威廉腔环蚓（Metaphire guillelmi）对~（14）C-土壤有机质转化的研究

土壤有机碳是全球碳循环的重要组成部分,而大型土壤动物对土壤碳库的稳定性起着重要的决定作用。利用14C示踪技术,以14C-葡萄糖制备微生物源的土壤有机质（Soil organic matter,SOM）,以蚯蚓威廉腔环蚓（Metaphire guillelmi）为代表,研究了14C-SOM在含有蚯蚓的两种土壤、不含蚯蚓的对照土壤和不含蚯蚓的蚓粪中的矿化、残留物在土壤和蚓粪中分布以及蚯蚓对14C-SOM的吸收。结果显示,15 d的培育期内蚯蚓显著加快了14C-SOM的矿化,在土壤中的矿化量是不含蚯蚓的对照土壤中矿化量的1.5～1.7倍,然而当移出蚯蚓后,残留14C-SOM在两种土壤中40 d内的矿化都比对照土壤中低。大约有4.2%～4.8%的14C-SOM被蚯蚓吸收利用。在有蚯蚓存在的土壤中,14C-SOM残留物在胡敏素中的含量有所增高,而在溶解有机物（DOM）中的含量显著降低。14C-SOM在不含蚯蚓的蚓粪中55 d内的矿化量和矿化动力学以及残留分布与在对照土壤中均没有显著区别。这些结果表明,蚯蚓对微生物源14C-SOM转化的影响主要是蚯蚓的肠道作用,这种作用可表现在两个方面,即初期对14C-SOM矿化的促进作用以及后期对14C-SOM残留物的稳定化作用。后续工作中应进一步研究蚯蚓对其它来源SOM降解和转化的作用,阐明蚯蚓对SOM稳定性的控制机理,对揭示全球碳循环规律具有重要的意义。     

近地面O_3含量升高条件下土壤中腐殖质单体儿茶酚转化的放射性~（14）C示踪研究

近地面大气臭氧（O3）含量不断升高对生态环境的影响已引起人们的广泛关注,然而O3含量升高对土壤有机碳的矿化及转化影响却少有研究。土壤有机碳是全球碳循环的重要组成部分,土壤碳库的微小变化将引起大气CO2浓度的显著改变。文章以典型土壤腐殖质单体化合物儿茶酚为代表,利用14C示踪技术,研究了O3含量比当前背景升高约0.15μmol·mol-1时对土壤中腐殖质苯酚类前体化合物的矿化及转化的影响。结果表明,O3含量升高会对土壤中培育12d后儿茶酚的矿化及残留物分布具有显著的影响,而且这种影响程度和规律同土壤有关。O3含量升高促进了黄棕壤中儿茶酚的矿化,增加了儿茶酚残留物在黄棕壤腐殖酸（HA）中的总量,并使残留物在HA中偏向于同大分子结合。O3含量升高对灰潮土中儿茶酚的矿化有抑制作用,但对儿茶酚残留在HA内总量及分布没有显著影响。O3含量升高对儿茶酚在土壤中的稳定性及归趋的影响可能是O3对于微生物活性的抑制作用和O3的直接氧化作用的共同结果。后续工作中应研究土壤腐殖质中其它组份的稳定性及转化对近地面大气O3含量升高的响应,以全面考察O3含量升高对土壤碳库的影响。     

秸秆不同还田方式下蚯蚓对旱作稻田土壤碳、氮的影响

通过两年的田间小区试验，研究了在秸秆的不同施用方式下，蚯蚓(Pheretima sp)对旱作水稻土壤中碳、氮的影响。设置5个处理：秸秆混施，秸秆深施 蚯蚓，秸秆表施，秸秆表施 蚯蚓，对照。2001年夏季播种旱稻，在4个主要生育期采集(0-20cm)土样。2002年再次播种该品种旱稻，采集成熟期(0-20cm)土壤。测定土壤碳、氮以及微生物量碳、氮。结果表明，不论采用何种秸秆还田方式，蚯蚓并不造成土壤有机碳和全氮显著耗减。蚯蚓活动对土壤氨态氮及硝态氮的影响较大；从总体上看，它促进了土壤氮的矿化。不同秸秆施用方式都影响蚯蚓对土壤微生物的作用，在表施秸秆情况下，蚯蚓对微生物量提高最显著。     

