扎龙自然保护区大型土壤动物的群落结构

在扎龙国家自然保护区,选择了羊草、星星草、寸草苔和芦苇4种群落,对大型土壤动物生态特征进行了研究。研究结果表明,在四种群落中,共获得大型土壤动物75类,4359只,隶属于3门、7纲、21目、50科。优势类群是蚁科、棘跳虫科。大型土壤动物的类群数:芦苇群落=星星草群落>羊草群落>寸草苔群落,个体数:芦苇群落>星星草群落>羊草群落>寸草苔群落,寸草苔群落的生境条件最差,大型土壤动物的水平分布具有不均匀性;大型土壤动物的垂直分布基本都随土层深度的增加而递减,表现出明显的表聚性。大型土壤动物的季节动态表现为,类群数:夏季>秋季>春季;个体数:夏季>秋季>春季,春季不论是类群数还是个体数都是最低的。大型土壤动物的多样性表现为,寸草苔群落=星星草群落>芦苇群落>羊草群落。     

不同退化阶段松嫩草地土壤对羊草种子萌发和幼苗生长的影响

在环境条件和人为因素的双重影响下,松嫩羊草草地发生了不同程度的退化演替。种子萌发和幼苗生长是植物生长和定植的关键生育期。为了明确不同退化草地土壤对羊草种子萌发和幼苗生长的影响,选取羊草(Leymus chinensis)群落、碱茅(Puccinellia distans)群落、虎尾草(Chloris virgata)群落和碱蓬(Suaeda glauca)群落作为4个草地退化演替阶段,研究了不同退化演替阶段的土壤对羊草种子萌发和幼苗生长特性的影响,探讨了不同退化阶段土壤理化性质与羊草种子萌发和幼苗生长的关系。结果表明:随着植被群落从羊草群落到虎尾草群落的退化演替进行,土壤p H值和电导率逐渐升高后趋于稳定,土壤碱化度越来越高,碱蓬群落土壤碱化度显著高于羊草群落;草地退化导致土壤养分含量逐渐减少,碱蓬群落土壤速效氮含量显著低于羊草群落。羊草种子在羊草群落土壤中的发芽率最高,随着土壤退化程度的加剧,羊草种子发芽率显著降低,羊草幼苗生长受到的抑制作用增强,退化土壤对羊草幼苗根长的生长抑制要比对幼苗苗长生长的抑制强。表明在一定程度上,羊草草地退化伴随着土壤盐碱化的发展,且随着土壤退化程度加剧,羊草萌发成苗受到的抑制作用越来越大。     

公路路域植被不同演替阶段土壤动物群落特征

通过对半干旱典型草原地带公路路域植被自然恢复过程中,即不同演替阶段的土壤动物群落研究表明,当原有的土壤—植被受到彻底破坏后,大型土壤动物也随之消失;中小型土壤动物对土壤—植被系统的依存程度要较大型土壤动物小得多,即便土壤—植被系统受到彻底破坏,中小型土壤动物也能存活。植被恢复阶段,土壤动物的类群和密度明显增加,植被发育顶级阶段两个生境的土壤动物类群和密度存在差异。植被恢复阶段和植被发育顶级阶段土壤动物的多样性差异较小。鞘翅目土壤动物与全部土壤动物的多样性指数变化趋势基本一致,鞘翅目土壤动物对研究区植被不同演替阶段具有明显的指示作用。土壤动物群落多样性指数与土壤pH、全磷、全钾和土壤自然含水量的平均灰色关联系数较大,说明在植被恢复过程中土壤动物群落多样性变化与这几个主要因子关系密切。     

章古台沙地人工林大型土壤动物群落特征

对章古台沙地典型人工林的大型土壤动物群落进行调查,共捕获大型土壤动物59类,1689只,隶属于2门4纲14目43科,优势类群为蚁科和金龟子科(幼虫),常见类群7类,稀有类群50类。不同人工林大型土壤动物的数量及种类组成差异很大,通常,群落的生境条件越优越,土壤动物的个体数量和种类越多。各群落土壤动物多样性指数排序为油松(2.5313)>小叶杨(2.3319)>樟子松(1.6423)>赤松(1.4651)。土壤动物的个体数量、种类、生物量及多样性指数具有较明显的时间动态变化。     

