稻鸭与稻鱼生态系统土壤微生物量N和土壤酶活性动态

在一个水稻生长季节,采用田间采样与室内分析的方法,利用氯仿熏蒸培养法、苯酚钠比色法、TTC比色法、高锰酸钾滴定法和茚三酮比色法测定和研究了稻鸭与稻鱼生态系统稻田土壤微生物量N(MBN)和土壤脲酶、脱氢酶、过氧化氢酶和蛋白酶活性的动态变化,及其与土壤养分和水稻吸N量的相关性.结果表明,(1)随着水稻的生长,土壤微生物量N表现为先上升随后下降,于成熟期有所回升趋势;土壤微生物量N与土壤速效N、全N和全P不相关;由于水稻与微生物对养分的竞争,土壤微生物量N与水稻吸N量不相关;稻田养鸭,养鱼显著地提高了土壤微生物量N.(2)土壤脲酶、脱氢酶和蛋白酶活性都表现出先上升后下降趋势,而过氧化氢酶活性变化不大;稻鸭与稻鱼共作显著地提高了土壤脲酶、脱氢酶和蛋白酶活性,而对过氧化氢酶活性影响不大;线性相关分析表明,在一个稻季内,土壤脲酶和脱氢酶活性与土壤速效N负相关,土壤脲酶、脱氢酶、过氧化氢酶和蛋白酶活性与土壤全N和全P不相关;土壤脲酶、脱氢酶和蛋白酶活性与水稻吸N量呈显著相关.(3)稻田土壤微生物量N与土壤酶不相关.     

Factors influencing soil enzyme activity in China’s forest ecosystems

Enzyme activity (EA) mediates soil organic matter (SOM) degradation, transformation, and mineralization, thereby maintaining the biogeochemical cycles and energy flow of ecosystems. To determine the main factors explaining EA variations in China’s forest ecosystems, we created a database of soil EAs and relevant variables using data from the literature and analysed relationships between EAs and both climatic and edaphic variables. Catalase, phenol oxidase, acid (alkaline) phosphatase, and protease activities differed significantly among different types of forests. Catalase and urease activities were generally higher in primosols, cambisols, and argosols than in ferrosols. EA largely decreased with soil depth and increased with SOM. Phenol oxidase and urease activities were negatively correlated with mean annual temperature (MAT); in contrast, catalase, invertase, and protease activities first decreased (< 2.5 °C), increased (2.5–17.5 °C), and then decreased (> 17.5 °C) with increasing MAT. Although protease activity was slightly positively correlated with mean annual precipitation (MAP), catalase, phenol oxidase, and urease activities were all negatively related to MAP. Catalase, invertase, acid (alkaline) phosphatase, urease, and protease activities first increased (< 2000 m.a.s.l.) and then decreased (2000–4100 m.a.s.l.) with increasing elevation. Principal component analysis revealed most EAs to be correlated with climate conditions and soil pH. These findings suggest that climatic and edaphic variables directly and indirectly correlate with forest type and greatly impact soil EA.     

黄土高原纸坊沟流域不同植物对土壤微生物生物量和土壤酶活性的影响

为了解不同植被类型对土壤微生物生物量和土壤酶活性的影响,以黄土高原纸坊沟流域的9种植物为研究对象,选取撂荒地为参照,分析了各类植被植物根际土土壤微生物生物量、土壤酶活性及其与土壤理化因子的相关性.结果显示:(1)与撂荒地相比,经过植被恢复后,乔木和灌木植被下土壤肥力、微生物生物量和土壤酶活性均有所提高,而草本植被下土壤的碱解氮含量、微生物生物量磷、脲酶活性和过氧化氢酶活性却有所降低.(2)不同植被类型土壤微生物生物量碳和氮、蔗糖酶和碱性磷酸酶活性符合灌木＞乔木＞草本的规律;土壤微生物生物量磷、脲酶和过氧化氢酶活性符合乔木＞灌木＞草本的规律.(3)土壤微生物生物量碳、氮、磷与土壤有机质、全氮及全磷含量呈极显著正相关;4种土壤酶活性与土壤有机质、全氮及碱解氮含量呈极显著正相关.研究表明,黄土高原纸坊沟流域土壤微生物生物量和土壤酶活性受植被类型及土壤养分等因素的共同影响,且人工灌木植被对土壤的恢复作用高于乔木和草本植被.     

