matter because these two fractions were poorly correlated. When availability was expressed in terms of available organic N as % of soil organic N (Nao) the closest relationship with other soil characteristics was: Nao=[Ninc×(1.395–0.0347×CNmom]+[Nmom×0.1416], where CNmom=CN ratio of the macro-organic matter. This relationship accounted for 81% of the variance in the availability of the soil organic N.The conclusion that the macro-organic matter may contribute substantially to the available N was confirmed by a subsidiary experiment in which the macro-organic fraction was separated from about 20 kg of a grassland soil. The uptake of N by ryegrass was then assessed on two subsamples of this soil, one without the macro-organic matter and the other with this fraction returned: uptake was appreciably increased by the macro-organic matter. 相似文献
8.
Metabolism of soil invertebrates in relation to soil fertility 总被引:1,自引:0,他引:1
9.
Qian Xiang Dong Zhu Min Qiao Xiao-Ru Yang Gang Li Qing-Lin Chen Yong-Guan Zhu 《Environmental microbiology》2023,25(2):505-514
Soil bacteria are diverse and form complicated ecological networks through various microbial interactions, which play important roles in soil multi-functionality. However, the seasonal effects on the bacterial network, especially the relationship between bacterial network topological features and soil resistomes remains underexplored, which impedes our ability to unveil the mechanisms of the temporal-dynamics of antibiotic resistance genes (ARGs). Here, a field investigation was conducted across four seasons at the watershed scale. We observed significant seasonal variation in bacterial networks, with lower complexity and stability in autumn, and a wider bacterial community niche in summer. Similar to bacterial communities, the co-occurrence networks among ARGs also shift with seasonal change, particularly with respect to the topological features of the node degree, which on average was higher in summer than in the other seasons. Furthermore, the nodes with higher betweenness, stress, degree, and closeness centrality in the bacterial network showed strong relationships with the 10 major classes of ARGs. These findings highlighted the changes in the topological properties of bacterial networks that could further alter antibiotic resistance in soil. Together, our results reveal the temporal dynamics of bacterial ecological networks at the watershed scale, and provide new insights into antibiotic resistance management under environmental changes. 相似文献
10.
The disappearance of the organophosphorus insecticide, malathion, from a silt loam soil and from its organic and inorganic components was examined. Half-lives and the time taken for 90% decomposition in nonsterile, sodium azide-treated, and 2.5 Mrad-irradiated soils were similar (3/4–1 1/2 days and 4–6 days, respectively) but breakdown in autoclaved soils was negligible. Decay in nonsterile sand, silt, and clay minus organic matter fractions was 3–6 times slower than that recorded in the original soil. Breakdown of malathion in the clay plus organic matter fraction (organo-mineral complex) was rapid (half-life, 1 day), as was the case in the separated organic matter (half-life, 1 3/4 days). Filter-sterilized organic matter was not as effective in catalyzing the breakdown of malathion (half-life, 4 days), and no loss occurred from any of the autoclaved components. Irradiation doses of 2.5 and 5.0 Mrad had little influence on the ability of soil to degrade malathion. Thereafter, increases up to 20 Mrad had a more drastic, though far from totally inhibitory, effect. Our results suggest that either the colloidal organic matter itself, or a fraction associated with it, is the most important single factor concerned with the rapid breakdown of malathion in the soil studied. Direct microbial metabolism is a slower process and may have a significant role in malathion disappearance in coarsetextured soils low in colloidal organic matter. The catalytic component of the organic matter is suggested to be a stable exoenzyme and is supportive of reports by other workers. The quantitative effect of organo-mineral complex (containing the active degradative ingredient) additions to sand and silt fractions on the rate of subsequent malathion decay is also described. 相似文献
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13.
Bioremediation of pentachlorophenol-contaminated soil by bioaugmentation using activated soil 总被引:11,自引:0,他引:11
C. Barbeau L. Deschênes D. Karamanev Y. Comeau R. Samson 《Applied microbiology and biotechnology》1997,48(6):745-752
The use of an indigenous microbial consortium, pollutant-acclimated and attached to soil particles (activated soil), was
studied as a bioaugmentation method for the aerobic biodegradation of pentachlorophenol (PCP) in a contaminated soil. A 125-l
completely mixed soil slurry (10% soil) bioreactor was used to produce the activated soil biomass. Results showed that the
bioreactor was very effective in producing a PCP-acclimated biomass. Within 30 days, PCP-degrading bacteria increased from
105 cfu/g to 108 cfu/g soil. Mineralization of the PCP added to the reactor was demonstrated by chloride accumulation in solution. The soil-attached
consortium produced in the reactor was inhibited by PCP concentrations exceeding 250 mg/l. This high level of tolerance was
attributed to the beneficial effect of the soil particles. Once produced, the activated soil biomass remained active for 5
weeks at 20 °C and for up to 3 months when kept at 4 °C. The activated attached soil biomass produced in the completely mixed
soil slurry bioreactor, as well as a PCP-acclimated flocculent biomass obtained from an air-lift immobilized-soil bioreactor,
were used to stimulate the bioremediation of a PCP-impacted sandy soil, which had no indigenous PCP-degrading microorganisms.