扎龙湿地苔藓群落土壤动物的分布及多样性

2007年4—5月份和2008年4—5月份,对扎龙湿地苔藓群落土壤动物进行了调查。通过对扎龙湿地苔藓群落土壤动物生态特征的研究,共捕获土壤动物22类、7384只,隶属于4门7纲17目25科;包括大型种类2788只,中小型种类4596只。优势类群为线虫纲、线蚓科和蚁科;常见类群有轮虫纲、鞘翅目、鞘翅目幼虫、蜱螨目、双翅目幼虫、疣跳虫科、盲蛛目。土壤动物的垂直分布表现出明显的表聚性;多样性的各项指数2007年均高于2008年,但2008年的种类和数量明显高于2007年。多样性指数与丰富度指数反映一致的变化规律;均匀性指数和优势度指数则表现不明显。     

刈割条件下松嫩平原碱化羊草草地土壤螨类群落变化特征的研究

应用类群属数、个体密度、多样性指数和MI指数等多个群落参数,研究刈割活动对松嫩平原碱化羊草草地土壤螨类群落特征的影响。本研究共捕获土壤螨类1 515只,分别隶属于3亚目61属。研究结果表明,刈割活动影响土壤螨类群落组成,其中主要是减少了隐气门亚目的个体数量;与围栏封育相比,刈割活动样地土壤螨类个体密度、群落多样性H′指数和丰富度SR指数显著下降,刈割活动明显降低土壤螨类群落结构的复杂程度和稳定性;土壤中气门亚目螨类群落结构样地间相比,刈割活动样地MI指数也显著减少,刈割活动限制了土壤捕食性螨类k选择类群比例的增长;此外,土壤甲螨群落MGP分析表明,两类处理样地间甲螨结构同样存在差异,其中刈割活动明显影响大孔低等甲螨的存在。     

南京方山生态公园不同人工植被土壤动物群落结构

2007年8月~10月采用大型改良干漏斗和手拣法对南京方山生态公园针阔混交林、茶园、农田等3种典型人工植被类型的土壤动物群落结构进行初步调查,共采得土壤动物样本1741个,隶属于3门9纲共25个类群。结果表明:蜱螨目(Acarina)、弹尾纲(Collembola)和线蚓科(Enchytraeidae)为3种人工植被生境的常年优势类群;等足目(Isopoda)、线虫纲(Nematoda)、双翅目(Diptera)和寡毛纲(Oligochaela)则为常年常见类群。土壤动物个体数量总数依次为茶园混交林农田;不同月份、不同植被类型以及不同月份与不同植被类型之间土壤动物群落的组成有所不同。多样性分析表明,类群多样性和丰富度指数茶园最高;均匀性指数茶园8月最高,10月农田最高。但三种人工植被类型土壤动物类群的丰富度、多样性指数、均匀性指数等无显著差异。土壤动物的类群垂直分布差异明显,类群数随土层向下逐步减少。     