生物结皮对铜尾矿废弃地土壤微生物量及酶活性的影响

生物结皮是铜尾矿废弃地自然原生演替的最初阶段.本研究以铜陵杨山冲铜尾矿库和铜官山新铜尾矿库为对象,采用熏蒸浸提和化学分析法研究了两尾矿库不同类型生物结皮下土壤微生物量C、N及脱氢酶、过氧化氢酶、碱性磷酸酶和脲酶活性.结果表明：铜尾矿废弃地上的生物结皮能够显著提高表层尾矿中的微生物量和土壤酶活性,其中藻类结皮对土壤微生物量C、N的影响高于藓-藻混合结皮,藓类结皮的影响最小;随着土壤生物结皮类型的变化,土壤微生物区系也随之变化;各类生物结皮下表层尾矿中土壤酶活性无显著差异.相关分析表明,碱性磷酸酶活性与土壤微生物量、脱氢酶和脲酶活性呈显著正相关,但与土壤pH呈显著负相关.此外,藓类植物假根能够显著提高藓类结皮假根层的微生物量和酶活性.     

重金属Cd、Zn、Cu、Pb对土壤微生物和酶活性的影响

采用室内培养实验(25℃),研究了不同培养时间下重金属Cd、Zn、Cu、Pb(浓度分别为50,800,400,800mg.kg-1)污染对土壤微生物和酶活性的影响。结果表明,土壤蔗糖酶、过氧化氢酶和脱氢酶活性随着培养时间的增加而显著下降,在培养20d的时候达到最小值,然后酶活性缓慢升高。Cu对脲酶活性以及Cd对酸性磷酸酶和脲酶活性的抑制作用随时间增加而增加。土壤微生物生物量碳、细菌、真菌和放线菌数量随培养时间的增加均表现出先降低后升高的变化趋势。Cd和Cu对微生物生物量氮的抑制作用则随着培养时间的增加而增强,在培养30d时微生物生物量氮到达最低值,分别较培养10天减少了12.6%和16.5%。     

Effect of temperate forest tree species on soil dehydrogenase and urease activities in relation to other properties of soil derived from loess and glaciofluvial sand

We investigated the effects of several tree species on dehydrogenase and urease activities in soils derived from two different parent materials (glaciofluvial sand and loess) in forested areas in southern Poland. We hypothesized that coniferous forests (pine, spruce) alter the soil cation exchange capacity (CEC) and decrease soil pH and, therefore, might decrease soil enzyme activities compared with broadleaf species growing on similar soils. Eight paired plots (12 × 12 m) were established on glaciofluvial sand in pine (Pinus sylvestris) + oak (Quercus robur) and spruce (Picea abies) + pine stands, as well as on loess-derived soils: beech (Fagus sylvatica) + pine and hornbeam (Carpinus betulus) + pine stands. Each plot was a 4 × 4 m grid with 16 sampling points. In soil samples pH, soil texture, and organic carbon, nitrogen, base cation contents, dehydrogenase and urease activities were determined. On both parent materials, the soil pH was lower under coniferous species than under broadleaf species. The acidifying effect of tree species on sandy soil was in the order of spruce = pine > oak, while that on loess was pine > beech > hornbeam. Hornbeam and oak increased the soil pH and stimulated enzyme activity in the soil. The content of fine fraction enhanced potential enzyme activities in soils, thus the loess soils had greater dehydrogenase and urease activity. The results suggest that pine stores more soil organic C in association with silt increasing the pool of stabilized soil organic C.     