蚯蚓和堆肥固定化添加模式对漆酶降解土壤五氯酚的影响

利用土壤五氯酚（PCP）污染模拟实验,研究两种不同生态型蚯蚓（赤子爱胜蚓Eisenia foetida和壮尾环毛蚓Amynthas robustus E.Perrie）和堆肥固定化添加模式对漆酶降解土壤PCP的影响。在42 d培养期内,测试了不同处理下PCP质量分数、漆酶活性,以及土壤呼吸和微生物碳氮等微生物指标。结果表明：堆肥固定化漆酶降解土壤PCP的效果优于壳聚糖固定化漆酶和自由漆酶,主要原因是堆肥固定化漆酶能够有效地提高漆酶稳定性,减缓其活性下降速度。此外,堆肥还能提高土壤微生物的数量与活性,显著提升土壤漆酶的活性。添加两种生态型蚯蚓对漆酶活性影响不显著,但均可以显著提高土壤微生物的数量与活性,加速土壤中PCP的降解。壮尾环毛蚓对土壤微生物数量与活性的提升效果优于赤子爱胜蚓。     

氮沉降增加对原始阔叶红松林蚯蚓种类和数量的影响

氮沉降是影响陆地生源要素生物地球化学循环的主要环境因子之一。以往对凋落物和土壤有机碳降解过程中分解者的作用研究主要集中在微生物方面,而对土壤动物蚯蚓的研究较少。对中国长白山阔叶红松林林地施氮处理6年,施氮量为背景条件下增加N 50 kg·hm~(-2)·a-1,运用手捡法和方形土壤采样器对森林覆盖层和土壤矿质层中蚯蚓种类和数量进行了调查,并采用元素分析仪测定了凋落物和土壤层中的有机碳氮含量。结果显示,在对照和施氮样地,蚯蚓的种类和密度分布模式相似,共观察到4种类型的蚯蚓,分别是表栖类的赤子爱胜蚓(Eiseniafoetida)和环毛蚓(Pheretima sp.)、内栖类和深土栖类的长白山杜拉蚓(Drawidachangbaiensis)及蚯蚓的幼虫线蚓(Enchytraeidae spp.)。其中,Eiseniafoetida种类的密度最大,可以达到25 individuals·m~(-2),其次为Drawidachangbaiensis种类,其密度可达到6 individuals·m~(-2),Pheretima sp.的密度最小,甚至在本次调查的施氮样地并未发现该类蚯蚓。3种功能群在两个处理中总的密度分别为对照样地23 individuals·m~(-2)、施氮样地为31 individuals·m~(-2),长白山阔叶红松林对照和施氮土壤中蚯蚓的种类和密度没有明显差异(P=0.238)。在调查的4个层位中,总碳并未受到氮添加的影响,同时,总氮也并未呈现出显著的变化,这与蚯蚓的研究结果一致。该研究可为氮沉降对森林生态系统的影响的进一步研究提供参考。     

