共查询到20条相似文献，搜索用时 140 毫秒
1.
广西石漠化地区不同植被恢复样地的土壤微生物量比较 总被引：1，自引：0，他引：1
用土壤微生物研究方法和化学分析方法,对广西石漠化地区不同植被恢复样地土壤微生物量碳、氮和磷以及土壤呼吸速率进行测定,从不同植被类型及土壤理化性质等角度,对不同植被恢复调查样地的生态恢复效果进行比较。结果表明:土壤微生物量碳、磷以及土壤呼吸在不同植被样地之间有显著差异;土壤微生物量碳的大小排序为:乔灌混交林青檀任豆青冈侧柏阴香青檀+鞍叶羊蹄甲剑麻枫香湿地松吊丝竹湿地松+桉树桉树光板地;在一定时间范围内,随着植被恢复年限增加,土壤微生物量碳含量逐渐增加,土壤微生物量氮也呈现缓慢增加,但土壤微生物量磷却呈现明显的波动性,出现先升后降现象;土壤微生物量与土壤水分、有机质、含氮量、脲酶活性等土壤肥力因子有较好的相关性;以青檀、侧柏、阴香、任豆等乡土植物为优势种的样地,其土壤微生物量明显大于外来物种湿地松和桉树为优势种的样地。因此,在石漠化地区植被恢复过程中,应首先考虑使用青檀、侧柏、阴香、任豆等乡土树种。 相似文献
2.
INTRODUCTIONTheimportanceofmicroorganismstosoilfer tilityandsoilqualityhasbeencommonlyaccept ed (Smithetal.,1 990 ;Brookes,1 995;Da lal,1 998;Wicketal.,1 998) .Soilmicrobialbiomassasanimportantmicrobialpropertyhasbeenextensivelystudiedsinceitisthelivingco… 相似文献
3.
A laboratory incubation experiment was conducted to study the effect of copper as cupric sulfate (CuSO4.5H2O), and lead as lead acetate (Pb (OAc)2) on the size of the microbial biomass in red soil. The metals were applied, separately at six different levels: Cu at 50,
100, 200, 300, 400, and 600 μg·g−1 soil and Pb at 100, 200, 400, 600, 800, and 1000 μg·g−1 soil. In comparison to uncontaminated soil, the microbial biomass carbon (Cmic) and biomass nitrogen (Nmic) decreased sharply in soils contaminated with Cu and Pb. The microbial biomass C:N ratio in the metal contaminated soil was
observed to be considerably higher than that in untreated control. Between the two tested metals, Cu displayed greater biocidal
effect on microbial biomass carbon and nitrogen than Pb, showing their relative toxicity in the order: Cu≫Pb.
Project (No. 49671050) supported by National Natural Science Foundation of China.
Wa’el Mohamad—Former Ph. D. Student of Zhejiang University and is working in Ministry Of Agriculture (P. O. box. 2099), Amman,
Jordan. 相似文献
4.
Heavy metal pollution of soil is a significant environmental problem and has its negative impact on human health and agriculture. Rhizosphere, as an important interface of soil and plant, plays a significant role in phytoremediation of contaminated soil by heavy metals, in which, microbial populations are known to affect heavy metal mobility and availability to the plant through release of chelating agents, acidification, phosphate solubilization and redox changes, and therefore, have potential to enhance phytoremediation processes. Phytoremediation strategies with appropriate heavy metal-adapted rhizobacteria have received more and more attention. This article paper reviews some recent advances in effect and significance of rhizobacteria in phytoremediation of heavy metal contaminated soils. There is also a need to improve our understanding of the mechanisms involved in the transfer and mobilization of heavy metals by rhizobacteria and to conduct research on the selection of microbial isolates from rhizosphere of plants growing on heavy metal contaminated soils for specific restoration programmes. 相似文献
5.