连作改变土壤性状对甜叶菊产量和品质的影响

为了解连作障碍的产生机理，对甜叶菊(Stevia rebaudiana)连作后的土壤性状变化进行了研究，并探讨土壤性状与叶片干质量和甜菊糖苷之间的相关性。结果表明，连作2 a和3 a的土壤pH值、有机质、速效磷、脲酶、过氧化氢酶、蔗糖酶、磷酸酶和甜叶菊叶片干质量及甜菊糖苷组分含量均无显著差异。连作4 a后，土壤pH值、全氮和速效钾含量显著下降，分别比对照降低了10.07%、14.38%和24.79%，土壤电导率(EC)和速效磷含量显著增加，是对照的2.57和1.70倍；土壤脲酶、蔗糖酶、磷酸酶活性、微生物量碳和微生物量氮在连作4 a降到最低，比对照分别降低了63.68%、72.03%、47.43%、78.35%和41.07；多酚氧化酶则在连作4a达到最高，是对照的4.22倍；与对照相比，连作4a的叶片干质量和甜菊苷含量降低了29.51%和16.00%，莱鲍迪苷A含量则增加了22.19%。叶片干质量及甜菊糖苷含量与土壤性状间存在着相关性。因此，连作通过改变土壤性状影响甜叶菊产量和品质，生产中最大连作年限不宜超过3 a。     

重金属污染区土壤酶活性变化

从福建龙岩新罗区特钢厂污灌区农田采集土壤,测定土壤基本理化性质及脲酶、纤维素酶、碱性磷酸酶、多酚氧化酶、过氧化氢酶活性和Cu、Cd、Pb、Zn含量,探讨重金属污染和土壤性质对土壤酶活性的影响.结果表明： 4种全量或有效态重金属与土壤脲酶、纤维素酶、碱性磷酸酶和多酚氧化酶活性呈显著正相关,与过氧化氢酶活性呈显著或极显著负相关;土壤pH与碱性磷酸酶活性呈极显著正相关,粉粒含量与过氧化氢酶活性呈显著负相关.经通径分析,重金属污染刺激了脲酶、多酚氧化酶和纤维素酶活性,但对碱性磷酸酶活性的影响较小.有效态Cu、Cd、Pb、Zn对过氧化氢酶活性的直接影响并不大,但通过间接途径抑制了过氧化氢酶活性.土壤理化性质对5种土壤酶活性的影响较大,碱解氮直接抑制了脲酶活性;全磷直接刺激了碱性磷酸酶和过氧化氢酶活性,并通过有效磷刺激了纤维素酶活性;有效磷直接刺激了纤维素酶活性,直接抑制了碱性磷酸酶和过氧化氢酶活性;全钾直接抑制了碱性磷酸酶和多酚氧化酶活性;速效钾通过有效磷刺激了纤维素酶活性;土壤颗粒组成明显影响多酚氧化酶和过氧化氢酶活性.5种酶活性与土壤Cu、Cd、Pb、Zn含量之间的关系不明确,因此其活性不是指示土壤Cu、Cd、Pb、Zn污染的良好指标.     

Soil properties of Alhagi sparsifolia community in saline-sodic badlands in west China

A field experiment was conducted to assess the influences of soil chemical, physical, and biological properties of Alhagi sparsifolia community in Linze, Gaotai, and Guazhou County, Gansu province, China. Results showed that soils sampled were generally infertile with low levels of organic matter, available nitrogen, phosphorus, copper, manganese, and zinc with bacteria dominant microbial communities supporting A. sparsifolia. Available potassium and iron were sufficient in the study sites. With increasing soil layer depth, the contents of organic matter, available nitrogen, phosphorus, potassium, manganese, urease, dehydrogenase, bacteria, and actinomyces in the soil decreased significantly (P < 0.05), whereas the concentrations of moisture, available iron, and zinc in the soil increased significantly (P < 0.05). The contents of organic matter, available nitrogen, phosphorus, potassium, iron, manganese, zinc, copper, urease, dehydrogenase, bacteria, and actinomyces showed strong seasonal variations (P < 0.05). All these variables except dehydrogenase, bacteria, and actinomyces were the highest in summer and the lowest in spring. The comprehensive score of soil qualities was the greatest in Linze, medium in Guazhou, and lowest in Gaotai.     