蚯蚓粪肥输入促进水稻土有机磷矿化的机制研究

采用盆栽试验,以小白菜(Brassica chinensis L.)为试验作物,设置4个蚯蚓粪肥处理,分别为对照(CK,0 g·kg~(-1))、低量(A1,40 g·kg~(-1))、中量(A2,80 g·kg~(-1))、高量(A3,120 g·kg~(-1)),每个处理4次重复,于小白菜移栽后0、7、14、21d和35d采集土壤样品并测定各指标,研究蚯蚓粪肥对水稻土有机磷矿化以及微生物活性的影响。结果表明,(1)蚯蚓粪肥对小白菜根际土和非根际土微生物生物量碳、微生物生物量磷均有显著影响(P0.05),各处理组中非根际土微生物生物量碳磷比均低于根际土1.9-2.0倍。(2)培养期间,蚯蚓粪肥处理的水稻土酸性磷酸酶活性、有效磷及各磷形态含量相比对照组均有显著性提高。(3)处理组土壤各指标相关性分析结果表明:土壤微生物生物量磷、酸性磷酸酶活性均与中稳定性有机磷Na OH-P_o存在显著负相关关系;在A2和A3水平下,微生物生物量磷与活性有机磷Na HCO_3-P_o之间存在显著负相关关系,Na HCO_3-P_o与Na OH-P_o存在显著正相关关系,稳定态有机磷C.HCl-P_o与Na OH-P_o、Na HCO_3-P_o均呈显著负相关关系。研究表明,蚯蚓粪肥极显著提高土壤NaOH-P_o含量和酸性磷酸酶活性,有效促进Na OH-P_o活化的同时提高了微生物对磷的贮存,其中非根际土微生物对磷的固定强于根际土;蚯蚓粪肥在加速土壤Na HCO_3-P_o和Na OH-P_o矿化的同时也促进了C.HCl-P_o生成,其中微生物生物量磷对C.HCl-P_o的合成具有促进作用。     

鸭粪和环丙沙星对潮土微生物群落功能多样性的影响

为了评价鸭粪中残留的环丙沙星(ciprofloxacin,CIP)对土壤微生物群落功能多样性的影响,布置培养试验,设五个处理,分别是Ⅰ:CK(对照)、Ⅱ:CIP(人工添加的CIP)、Ⅲ:DF(添加不含抗生素的鸭粪)、Ⅳ:DF+CIP(在Ⅲ的基础上再外源添加CIP)、Ⅴ:DF(CIP)(粪源CIP即含有CIP的鸭粪),培养81 d。借助Biolog技术研究了不同来源的CIP对土壤微生物功能多样性的影响。结果表明,培养1 d后,反映土壤微生物活性的平均颜色变化率(AWCD)表现为DFDF+CIPDF(CIP)CKCIP,说明环丙沙星对土壤微生物活性具有一定的抑制作用,且随着培养时间的延长其抑制作用减弱;添加鸭粪显著增强了土壤微生物活性和群落功能多样性;与人工添加进鸭粪中的环丙沙星相比,粪源环丙沙星对微生物活性的抑制作用更强,并显著降低了土壤中利用碳源微生物的物种丰富度指数(H)、均匀度指数(E)、优势度指数(Ds)和碳源利用丰富度指数(S);在培养过程中,土壤微生物利用的主要碳源种类随培养时间延长有所变化,初期利用的主要是糖类、羧酸类、聚合物类、胺类以及氨基酸类,后期主要是糖类和羧酸类。     

长期施肥对红壤性水稻土活性碳的影响

在23年的长期田间定位试验区,研究了不同施肥对红壤性水稻土活性碳的影响。结果表明,在不施肥(CK)、无机肥(NPK)、有机肥(猪粪 紫云英绿肥)(OM)和无机肥与有机肥配施(NPKM)处理中,土壤微生物量碳含量、潜在可矿化碳含量和可溶性有机碳含量均随土层深度的增加而降低;不同施肥处理土壤微生物量碳含量、潜在可矿化碳含量和可溶性有机碳含量从高到低顺序都为:NPKM>OM>NPK>CK,长期施用肥料,特别是施有机肥与无机肥配施能提高土壤微生物量碳、潜在可矿化碳和可溶性有机碳含量,从而保持和提高土壤碳库质量。同施肥处理A层的土壤活性碳占土壤有机碳的比率显著大于P层;同施肥处理同发生层各土壤活性碳占土壤有机碳比率从高到低的顺序为:潜在可矿化碳的比率(R2)>微生物量碳的比率(R1)>可溶性有机碳的比率(R3);同施肥处理同发生层土壤活性碳占土壤有机碳比率R1、R2、R3大小顺序都为:NPKM>OM>NPK>CK。除P层微生物量碳和可溶性有机碳之间外,土壤有机碳总量与各活性碳之间以及各类活性碳之间相关性均达到极显著水平。     