采用营养液培养方式,探讨和比较硝态氮(NO3--N)和铵态氮(NH4+-N)两种不同供氮形态及其供应水平(0、3、7.5、15、22.5、30、37.5 mmol/L)下,供试玉米利民15和皖玉9号的生物学性状对以磷酸钙模拟的低生物有效磷胁迫的适应性差异。结果表明:当供氮水平低于22.5 mmol/L时,对玉米供应NH4+-N或NO3--N均可产生提高其对低生物有效磷胁迫适应性的效应。随供氮水平的升高,在两种供氮形态营养条件下,玉米幼苗植株生物量、地上部和根系干重、株高、叶面积和根体积的变化趋势均基本呈现报酬递减规律,而当供氮水平在0～7.5 mmol/L变化时,玉米的生物量干重均出现最高值。不同品种玉米对NH4+-N和NO3--N营养的响应既存在共性:NO3--N营养玉米植株株高和根体积始终高于NH4+-N营养植株,但也存在基因型差异。从植株含磷量分析,当氮水平高于3 mmol/L时,NH4+-N营养利民15的磷含量始终高于NO3--N营养玉米;而皖玉9号则在供NH4+-N水平高于22.5 mmol/L时,出现磷含量低于等氮水平下的NO3--N营养玉米的现象;其中利民15的植株磷含量与其生物量干重之间呈极显著的负相关关系(r=-0.77**,n=11),而皖玉9号的植株磷含量则与其生物量干重之间呈极显著的正相关关系(r=0.96**,n=11)。此外,在等氮水平下,两种供氮形态营养玉米的叶面积、单位叶面积光合速率、单株水平的根系活力之间没有明显的差异,因此,在低生物有效磷胁迫条件下,玉米在不同供氮形态营养条件下的适应性机制不同,其适应性强弱主要取决于是否为适宜的供氮水平。 相似文献
6.
Heavy metal pollution of soil is a significant environmental problem and has its negative impact on human health and agriculture. Rhizosphere, as an important interface of soil and plant, plays a significant role in phytoremediation of contaminated soil by heavy metals, in which, microbial populations are known to affect heavy metal mobility and availability to the plant through release of chelating agents, acidification, phosphate solubilization and redox changes, and therefore, have potential to enhance phytoremediation processes. Phytoremediation strategies with appropriate heavy metal-adapted rhizobacteria have re-ceived more and more attention. This article paper reviews some recent advances in effect and significance of rhizobacteria in phytoremediation of heavy metal contaminated soils. There is also a need to improve our understanding of the mechanisms in-volved in the transfer and mobilization of heavy metals by rhizobacteria and to conduct research on the selection of microbial isolates from rhizosphere of plants growing on heavy metal contaminated soils for specific restoration programmes. 相似文献
7.
Microbial activity and community diversity in a variable charge soil as affected by cadmium exposure levels and time 总被引：1，自引：0，他引：1
Effects of cadmium (Cd) on microbial biomass, activity and community diversity were assessed in a representative variable charge soil (Typic Aquult) using an incubation study. Cadmium was added as Cd(NO3)2> to reach a concentration range of 0～16 mg Cd/kg soil. Soil extractable Cd generally increased with Cd loading rate, but decreased with incubation time. Soil mi-crobial biomass was enhanced at low Cd levels (0.5～1 mg/kg), but was inhibited consistently with increasing Cd rate. The ratio of microbial biomass C/N varied with Cd treatment levels, decreasing at low Cd rate (<0.7 mg/kg available Cd), but increasing progressively with Cd loading. Soil respiration was restrained at low Cd loading (<1 mg/kg), and enhanced at higher Cd levels. Soil microbial metabolic quotient (MMQ) was generally greater at high Cd loading (1～16 mg/kg). However, the MMQ is also affected by other factors. Cd contamination reduces species diversity of soil microbial communities and their ability to metabolize different C substrates. Soils with higher levels of Cd contamination showed decreases in indicator phospholipids fatty acids (PLFAs) for Gram-negative bacteria and actinomycetes, while the indicator PLFAs for Gram-positive bacteria and fungi increased with increasing levels of Cd contamination. 相似文献
8.