Effects of Silver Nanoparticles on Soil Enzyme Activity of Different Wetland Plant Soil Systems

In the present study, five soil exoenzymes (dehydrogenase, urease, acid phosphatase, neutral phosphatase, and alkaline phosphatase) were investigated in rhizosphere of wetland plants (Iris wilsonii, Arundo donax, and Typha orientalis) treated with silver nanoparticles (0, 0.024, 0.24, 4.80, and 9.60 μg/g dry soil). It was found that Ag NPs were capable of inhibiting all exoenzyme activities tested in this study, with inhibitory effects especially obvious to higher Ag NPs level (4.80 and 9.60 μg/g dry soil). However, for lower Ag NPs concentration (0.024 μg/g dry soil), the adverse effects on exoenzymes was only found in T. orientalis rhizosphere, the exoenzyme activities in rhizosphere of I. wilsonii were less affected. This study suggested that high concentration Ag NPs could negatively affect all soil exoenzyme activities, while the impacts of low Ag NPs level on exoenzyme activities were mainly related to plant species.     

Soil Microbial Biomass,Basal Respiration and Enzyme Activity of Main Forest Types in the Qinling Mountains

Different forest types exert essential impacts on soil physical-chemical characteristics by dominant tree species producing diverse litters and root exudates, thereby further regulating size and activity of soil microbial communities. However, the study accuracy is usually restricted by differences in climate, soil type and forest age. Our objective is to precisely quantify soil microbial biomass, basal respiration and enzyme activity of five natural secondary forest (NSF) types with the same stand age and soil type in a small climate region and to evaluate relationship between soil microbial and physical-chemical characters. We determined soil physical-chemical indices and used the chloroform fumigation-extraction method, alkali absorption method and titration or colorimetry to obtain the microbial data. Our results showed that soil physical-chemical characters remarkably differed among the NSFs. Microbial biomass carbon (Cmic) was the highest in wilson spruce soils, while microbial biomass nitrogen (Nmic) was the highest in sharptooth oak soils. Moreover, the highest basal respiration was found in the spruce soils, but mixed, Chinese pine and spruce stands exhibited a higher soil qCO₂. The spruce soils had the highest Cmic/Nmic ratio, the greatest Nmic/TN and Cmic/Corg ratios were found in the oak soils. Additionally, the spruce soils had the maximum invertase activity and the minimum urease and catalase activities, but the maximum urease and catalase activities were found in the mixed stand. The Pearson correlation and principle component analyses revealed that the soils of spruce and oak stands obviously discriminated from other NSFs, whereas the others were similar. This suggested that the forest types affected soil microbial properties significantly due to differences in soil physical-chemical features.     

重金属污染区土壤酶活性变化——以福建龙岩新罗区特钢厂污水灌溉区为例

从福建龙岩新罗区特钢厂污灌区农田采集土壤,测定土壤基本理化性质及脲酶、纤维素酶、碱性磷酸酶、多酚氧化酶、过氧化氢酶活性和Cu、Cd、Pb、Zn含量,探讨重金属污染和土壤性质对土壤酶活性的影响.结果表明:4种全量或有效态重金属与土壤脲酶、纤维素酶、碱性磷酸酶和多酚氧化酶活性呈显著正相关,与过氧化氢酶活性呈显著或极显著负相关;土壤pH与碱性磷酸酶活性呈极显著正相关,粉粒含量与过氧化氢酶活性呈显著负相关.经通径分析,重金属污染刺激了脲酶、多酚氧化酶和纤维素酶活性,但对碱性磷酸酶活性的影响较小.有效态Cu、Cd、Pb、zn对过氧化氢酶活性的直接影响并不大,但通过间接途径抑制了过氧化氢酶活性.土壤理化性质对5种土壤酶活性的影响较大,碱解氮直接抑制了脲酶活性;全磷直接刺激了碱性磷酸酶和过氧化氢酶活性,并通过有效磷刺激了纤维素酶活性;有效磷直接刺激了纤维素酶活性,直接抑制了碱性磷酸酶和过氧化氢酶活性;全钾直接抑制了碱性磷酸酶和多酚氧化酶活性;速效钾通过有效磷刺激了纤维素酶活性;土壤颗粒组成明显影响多酚氧化酶和过氧化氢酶活性.5种酶活性与土壤Cu、Cd、Pb、Zn含量之间的关系不明确,因此其活性不是指示土壤Cu、Cd、Pb、Zn污染的良好指标.     