利用餐厨和绿化垃圾提高蚯蚓堆肥效率处理剩余污泥的研究

为了显著提高蚯蚓堆肥处理剩余污泥的效率,在实验室条件下进行了掺入不同比例餐厨和绿化垃圾的剩余污泥蚯蚓堆肥试验。在保持剩余污泥占主体的情况下,试验按照剩余污泥：餐厨垃圾：绿化垃圾的质量比（干质量）顺序,共设6个不同配比处理组,分别为100/0/0、90/5/5、80/10/10、70/15/15、70/20/10和70/10/20,各组接种蚯蚓后恒温（25±1）℃暗室培养,中途适时补充基质和水分,试验为期7周。试验结束后,去除未被降解基质,分离并量测蚯蚓质量和数量以及蚓粪质量及其养分含量,并据此量化比较各组蚯蚓堆肥效率。试验结果表明,与纯污泥相比,增加餐厨和绿化垃圾的总比例可以显著加快蚯蚓的生长、成熟和繁殖速度,显著提高对应基质的降解速率和蚓粪生产速率,而且相应蚓粪的养分（总有机碳、全钾）含量也会显著增加（全氮和全磷含量无显著影响）。在保持剩余污泥占70%比例下,掺入15%餐厨垃圾和15%绿化垃圾的组别蚯蚓堆肥处理剩余污泥的效率达到最高（蚓粪的养分含量除外）,并与其他组别相比具有统计显著性。总之,餐厨和绿化垃圾的掺入能够显著提高蚯蚓堆肥处理剩余污泥的效率。     

川西北高寒草甸两种蚯蚓的互作及其对土壤养分的影响

以川西北高寒草甸中普遍存在的两种蚯蚓(微小双胸蚓Bimastus parvus和威廉腔蚓Metaphire guillemi)为研究对象,采用野外微宇宙实验方法比较单独接种和混合接种时两种蚯蚓的数量、分布和繁殖状况,以及牛粪分解率和土壤养分含量的变化,探讨不同蚯蚓种群间的相互作用及其对土壤养分的影响.结果发现:1)两种蚯蚓混合接种加快了牛粪分解,增加了下层(10~20 cm)土壤可溶性氮含量,但对牛粪分解速率和土壤可溶性氮含量均不存在交互作用;2)在混合接种处理中,微小双胸蚓的死亡比率显著高于威廉腔蚓的死亡比率;3)两种蚯蚓混合接种处理时,威廉腔蚓的繁殖明显受到抑制,而微小双胸蚓的幼蚓数量有所增加.研究表明,威廉腔蚓和微小双胸蚓共存能够发生竞争性相互作用,加快地面上的牛粪分解,增加土壤可溶性氮含量,从而可能提高高寒草甸的初级生产力.     

A simulation model to evaluate the impacts of invasive earthworms on soil carbon dynamics

Recent studies have reported that earthworm invasions alter native communities and impact nutrient cycling in terrestrial ecosystems. We developed a simulation model to evaluate the potential impacts of earthworm invasions on carbon dynamics, taking into consideration earthworm feeding strategies and priming effects on the microorganisms through their casting activities. Responses of carbon stocks (forest litter, soil organic matter, microbial biomass and earthworm populations) and carbon fluxes (litter decomposition, earthworm consumption, and microbial respiration) were used to evaluate an earthworm invasion of a forest ecosystem. Data from a northern temperate forest (Arnot Forest, New York) were adapted for model calibration and evaluation. Simulation results suggest that the impact and outcome of earthworm invasions are affected by pre-invasion resource availability (litter and soil organic matter), invasive earthworm assemblages (particularly feeding strategy), and invasion history (associated with earthworm population dynamics). The abovementioned factors may also determine invasion progress of earthworm species. The accuracy of the model could be improved by the addition of environmental modules (e.g., soil water regimes), precise parameters accounting for individual species attributes under different environmental conditions (e.g. utilization ability of different types of food resources), as well as earthworm population dynamics (size and structure) and interactions with predators and other invasive/indigenous species during the invasion progress. Such an earthworm invasion model could provide valuable evaluation of the complicated responses of carbon dynamics to earthworm invasions in a range of forest ecosystems, particularly under global change scenarios.     