拉萨半干旱河谷砂生槐灌丛不同封育时间土壤动物多样性特征

为了解半干旱河谷不同封育时间对砂生槐灌丛土壤动物群落组成及结构的影响,阐明土壤动物群落多样性及群落结构在高原灌丛植被恢复中的变化趋势,本研究对拉萨河中下游的不同封育时间砂生槐灌丛下土壤动物群落结构、垂直分布、多样性、土壤动物类群间的相关性特征进行分析。结果表明,砂生槐灌丛90份土样中共获得大中小型土壤动物491只,隶属3门9纲25类。优势种群为弹尾目、鞘翅目和蜱螨目,分别占类群总数的42.7%、15.9%和11.2%。土壤动物类群数和个体数量的垂直分布具有表聚性特征,多数土壤动物分布在0~20 cm土层,但因不同封育时间而有变化。封育10年样地0~10 cm土层土壤动物数量显著高于10~20和20~30 cm,该层土壤动物个体数占所有采集数的40.1%。随封育时间增加,植被盖度、土壤动物个体数量、类群数均呈逐渐上升趋势。土壤动物群落的多样性指数(H),均匀性指数(E),丰富度指数(D),优势度指数(I)和多群落间比较指数(DIC)基本随封育时间的增加逐渐增大,但DIC指数的最高值出现于封育10年和15年,分别为3.99和3.29,而未封育(对照)、封育4年和8年分别为0.66、0.49和0.63。不同封育时间半干旱河谷砂生槐灌丛螨类(A)/跳虫(C)值也呈现较大变异,封育4年的A/C值为2.67,高于其它封育时间,因此,A/C可作为拉萨半干旱河谷植被退化恢复演替评价的生物指示剂,这为高原生态环境状况评价提供参考依据。     

大兴安岭北部森林生态系统土壤动物组成与多样性分析

对大兴安岭北部7个代表性森林群落土壤动物进行调查,共捕获湿生土壤动物20216只,大、中小型土壤动物87类,19577只,隶属于4门9纲23目66科。大、中小型土壤动物的优势类群为螨类和节跳虫科,常见类群4类,两者占总捕获量的92.22%。各群落土壤动物的数量和种类组成有一定差异,其中杨落Ⅱ和白桦Ⅲ的数量和种类最多,柳草Ⅶ最少。7个群落共有类群23类,共优类群为螨类中的前气门亚目和中气门亚目,共有的常见类群2类:山跳虫科和线蚓科。7个群落间相似程度均较大,大多为中等相似。各群落土壤动物数量和种类在土壤各层的垂直分布上具有明显表聚性。在多样性分析中,各群落多样性指数H′大小为柳草Ⅶ>白桦Ⅲ>杨落Ⅱ>落沼Ⅳ>樟子松Ⅵ>桦杜Ⅰ>蒙古栎Ⅴ。大部分群落多样性指数的动态变化是8月>6月>10月。     

桂西北喀斯特不同植被演替阶段土壤微生物群落多样性

采用经典统计与排序分析方法,研究了桂西北喀斯特不同植被演替阶段(原生林、次生林、灌丛、草地)土壤微生物群落多样性变化特征,并探讨了土壤微生物群落多样性与土壤养分、土壤微生物生物量和土壤微生物数量之间的关系。结果表明:(1)桂西北喀斯特植被演替对土壤养分有较大的影响,除了土壤容重和全磷含量以外,由草地到原生林的演替过程中,土壤养分均呈显著的变化趋势(p0.05)。随着演替的进行,土壤pH值和容重逐渐减小。土壤有机碳、全氮、全钾、速效氮、速效磷和速效钾含量随着演替而逐渐增加趋势,其大小依次变现为原生林次生林灌丛草地,其中不同演替阶段土壤有机碳全氮、速效氮、速效磷和速效钾含量差异均显著(p0.05)。(2)土壤微生物量碳、氮、磷大小依次变现为原生林次生林灌丛草地,其中灌丛和次生林MBP含量差异不显著(p0.05)。MBC/MBN随着演替的进行呈逐渐减小趋势,MBC/MBP和MBN/MBP随着演替的进行呈逐渐增加趋势。(3)不同植被演替阶段土壤微生物数量及组成不同,其中以细菌数目最多,土壤微生物种群总数量、细菌和放线菌数目依次为原生林次生林灌丛草地。(4)不同演替阶段土壤微生物群落功能多样性指数存在一定差异,其中物种丰富度指数(H)、均匀度指数(E)和碳源利用丰富度指数(S)依次表现为原生林次生林灌丛草地(p0.05);而优势度指数(Ds)依次表现为原生林次生林灌丛草地,并且不同演替阶段优势度指数(Ds)差异不显著(p0.05)。(5)相关性分析表明土壤养分、土壤微生物量、土壤微生物数量均与土壤微生物群落多样性具有显著的相关性,其中,土壤微生物量对微生物群落多样性的贡献最大,而MBN,SOC和细菌数目是影响桂西北喀斯特不同植被演替阶段土壤微生物群落多样性分布的主要因子。     