Perennial Grass Bioenergy Cropping on Wet Marginal Land: Impacts on Soil Properties,Soil Organic Carbon,and Biomass During Initial Establishment

The control of soil moisture, vegetation type, and prior land use on soil health parameters of perennial grass cropping systems on marginal lands is not well known. A fallow wetness-prone marginal site in New York (USA) was converted to perennial grass bioenergy feedstock production. Quadruplicate treatments were fallow control, reed canarygrass (Phalaris arundinaceae L. Bellevue) with nitrogen (N) fertilizer (75 kg N ha^?1), switchgrass (Panicum virgatum L. Shawnee), and switchgrass with N fertilizer (75 kg N ha^?1). Based on periodic soil water measurements, permanent sampling locations were assigned to various wetness groups. Surface (0–15 cm) soil organic carbon (SOC), active carbon, wet aggregate stability, pH, total nitrogen (TN), root biomass, and harvested aboveground biomass were measured annually (2011–2014). Multi-year decreases in SOC, wet aggregate stability, and pH followed plowing in 2011. For all years, wettest soils had the greatest SOC and active carbon, while driest soils had the greatest wet aggregate stability and lowest pH. In 2014, wettest soils had significantly (p?<?0.0001) greater SOC and TN than drier soils, and fallow soils had 14 to 20% greater SOC than soils of reed canarygrass + N, switchgrass, and switchgrass + N. Crop type and N fertilization did not result in significant differences in SOC, active carbon, or wet aggregate stability. Cumulative 3-year aboveground biomass yields of driest switchgrass + N soils (18.8 Mg ha^?1) were 121% greater than the three wettest switchgrass (no N) treatments. Overall, soil moisture status must be accounted for when assessing soil dynamics during feedstock establishment.     

Variations in soil culturable bacteria communities and biochemical characteristics in the Dongkemadi glacier forefield along a chronosequence

The variations in the soil culturable bacterial communities and biochemical parameters of early successional soils from a receding glacier in the Tanggula Mountain were investigated. We examined low organic carbon (C) and nitrogen (N) contents and enzymatic activity, correlated with fewer bacterial groups and numbers in the glacier forefield soils. The soil pH values decreased, but the soil water content, organic C and total N significantly increased, along the chronosequence. The soil C/N ratio decreased in the early development soils and increased in the late development soils and it did not correlate with the soil age since deglaciation. The activities of soil urease, sucrase, protease, polyphenol oxidase, catalase, and dehydrogenase increased along the chronosequence. The numbers of culturable bacteria in the soils increased as cultured at 25°C while decreased at 4°C from younger soils to older soils. Total numbers of culturable bacteria in the soils cultured at 25°C were significantly positively correlated to the soil total N, organic C, and soil water content, as well as the activities of soil urease, sucrase, dehydrogenase, catalase, and polyphenol oxidase. We have obtained 224 isolates from the glacier forefield soils. The isolates were clustered into 28 groups by amplified ribosomal DNA restriction analysis (ARDRA). Among them, 27 groups and 25 groups were obtained from the soils at 25°C and at 4°C incubation temperatures, respectively. These groups are affiliated with 18 genera that belong to six taxa, viz, Actinobacteria, Gammaproteobacteria, Bacteroidetes, Firmicutes, Alphaproteobacteria, and Betaproteobacteria. The dominant taxa were Actinobacteria, Gammaproteobacteria, and Bacteroidetes in all the samples. The abundance and the diversity of the genera isolated at 25°C incubation temperature were greater than that at 4°C.     