Cattle manure biochar and earthworm interactively affected CO2 and N2O emissions in agricultural and forest soils: Observation of a distinct difference

• Earthworms increase CO₂ and N₂O emissions in agricultural and forest soil. • 10% biochar suppresses CO₂ and N₂O emissions in forest soil. • Biochar interacted with earthworm to significant affect CO₂ and N₂O emissions. The application of manure-derived biochar offers an alternative to avoid the direct application of manure to soil causing greenhouse gas emission. Soil fauna, especially earthworms, can markedly stimulate carbon dioxide (CO₂) and nitrous oxide (N₂O) emissions from soil. This study therefore investigated the effect of cattle manure biochar (added at rates of 0, 2%, or 10%, coded as BC0, BC2 and BC10, respectively) application, with or without earthworm Aporrectodea turgida, on emissions of CO₂ and N₂O and changes of physic-chemical properties of agricultural and forest soils in a laboratory incubation experiment. The BC10 treatment significantly enhanced cumulative CO₂ emissions by 27.9% relative to the untreated control in the agricultural soil. On the contrary, the BC2 and BC10 treatments significantly reduced cumulative CO₂ emissions by 16.3%–61.1% and N₂O emissions by 92.9%–95.1% compared to the untreated control in the forest soil. The addition of earthworm alone significantly enhanced the cumulative CO₂ and N₂O fluxes in agricultural and forest soils. Cumulative CO₂ and N₂O fluxes were significantly increased when BC2 and BC10 were applied with earthworm in the agricultural soil, but were significantly reduced when BC10 was applied with earthworm in the forest soil. Our study demonstrated that biochar application interacted with earthworm to affect CO₂ and N₂O emissions, which were also dependent on the soil type involved. Our study suggests that manure biochar application rate and use of earthworm need to be carefully studied for specific soil types to maximize the climate change mitigation potential of such management practices.     

Pesticide effects on microbial population and soil enzyme activities during vermicomposting of agricultural waste

The effects of different pesticides (propiconazole, profenofos, pretilachlor) on vermicomposting were evaluated for the adverse effects on soil enzyme activities (dehydrogenase, phosphatase, urease) and total microbial counts (TMC). There were remarkable increase in enzyme activities and TMC in presence of earthworm compared to control (earthworm absent). In comparison to control, the activities of phosphatase, dehydrogenase and urease in presence of vermicompost increased upto 30, 128 and 31.3% respectively; whereas increase of TMC was 71.9%. But, in presence of each of the pesticide, said activities decreased. Maximum inhibition of soil phosphatase activity (46.6%) was observed in presence of propiconazole (100 mg kg(-1)) after 120 days. Profenofos affected the soil dehydrogenase activity in the tune of 47% at 1000 mg kg(-1) concentration after 80 days and thereafter, the extent of toxicity decreased little. Soil urease activity was affected markedly in presence of profenofos and was 62% at 1000 mg kg(-1) level after 80 days. TMC also declined in presence of profenofos and pretilachlor. Increase in TMC was about 71.9% compared to control and the inhibition was more or less 60% when profenofos (1000 mg kg(-1)) was present even after 120 days of treatment.     

Earthworms and in vitro physiologically-based extraction tests: complementary tools for a holistic approach towards understanding risk at arsenic-contaminated sites

The relationship of the total arsenic content of a soil and its bioaccumulation by earthworms (Lumbricus rubellus and Dendrodrilus rubidus) to the arsenic fraction bioaccessible to humans, measured using an in vitro physiologically-based extraction test (PBET), was investigated. Soil and earthworm samples were collected at 24 sites at the former arsenic mine at the Devon Great Consols (DGC) in southwest England (UK), along with an uncontaminated site in Nottingham, UK, for comparison. Analysis of soil and earthworm total arsenic via inductively coupled plasma mass spectrometry (ICP-MS) was performed following a mixed acid digestion. Arsenic concentrations in the soil were elevated (204–9,025 mg kg⁻¹) at DGC. The arsenic bioaccumulation factor (BAF) for both earthworm species was found to correlate positively with the human bioaccessible fraction (HBF), although the correlation was only significant (P ≤ 0.05) for L. rubellus. The potential use of both in vitro PBETs and earthworms as complementary tools is explored as a holistic and multidisciplinary approach towards understanding risk at contaminated sites. Arsenic resistant earthworm species such as the L. rubellus populations at DGC are presented as a valuable tool for understanding risk at highly contaminated sites.     