A field experiment was conducted to study the response of individual leaf spectral reflectance to five levels of nitrogen
fertilizer treatments in rice (Oriza sativa L.) plants. Sampling was combined through a rice canopy at upper, medium and low levels for biomass, nitrogen and water content
measurements with spectral signals from the leaves. The vertical gradients of leaf biomass, nitrogen and water contents were
associated with the nitrogen availability during tillering, panicle formation, initial heading and heading. Rice plants treated
with the lowest rate of N could be characterized with the lowest value of gradient in leaf biomass and leaf water content
and the highest value of gradient in leaf N concentration. A spectral gradient of single reflectance (R), ratio (RVI) and
normalized difference (ND) of two individual reflectances was defined as this yielded a better relationship between the spectral
data and leaf nitrogen concentration. The results suggested the spectral gradients may be used as an improved diagnostic tool
for nitrogen status.
Project (49771056) supported by Natural Science Foundation of China(NSFC). 相似文献
9.
ＩＮＴＲＯＤＵＣＴＩＯＮＶｉｓｉｂｌｅａｎｄｎｅａｒｉｎｆｒａｒｅｄｒｅｆｌｅｃｔｉｏｎｓｐｅｃｔｒｏｓ ｃｏｐｙｗａｓｐｒｏｖｅｄｉｎｒｅｃｅｎｔｙｅａｒｓｔｏｏｆｆｅｒｔｈｅｐｏｓ ｓｉｂｉｌｉｔｙｏｆｏｂｔａｉｎｉｎｇａｒａｐｉｄ ,ｎｏｎ ｄｅｓｔｒｕｃｔｉｖｅｅｓｔｉ ｍａｔｉｏｎｏｆｐｌａｎｔｎｉｔｒｏｇｅｎｃｏｎｔｅｎｔｓ(Ｔｈｏｍａｓｅｔａｌ.,1 972 ;Ｈｉｎｚｍａｎｅｔａｌ.,1 986;Ｔａｋｅｂｅｅｔａｌ.,1 990 ;Ｆｉｌｅｌｌａｅｔａｌ.,1 995;Ｂｌａｃｋｍｅｒｅｔａｌ.,1 994 ,1 996;Ｌａｄｈａ… 相似文献
10.
南美蟛蜞菊在煤矿废弃地的栽培与应用研究 总被引：1，自引：0，他引：1
本研究以南美蟛蜞菊Wedelia trilobata为实验材料,选择煤矸石土进行栽培试验研究,选择普通有机土作对照,在栽培期间定期对南美蟛蜞菊的鲜重、生长速度、新芽数、新叶数、叶色等指标进行观察测定。实验结果表明：南美蟛蜞菊在煤矸石土生长40d时叶色深绿;新增茎节数与有机土植株之比为31：48,新叶数与有机土植株之比为96：182,生物量（鲜重）没有出现显著差异。说明南美蟛蜞菊在煤矸石土栽培有良好的生长适应性。适宜用于煤矸石土植被恢复和重建材料． 相似文献
11.
土壤有机质分组方法研究进展评述 总被引：1，自引：0，他引：1
毛艳玲 《泉州师范学院学报》2008,26(6):70-75
土壤有机质包含各种各样的功能库,其功能库有特定的稳定机制及周转速率,目前已经有许多分离和分析土壤有机质组分的方法．土壤有机质分组方法一般可分为物理分组和化学分组方法,将这两种方法相结合是今后研究的重点．活性土壤有机质可通过土壤微生物量、轻组有机质和颗粒有机质来表达．不同分组方法分离出的组分具有不同物理化学性质,使土壤有机质的稳定性不同,但所分离出的有机质组分不是组成和结构均一的化合物,而是具有某一特性的一类化合物的混合物．至今为止．所有用于分离有机质组分的方法仍然无法产生同质或功能相似的土壤有机质库,无法体现土壤特定的稳定机制．今后还需通过结合微生物标记、同位素标记等方法,从异质组分中区分出功能组分,这也将是土壤有机质分组未来研究的方向． 相似文献
12.
黄佳聪 《齐齐哈尔师范高等专科学校学报》2006,(2):61-63
红壤是遍布于武夷山地区面积最大的低产土壤类型之一，典型红壤的pH值、有机质含量、机械组成等理化性质对土壤的肥力有重大的影响。通过与其它土壤类型的比较，分析不利于植物生长的特征；同时。结合武夷山典型红壤的现状，充分考虑武夷山地区经济效益、生态效益、社会效益的一致性，针对存在的问题提出不同的合理改良模式，促进武夷山地区的经济发展。 相似文献
13.