营养和病虫害管理对双季杂交水稻种植系统的土壤生态质量的共同影响

The mineral fertilizers(NPK) and pesticide,including herbicides,insecticides and fungicides,were applied alone or in combination and the soil sampling was done at different growth stages during the crop cycle to study the changes in soil organic matter,microbial biomass and their activity parameters in a paddy soil with different nutrient and pest management practices in a hybrid rice double-cropping system.A consistent increase in the electron transport system(ETS) activity was measured during the different crop growth stages of rice.The use of fertilizers(NPK) alone or with pesticides increased ETS activity,while a decline of ETS activity was noticed with pesticides alone as compared with the control.Nearly an increasing trend in soil phenol content was observed with the progression of crop growthstages,while the usage of pesticides alone caused maximum increments in the soil phenol content.The soil protein content was found nearly stable with fertilizers and/or pesticides application at various growth stages in both crops taken.But notable changes were noticed at different growth stages probable because of fluctuations in moisture and temperature at particular stages,which might have their effects on N mineralization.Marked depletions in the phospholipid content were found with the advancement of crop growth stages,while the incorporation of fertilizers and/or pesticides also produced slight changes,in which a higher decline was noticed with pesticide application alone compared with the control.     

Effect of compost and chemical fertilizer on soil nematode community in a Chinese maize field

Nematode density and biodiversity in maize field soil treated with compost, chemical fertilizer and with no amendments were investigated in a multi-year field experiment at the Qu-Zhou experimental station, China Agricultural University. The soils were collected from the upper (0–20 cm) soil layer during the maize growing stages in 2004. The results demonstrated that significant differences for the total nematode density, bacterivores, fungivores, plant parasites and omnivores-predators density were found between treatments and between dates. The total nematode density and bacterivores density were greater in compost-treated soil than in chemical fertilizer-treated soil, and were greater in chemical fertilizer-treated soil than in control soil during all sampling periods. The total nematodes density ranged from 106 to 657 individuals per 100 g dry soil in the present study. Total 40 nematode genera were found in all treatments and sampling periods, and 12 genera were bacterivores, 4 genera were fungivores, 16 genera were plant parasites and 8 genera were omnivores-predators. Cephalobus, Rhabditis, Tylenchorhynchus, Pratylenchus, Helicotylenchus and Rotylenchus were dominant genera in present study. The plant parasites and bacterivores were dominant trophic groups. The ratio of bacterivores plus fungivores to plant parasites was higher in compost-treated soil compared to chemical fertilizer-treated soil except October. Maturity index and combined maturity index were lower in compost-treated soil compared to chemical fertilizer-treated and control soil except July. The plant parasite index was higher in compost-treated soil compared to chemical fertilizer-treated soil except July. The multi-year application of compost and chemical fertilizer had effected on soil nematode population density and community structure.     

苏南和赣东北低山区的森林土壤

在江苏省宁镇、宜溧和江西省东北部三个低山区,以20个代表性土壤剖面作典范变量分析,结果表明,在典范变量1、2构成的直角坐标平面上,按这三个低山区划分的4类土壤(基性岩发育的黄棕壤、普通黄棕壤、红黄壤、红壤),置信区间交叠,土壤个体之间的性质为连续变化、逐渐过渡。从中可见,各区内土壤个体都包括不同发育阶段的产物。参照中国土壤系统分类方案(1987),可把这三个低山区的土壤划归4纲7类中的8个亚类,土壤类型在总体上仍表现出从北向南逐渐由硅铝土过渡到铁铝土,以及每一地区由初育土逐渐过渡到成熟土的总趋势,但各亚类界线与三个地区的地理分界线并不完全重合。根据南京附近低山丘陵地区70个土壤剖面的数据,以及相应标准地上的林木生长状况,将上述各亚类再划分为共计10个土壤生态型。     