水稻和稗草共生土壤微生物生物量碳及酶活性的变化

以稻田稗草、化感水稻PI312777和普通水稻辽粳9为试材,研究了田间稗草和水稻1∶1共生条件下,土壤微生物生物量碳及脱氢酶、脲酶和转化酶活性的变化.结果表明：在稗草 的干扰下,化感水稻PI312777根区土壤微生物生物量碳含量比单作减少了 50.52％（P<0.01）,而行间土壤微生物生物量碳含量增加;普通水稻辽粳9根区土壤 微生物生物量碳含量比单作减少了38.99％（P<0.01）,但其行间土壤微生物生物量碳含量无明显变化.两个水稻品种根区土壤脱氢酶活性均被显著抑制（P<0.05）,下降率都在20％以上;PI312777根区土壤脲酶和转化酶活性均被显著促进（P<0.01）;而辽粳9根区土壤转化酶活性也被显著抑制（P<0.01）,但脲酶活性无明显变化.化感水稻根区土壤微生物生物量碳含量的显著减少及脲酶、转化酶活性的增加是其化感特性的表现,表明土壤微生物和酶均参与了水稻和稗草的种间作用,化感水稻具有抗稗草干扰的明显优势.     

Soil oxidases recovered faster than hydrolases in a 50-year chronosequence of desert revegetation

Aims

Desert characterized by alkaline soil with low organic matter and nutrients has a high soil oxidative potential. We hypothesized that oxidase activities would recover faster than hydrolases during the succession of sand-fixing community.

Methods

Sand dunes stabilized in different years, including a moving sand dune and a steppe at the southeastern fringe of the Tengger Desert, were selected to investigate restoration of extracellular enzyme activities (EEAs) in a 50-year chronosequence.

Results

Oxidases showed significantly higher activities than hydrolases at all ten studied sites and EEAs exibited a decreasing trend from catalase, phenol oxidase, sucrase, urease, alkaline phosphatase, α-Amylase to cellulase. After 50 years of revegetation, most EEAs in topsoil recovered to 50–83% of that of the steppe except for urease. Oxidase activities recovered earlier and faster than hydrolases, while hydrolases activities attained the fastest recovery at 19–25 years in the 50-year chronosequence.

Conclusions

Recovery of EEAs was modulated by the succession of the sand-fixed community: oxidases activities exhibited peak recovery rates at the stage when shrubs dominated the community, while recovery of hydrolases activities appeared to be mainly regulated by biological soil crusts and annual plants.     

Miscanthus × giganteus and Arundo donax shoot and rhizome tolerance of extreme moisture stress

Crops grown for bioenergy production are a mandated component of the United States energy portfolio. Giant miscanthus (Miscanthus × giganteus) is a leading bioenergy crop similar in habit to the invasive plant giant reed (Arundo donax). To characterize the environmental tolerance of giant miscanthus, we compared the soil moisture stress tolerance of giant miscanthus and giant reed under glasshouse conditions. We subjected both species to soil moisture conditions of severe drought (?4.2 MPa), mild drought (?0.5 MPa), field‐capacity (control), and flooded soils. These conditions were applied to two cohorts: one in which soil moisture conditions were imposed on newly planted rhizome fragments, and one in which conditions were imposed on established plants after 8 weeks of growth in field‐capacity soil. After 16 weeks, we harvested all plants, measured above‐ and belowground biomass, and evaluated the reproductive viability of rhizome fragments. The total biomass of each species under flooded conditions was not different from the field‐capacity control groups regardless of cohort. However, drought did affect the two cohorts differently. In the cohort treated after 8 weeks of growth, mild and severe drought conditions resulted in 56% and 66% reductions in biomass, averaged over both species, compared with the controls. In the cohort treated for the entire 16 weeks, mild and severe drought conditions resulted in 92% and 94% reductions in biomass. Rhizome fragments from both species and both cohorts showed 100% viability following flooded and control treatments; drought treatments reduced rhizome viability in both species, with a greater impact on giant miscanthus. Although giant miscanthus does not appear to have the potential to escape and establish in relatively dry upland ecosystems, it does show tolerance to flooded conditions similar to giant reed.     