全氟辛酸(PFOA)对蚯蚓的毒性作用

为考察全氟化合物的土壤生态毒性,以赤子爱胜蚓为模式生物,通过人工土壤染毒方法研究全氟辛酸(PFOA)对蚯蚓急性毒性、回避行为和SOD、CAT等抗氧化酶活性的影响。结果表明,PFOA对蚯蚓的急性毒性作用与染毒时间和染毒浓度相关,实验求得PFOA对蚯蚓毒性作用7和14d的LC50值分别为816.58和792.50mg·kg-1;蚯蚓在160mg·kg-1PFOA暴露浓度下表现出明显的回避反应。在10～120mg·kg-1PFOA长时间暴露下,蚯蚓体内SOD出现"低促高抑"的变化趋势,而GSH-Px则总体上被PFOA所抑制。     

污泥用作农肥处置及其环境影响

本文概述国内外污泥用作农肥处置的现状,全面分析了农田施用污泥产生的重金属积累,水处理凝聚剂及有害有机物的影响,过剩氮、磷的二次污染,恶臭及病原菌等问题,并提出相应的防治对策。加强管理,恰当处置,农田施用污泥是实现污泥资源化,解决污泥出路的好办法。     

蚯蚓粪复配硼钼调理剂对土壤改良和茄子生长的影响作用

土壤质量决定着农产品的质量和农业生产的可持续发展,然而土壤退化成为农业生产的重要限制因素之一,施用土壤调理剂有利于减缓土壤退化的速度.该研究配制土壤调理剂,即蚯蚓粪?草菇渣?蛭石=6?3?1、钼酸钠50 g·kg?1、硼酸13.3 g·kg?1,并设5个不同的处理CK、QY-T1、QY-T2、QY-T3、QY-T4,研...     

不同类型土壤中外源镍对赤子爱胜蚓的急性毒性

按照国际标准化组织(ISO)颁布的蚯蚓毒性试验方法,研究了镍离子在我国13种典型土壤中对赤子爱胜蚓(Eisenia fetida)的急性毒性,发现镍离子在不同类型土壤中对蚯蚓的半数致死浓度(LC50)变化范围为243.8-1970.6 mg·kg-1,镍离子在不同土壤中的毒性大小顺序为:湖南红壤＞重庆紫壤＞江西红壤＞河...     

Unexpected control of soil carbon turnover by soil carbon concentration

Soils are a key component of the terrestrial carbon cycle as they contain the majority of terrestrial carbon. Soil microorganisms mainly control the accumulation and loss of this carbon. However, traditional concepts of soil carbon stabilisation failed so far to account for environmental and energetic constraints of microorganisms. Here, we demonstrate for the first time that these biological limitations might have the overall control on soil carbon stability. In a long-term experiment, we incubated ¹³C-labelled compost with natural soils at various soil carbon concentrations. Unexpectedly, we found that soil carbon turnover decreased with lower carbon concentration. We developed a conceptual model that explained these observations. In this model, two types of particles were submitted to random walk movement in the soil profile: soil organic matter substrate and microbial decomposers. Soil carbon turnover depended only on the likelihood of a decomposer particle to meet a substrate particle; in consequence, carbon turnover decreased with lower carbon concentration, like observed in the experiment. This conceptual model was able to simulate realistic depth profiles of soil carbon and soil carbon age. Our results, which are simply based on the application of a two-step kinetic, unmystify the stability of soil carbon and suggest that observations like high carbon ages in subsoil, stability of carbon in fallows and priming of soil carbon might be simply explained by the probability to be decomposed.