Earthworm communities in alluvial forests: Influence of altitude,vegetation stages and soil parameters

In many terrestrial ecosystems, soil parameters usually regulate the distribution of earthworm communities. In alluvial ecosystems, few studies have investigated the impact of periodic floods and alluvium deposition on soil fauna. In this context, we assumed that earthworm communities may vary depending on altitude (alpine, subalpine, mountain and hill levels), forest successional stage (post-pioneer to mature forests) and some soil parameters. Our results demonstrated that the composition of earthworm communities differed depending on altitudinal gradients. No earthworm was found at the alpine level while maximum density and biomass were observed at the hill level mainly due to the contribution of anecic species. A total of 27 species and subspecies were found over the three sampling sites, and Lumbricus moliboeus was discovered for the first time in carbonated soils. Soil texture had a major effect on epigeics that were often associated with coarse sandy texture in contrast to anecics which preferred deep soils and mature forest stages, which in combination provided the highest carbon content and the finest soil texture. In our study, carbonated fluviosols (Fluvisols according to the World Reference Base) were recorded; fluviosols typiques with well-structured A layers were generally found in mature or intermediate forest stages while most of fluviosols juveniles with heterogeneous texture were observed principally in post-pioneer forests. We conclude that in alluvial ecosystems, earthworm communities were highly dependent first on soil parameters, then altitude and to a lesser extent forest successional stages. Changes in earthworm communities tend to reflect a gradient of alluvial dynamics thus reinforcing the potential role of earthworms as bioindicators in natural and/or semi natural alluvial ecosystems.     

冬季作物对水稻生育期土壤微生物量碳、氮的影响

选取我国南方4种冬季作物黑麦草、紫云英、油菜、马铃薯,以冬闲田作对照,对水稻生育期土壤微生物量碳（SMBC）和土壤微生物量氮（SMBN）的短期内动态变化进行了研究。结果表明,早稻田翻耕前,冬季作物处理土壤SMBC和SMBN与冬闲田存在显著差异(P0.05),黑麦草处理SMBC为398.5 mg/kg,显著高于其他作物;紫云英处理SMBN最高,为97.8 mg/kg。在早稻整个生育期,黑麦草处理SMBC显著高于其他处理,晚稻生长过程中各处理无显著差异。冬季作物对稻田土壤微生物商(MQ)的影响,随着水稻生长发育进程有不同程度的变化,黑麦草处理在早稻整个生育期高于冬闲田。     

改良剂施用对重金属污染土壤溶液化学性质及豇豆生理特性的影响研究

本文研究了在不同生长时期凹凸棒土、硅藻土、泥炭、腐植酸对土壤重金属的钝化及豇豆生理特性的影响。结果表明:由于土壤的缓冲性,4种改良剂对土壤溶液pH影响较小;泥炭、腐植酸对Zn、Cu的钝化效果比凹凸棒土、硅藻土好,但4种改良剂对土壤溶液Pb和Cd浓度影响不明显;腐植酸、凹凸棒土均在不同程度上提高了豇豆叶片超氧化物歧化酶、过氧化物酶的活性,其中腐植酸的作用最为明显。除泥炭外,3种改良剂均使豇豆叶片的丙二醛、脯氨酸含量降低。受叶片衰老的影响,成熟期各改良剂对豇豆生理特性的作用不如苗期明显;冗余分析表明:4种改良剂对重金属的钝化效果依次为腐植酸、泥炭、凹凸棒土、硅藻土。本次试验结果说明有机物料腐植酸、泥炭可作为缓解豇豆重金属Zn、Cu胁迫的改良剂。     

缺硼对棉花不同品种苗期叶片POD、SOD同工酶的影响

在土培条件下 ,研究了 4个对缺硼反应不同的棉花品种苗期叶片中过氧化物酶 (POD)和超氧化物歧化酶 (SOD)同工酶。结果表明 ,缺硼使硼低效品种POD、SOD同工酶数量增加 ,而硼高效品种变化不明显 ,并推测新出现的几种同工酶与适应缺硼环境关系密切。不同生长时期 ,叶片POD、SOD同工酶谱不同 ,可能与不同时期对缺硼的适应能力不同有关。     