Bioaugmentation of this soil by the acclimated biomass resulted in a 99% reduction (from 400 mg/kg to 5 mg/kg in 130 days)
in PCP concentration. The PCP degradation rates obtained with the activated soil biomass, produced either as a biomass attached
to soil particles or as a flocculent biomass, were similar.
Received: 31 March 1997 / Received revision: 22 July 1997 / Accepted: 25 August 1997 相似文献
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红壤退化地森林恢复后土壤有机碳对土壤水库库容的影响 总被引:1,自引:0,他引:1
亚热带红壤侵蚀退化地实施生态恢复后生物生产力恢复迅速,但土壤尤其是土壤水库的功能并未获得同步恢复,导致土壤水库对于降水和地表径流的调节能力低下,区域性洪涝灾害和季节性干旱依然突出。采用野外调查和室内分析相结合的方式,研究了南方红壤侵蚀退化地典型植被恢复类型(马尾松与阔叶树复层林、木荷与马尾松混交林、阔叶混交林)0—60cm土层土壤水库各种库容差异,以及土壤总有机碳和活性有机碳密度分布特征,采用典型相关分析方法对土壤水库库容与土壤有机碳密度两组指标进行相关分析。结果表明:随着土层深度的增加,各森林恢复类型死库容呈上升趋势,兴利库容和最大有效库容呈下降趋势,防洪库容变化趋势不明显,木荷与马尾松混交林兴利库容略高。不同森林恢复类型同一土层土壤总有机碳密度均表现为马尾松与阔叶树复层林木荷与马尾松混交林阔叶混交林,而活性有机碳密度则以阔叶混交林最大。典型相关分析表明,土壤有机碳水平对土壤水库库容的增加具有显著的因果影响关系(P=0.01),其中对有机碳水平起到主导性贡献作用的是水溶性有机碳。因此,对于退化红壤地森林恢复初期,可通过适当密植和立体种植,提高林地生物量和土壤碳密度,并在马尾松等先锋树种针叶林分中补植阔叶乔灌木,以增加土壤活性有机碳含量,增大土壤水库容量,从而有利于土壤水库结构和功能以及退化生态系统的快速恢复。 相似文献
16.
Response of changes in soil nutrients to soil erosion on a purple soil of cultivated sloping land
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Severe soil erosion of cultivated sloping land in hilly areas of Sichuan, China, has resulted in deterioration of soil quality, and therefore has an adverse impact on crop production. A hillslope of 110 m in length was selected with a slope steepness of 10.12% where the soils were classified as Regosols. Soil samples for determining 137Cs, soil organic matter (SOM), total N, P, K, available N, P, K and particle size fraction were collected at 10 m intervals along a transect of the hillslope. Loss of soil nutrients owing to soil erosion was studied by using 137Cs technique, and the relationships between 137Cs-derived soil redistribution rates and soil nutrients were established over the cultivated sloping land in hilly areas of Sichuan, China (30o26′N, 104o28′E). The values of SOM, total N, available N, P, K and the soil particle fractions of size < 0.002 mm were smaller at upper and middle slope positions where 137Cs inventories were lower (i.e., soil erosion rates were higher) than at downslope positions where 137Cs inventories were higher (i.e., soil erosion rates were lower). The lowest 137Cs inventories were found at the hilltop, showing that besides erosion owing to water flow, tillage also contributed to soil losses, and intensive tillage was mostly responsible for severe erosion at upper slope positions. There were significant differences in SOM, total N, available N, P, K and the soil particle fractions of size < 0.002 mm between different slope segments, and these properties were significantly correlated with slope length. These soil properties were also significantly correlated with 137Cs inventories, indicating that both 137Cs and nutrient concentrations varied with topographical changes. The variation in soil properties was strongly influenced by erosion-induced soil redistribution, and therefore 137Cs inventories mirroring soil redistribution rates would be considered as an integrated indicator of soil quality. 相似文献
17.