INTRODUCTION Biosphere pollution by heavy metals and nu-cleotides was accelerated dramatically during the last few decades due to mining, smelting, manufacturing, treatment of agricultural soils with agro-chemicals and soil sludge, etc. Problems associated with the contamination of soil and water such as animal wel-fare, health, fatalities and disruptions of natural eco-systems are well documented (He et al., 2005). Heavy metals such as Pb, Cr, As, Cu, Cd, and Hg, being added to our so… 相似文献
14.
It is important to research the rules about accumulation and distribution of arsenic and cadmium by tea plants, which will give us some scientific ideas about how to control the contents of arsenic and cadmium in tea. In this study, by field inves- tigation and pot trial, we found that mobility of arsenic and cadmium in tea plants was low. Most arsenic and cadmium absorbed were fixed in feeding roots and only small amount was transported to the above-ground parts. Distribution of arsenic and cadmium, based on their concentrations of unit dry matter, in tea plants grown on un-contaminated soil was in the order: feeding roots>stems≈main roots>old leaves>young leaves. When tea plants were grown on polluted soils simulated by adding salts of these two metals, feeding roots possibly acted as a buffer and defense, and arsenic and cadmium were transported less to the above- ground parts. The concentration of cadmium in soil significantly and negatively correlated with chlorophyll content, photosyn- thetic rate, transpiration rate and biomass production of tea plants. 相似文献
15.
Mycorrhizoremediation an enhanced form of phytoremediation 总被引：2，自引：0，他引：2
Khan AG 《Journal of Zhejiang University. Science. B》2006,7(7):503-514
Study of plant roots and the diversity of soil micro biota, such as bacteria, fungi and microfauna associated with them, is important for understanding the ecological complexities between diverse plants, microbes, soil and climates and their role in phytoremediation of contaminated soils. The arbuscular mycorrhizal fungi （AMF） are universal and ubiquitous rhizosphere mi- croflora forming symbiosis with plant roots and acting as biofertilizers, bioprotactants, and biodegraders. In addition to AMF, soils also contain various antagonistic and beneficial bacteria such as root pathogens, plant growth promoting rhizobacteria including free-living and symbiotic N-fixers, and mycorrhiza helping bacteria. Their potential role in phytoremediation of heavy metal （HM） contaminated soils and water is becoming evident although there is need to completely understand the ecological complexities of the plant-microbe-soil interactions and their better exploitation as consortia in remediation strategies employed for contaminated soils. These multitrophic root microbial associations deserve multi-disciplinary investigations using molecular, biochemical, and physiological techniques. Ecosystem restoration of heavy metal contaminated soils practices need to incorporate microbial biotechnology research and development. This review highlights the ecological complexity and diversity of plant-microbe-soil combinations, particularly AM and provides an overview on the recent developments in this area. It also discusses the role AMF play in phytorestoration of HM contaminated soils, i.e. mycorrhizoremediation. 相似文献
16.
Eleven red soils varying in land use and fertility status were used to examine the effect of land use on microbial biomass-C,-N
and-P. Microbial biomass-C in the red soils ranged from about 68 mg C/kg to 225 mg C/kg, which is generally lower than that
reported from other types of soil, probably because of low organic matter and high acidity in the red soils. Land use had
considerable effects on the amounts of soilC
mic. TheC
mic was the lowest in eroded fallow land, followed by woodland, tea garden, citrus grove and fallow grassland, and the highest
in vegetable and paddy fields. There was significant correlation betweenC
mic and organic matter content, suggesting that the influence of land use onC
mic is mainly related to the input and accumulation of organic matter. Microbial biomass-N in the soils ranged from 12.1 Nmg/kg
to 31.7 Nmg/kg and was also affected by land use. The change ofN
mic with land use was similar to that ofC
mic. The microbial C/N ratio ranged from 5.2 to 9.9 and averaged 7.6. TheN
mic was significantly correlated with soil total N and available N. Microbial biomass-P in the soils ranged from 4.5 mg P/kg
to 52.3 mg P/kg. The microbial C/P ratio was in the range of 4–23. TheP
mic was relatively less affected by land use due to differences in fertilization practices for various land use systems.