洞庭湖区退田还湖后不同恢复模式下土壤酶活性的变化

以洞庭湖区退田还湖后不同恢复模式下(恢复自然水域、种植芦苇、种植杨树)的典型堤垸（青山垸、官垸和小集成）为研究对象,通过与相邻堤垸农田生态系统（水田、旱田）土壤中蔗糖酶、脲酶、磷酸酶和过氧化氢酶活性的比较,揭示不同退田还湖模式下土壤酶活性的变化及其与土壤化学特性的相关关系.结果表明：与水田、旱田相比,在表层土壤中,以种植杨树为恢复方式的小集成样地的过氧化氢酶活性显著增加,其他酶活性无显著变化;以种植芦苇为恢复方式的官垸样地的蔗糖酶和磷酸酶活性有所下降,其他酶活性无显著变化;恢复自然水域的青山垸样地中,除磷酸酶活性下降外,其他酶活性没有表现出明显的差异性.相关分析表明,土壤有机质含量与4种酶活性均表现出显著的正相关关系（P<0.01）,说明退田还湖后系统恢复模式导致的土壤有机质含量的变化是土壤酶活性变化的主要原因.     

鸡粪改良铜尾矿对3种豆科植物生长及基质微生物量和酶活性的影响

基质改良和耐性植物种选择是重金属矿业废弃地人工生态恢复的关键。通过室内盆栽试验研究不同比例腐熟鸡粪改良铜尾矿后对3种豆科植物决明(Cassia tora)、田菁(Sesbania cannabina)、菽麻(Crotalaria juncea)生长和尾矿基质中土壤微生物量C、N及过氧化氢酶、碱性磷酸酶、脲酶和脱氢酶活性的影响。结果表明:添加鸡粪改良处理后3种植物茎叶生物量、根系生物量和体内总磷含量均有提高,植物体内总氮含量则只有菽麻明显增加。添加鸡粪可提高尾矿基质中微生物量C以及脲酶和脱氢酶活性,其中菽麻生长的尾矿基质中微生物量C含量增加最显著。尾矿基质中微生物量C与基质中总氮、有效磷呈显著正相关,菽麻生长的尾矿基质中微生物量C与基质中有效态Cu、Zn呈显著负相关。田菁、菽麻生长的尾矿基质中脲酶、脱氢酶与基质中总氮、有效磷呈显著正相关,决明、菽麻生长的尾矿基质中脱氢酶与基质中微生物量C呈显著正相关,决明生长的尾矿基质中脲酶、脱氢酶与基质中有效态Zn呈显著负相关。综合分析表明,铜尾矿∶鸡粪=250∶1的处理方式可作为鸡粪改良铜尾矿基质较好的一种比例模式,该处理方式下菽麻可作为铜尾矿生态修复优选植物种。     

种植转Bt基因抗虫棉对土壤生物学活性的影响

采用温室盆栽实验,研究了种植转Bt基因棉（苏抗103）和同源常规棉（苏棉12）对根际土壤生物学活性的影响。结果表明：与对照常规棉相比,种植转Bt基因棉对根际土壤脱氢酶、碱性磷酸酶、蔗糖酶和土壤呼吸的影响因生育期而异,土壤脲酶、蛋白酶和微生物量C在各生育期均没有显著差异;土壤蔗糖酶、土壤脱氢酶和土壤呼吸分别只在苗期（苏抗103〉苏棉12,增幅为25．5％）、花铃期（苏抗103〉苏棉12,增幅为21．6％）、花铃期（苏抗103〉苏棉12,增幅为36．1％）存在显著差异;土壤磷酸酶在花铃期和吐絮期活性显著下降（降幅分别为22．1％和32．9％）。