坡耕地紫色土养分空间变异对土壤侵蚀的响应 总被引:15,自引:0,他引:15
坡耕地土壤侵蚀导致土壤质量降低,并因此造成对作物产量的不利影响。利用土壤侵蚀测定的^137Cs示踪技术,结合土壤理化分析,研究了川中丘陵区紫色土坡耕地土壤侵蚀所引起的土壤再分配对养分空间变异性的影响。结果表明,川中丘陵区坡耕地土壤侵蚀是水蚀和耕作侵蚀共同作用的结果,强烈的耕作导致坡上部发生最为严重的土壤侵蚀。土壤侵蚀对土壤特性的空间变异性产生深刻影响,坡上部土壤有机质和养分贫瘠,而在坡下部相对富集;土壤有机质、全N、碱解N、有效P、K以及土壤粘粒含量在不同坡位之间出现显著差异。反映净余土壤再分配速率的^137Cs面积浓度与这些土壤理化特性均有密切的相关性。因此,^137Cs面积浓度可以作为表征侵蚀坡地土壤综合质量的指标。 相似文献
18.
原油进入土壤后会堵塞土壤孔隙,影响土壤斥水性,改变土壤水分运动状况。本研究利用土柱模拟的方法,研究了不同原油污染程度(0、0.5%、1%、2%、4%)对黄绵土和风沙土水分入渗过程的影响。结果表明: 随着原油含量的增加,两种土壤湿润锋的推进速度和入渗速率均减小,土壤原油污染程度为4%时湿润锋运移到土柱底部的所需时间最长,污染程度为0时湿润锋运移到土柱底部的所需时间最短,黄绵土湿润锋达到土柱底部所需最长时间是最短时间的5倍,风沙土最长时间是最短时间的48倍;当湿润锋运移到土柱底部时,黄绵土的累积入渗量随原油含量的增加而减小,而风沙土的累积入渗量先增大后减小;在高浓度(2%、4%)原油处理下,风沙土的累积入渗量曲线出现“翘尾”现象。Kostiakov入渗模型和Philip入渗模型比Green-Ampt模型能更好地模拟不同原油处理下的黄绵土土壤水分入渗过程,但对风沙土而言,两种模型对低浓度(0、0.5%、1%)原油处理的土壤水分入渗过程拟合较好。原油污染能够显著影响土壤水分入渗过程,且对风沙土的影响更大。 相似文献
19.
Distinct impacts of reductive soil disinfestation and chemical soil disinfestation on soil fungal communities and memberships 总被引:2,自引:0,他引:2
Zhao Jun Zhou Xing Jiang Anqi Fan Juanzi Lan Tao Zhang Jinbo Cai Zucong 《Applied microbiology and biotechnology》2018,102(17):7623-7634
Applied Microbiology and Biotechnology - Soil disinfestation is an important agricultural practice to conquer soil-borne diseases and thereby ensure crop productivity. Reductive soil disinfestation... 相似文献
20.
Variations of soil enzyme activities in a temperate forest soil 总被引:3,自引:0,他引:3
Soil enzyme activities (dehydrogenase, urease, phosphatase, and arylsulfatase) in a temperate forest soil were determined
in relation to landscape position and seasons. Overstory of the area is dominated by Quercus mongolica, Kalopanax pictus, Carpicus cordata, and Acer pseudo-sieboldianum. The activities were measured in three patches, namely a north-facing backslope, a ridge, and a south-facing backslope in
autumn and spring over 2 years. In addition, spatially more detailed analysis for phosphatase was conducted before and after
litterfall production in six patches. Dehydrogenase, urease, phosphatase, and arylsulfatase activities varied 1.8–18.5 μg
INT-formazan g−1 h−1, 45.4–347.0 μg NH4
+ g−1 h−1, 0.9–4.5 mmol pNP g−1 h−1, and 0.7–2.6 mmol pNP g−1 h−1, respectively. In general, higher enzyme activities were found in the northern aspect than in the southern aspect. This variation
appears to be related to differences in chemical properties (e.g., Fe, Al, and Mg) of soil as well as distribution of leaf
litter. Two patterns were discernible in relation to seasonal variations. Dehydrogenase and urease exhibited a positive correlation
with mean air temperature, suggesting that temperature would be a major controlling variable for those enzymes. In contrast,
higher activities were detected in autumn for phosphatase and arylsulfatase activities, which appeared to be closely related
to litter production and distribution. Overall results of this study indicate that soil enzyme activities in a forest floor
are influenced by several variables such as temperature, nutrient availability, and input of leaf litter, which are closely
related to landscape position. 相似文献