Project (No. 40025104) supported by National Outstanding Youth Foundation of China 相似文献
17.
An incubation study was conducted to investigate the effects of metsulfuron-methyl herbicide on the soil microbial biomass
in loamy sand soil. The herbicide was applied to the soil at four concentrations: control, 0.01, 0.10, and 1.00 μg·g−1 soil. Determinations of microbial biomass-C and microbial biomass-N contents were carried out 1, 3, 5, 7, 10, 15, 25, and
45 days after herbicide application. In comparison to untreated soil, the microbial biomass-C and biomass-N decreased significantly
in soils treated with herbicide at concentrations of 0.1 and 1.0 μg·g−1 soil within the first 7 days of incubation. The application of metsulfuron-methyl herbicide to the soil reduced the Cmic/Corg and Nmic/Ntotal percentages, which decreased with increasing application rate of metsulfuron-methyl herbicide. Compared to the untreated
control, a marked increase in the microbial biomass C: N ratio was observed in the herbicide treated soil. This effect was
transitory and was significant only at the higher rates of metsulfuron-methyl.
Project supported by NSFC (No. 49871044) and the Laboratory of Materials Cycling in Pedosphere, Academia Sinica. 相似文献
18.
Studies on nutrient uptake of rice and characteristics of soil microorganisms in a long-term fertilization experiments for irrigated rice 总被引：2，自引：0，他引：2
The ecosystem characteristics of soil microorganism and the nutrient uptake of irrigated rice were investigated in a split-block experiment with different fertilization treatments, including control (no fertilizer application), PK, NK, NP, NPK fertilization, in the main block, and conventional rice and hybrid rice comparison, in the sub block. Average data of five treatments in five years indicated that the indigenous N supply (INS) capacity 相似文献
19.
Toxicity of cadmium to soil microbial biomass and its activity：Effect of incubation time on Cd ecological dose in a paddy soil 总被引：4，自引：0，他引：4
INTRODUCTION Cadmium (Cd) is ubiquitous in the human en-vironment and has been recognized as one of the mostdeleterious heavy metal pollutants (Robards andWorsfold, 1991; Christine, 1997). It may easily movefrom soil to food plants through root absorption andaccumulate in their tissues (Oliver, 1997). In this way,Cd may enter the food chain and affect human health(Adriano, 1986). Among many heavy metals pollut-ing soil, Cd is of concern because of its potentiallyharmful effects on… 相似文献
20.
Annual ryegrass (Lolium multiflorum Lam.) was grown in paddy soil in pots under different phosphorus (P) fertilizer treatments to investigate changes of P fractions and microbial community of the soil. The treatments included Kunyang phosphate rock (KPR) applications at 50 mg P/kg (KPR50) and 250 mg P/kg (KPR250), mono-calcium phosphate (MCP) application at 50 mg P/kg (MCP50), and the control without P application. The results showed that KPR50, KPR250, and MCP50 applications significantly increased the dry weight of the ryegrass by 13%, 38%, and 55%, and increased P uptake by 19%, 135%, and 324%, respectively. Compared with MCP50, the relative effectiveness of KPR50 and KPR250 treatments in ryegrass production was about 23% and 68%, respectively. After one season ofryegrass growth, the KPR50, KPR250, and MCP50 applications increased soil-available P by 13.4%, 26.8%, and 55.2%, respectively. More than 80% of the applied KPR-P remained as HCI-P fraction in the soil. Phospholipid fatty acid (PLFA) analysis showed that the total and bacterial PLFAs were significantly higher in the soils with KPR250 and MCP50 treatments compared with KPR50 and control. The latter had no significant difference in the total or bacterial PLFAs. The KPR50, KPR250, and MCP50 treatments increased fungal PLFA by 69%, 103%, and 69%, respectively. Both the principal component analysis and the cluster analysis of the PLFA data suggest that P treatments altered the microbial community composition of the soils, and that P availability might be an important contributor to the changes in the microbial community structure during the ryegrass growth in the paddy soils. 相似文献