焉耆盆地白刺灌丛沙堆土壤理化性质

对焉耆盆地白刺灌丛沙堆不同演化阶段和沙堆间低地土壤理化性质进行分析。结果显示:（1）白刺灌丛沙堆不同演化阶段土壤粉砂、黏粒、有机质和养分含量均高于沙堆间低地,而土壤砂粒含量和pH值低于沙堆间低地;从白刺灌丛沙堆发育到稳定阶段,土壤砂粒含量和pH值逐渐降到最小值,而粉砂、黏粒、有机质和养分含量达到最高值,从白刺灌丛沙堆稳定到活化阶段,土壤砂粒含量和pH值急剧增加,而粉砂、黏粒、有机质和养分含量大幅度下降;（2）从整个剖面来看,由于白刺灌丛沙堆侵蚀和堆积的差异,随着深度的增加砂粒含量先减后增,而pH值、粉砂、黏粒、有机质和养分含量先增后减;0—15 cm土层砂粒含量最高,而15—45 cm土层最低;0—15 cm土层pH值、粉砂、黏粒、有机质和养分含量最低,而15—45 cm土层最高;（3）白刺灌丛沙堆发育和活化阶段强烈的吹蚀不利于有机质的积累,白刺灌丛沙堆稳定后为降尘截存、凋落物积累和微生物的繁殖提供有力的保障,表层黏粒得以截存和地衣状薄层结皮形成,增加土壤的有机质和养分含量。     

崇明东滩不同演替阶段湿地土壤有机碳汇聚能力的差异性及其微生物机制

旨在阐明崇明东滩不同演替阶段湿地土壤有机碳汇聚能力的差异性及其机制,以期为优化湿地的管理与保育措施,进而保持和提升湿地的碳汇功能提供理论指导和决策依据。研究结果表明,4个不同演替阶段湿地土壤有机碳含量和微生物呼吸强度有显著差异（P〈O．05）,中高潮滩处的土壤有机碳汇聚能力最高,这是由于其具有较高的有机碳输入（植物枯落物）和相对较低的碳输出（土壤呼吸）。PCR-DGGE分析和系统进化树结果表明,4个不同演替阶段土壤的微生物群落结构存在差异,一些特异性优势菌的存在可能是影响土壤微生物呼吸强度,并最终影响土壤有机碳汇聚能力的重要原因。出现在高潮滩的噬纤维菌和假单胞属菌具有较高降解纤维素等有机质的能力,它们的存在可能强化了高潮滩的土壤呼吸作用,从而降低了高潮滩土壤的有机碳汇聚能力。     

Studies on the survival of algae added to chemically treated soils—1. methodology

A modification of the method of Tchan (1952) for the direct enumeration of soil algae was evaluated with a view to determining effects of pesticides and herbicides upon soil algae. Modifications to Tchan's technique were the use of a Hg vapour u.v., light source for microscopy and a specially designed haemocytmeter slide. These modifications increased the intensity of fluorescence of algal cells, facilitated accurate estimation of numbers in soil as shown by high percentage recoveries of known numbers of algal cells added to sterile soil, and enabled transmitted or incident light systems to be used equally successfully.Using direct microscopy, various algal cells in culture were examined for fluorescence. Fluorescence during different stages of growth of two species of unicellular green algae was determined. Viable cells at all stages of growth were found to fluoresce. Newly killed cells, inactivated by heat, acid and herbicide treatment were found not to fluoresce. Twenty seven species of algae, selected for their wide range of structure and for their common occurrence in British soils were all found to fluoresce either in culture or when incubated in sterile soil.Four different (agronomic) soil types were examined for indigenous algae. To overcome seasonal variations that occur in numbers of algae, the effect of seeding soils with a mixed inoculum of algal cells was determined.The effects of shaking and ultra-sonicating soil suspensions before examination were compared in order to recover efficiently a known number of cells added to different soils. Survival of added algae in four soils of pH 5.8–7.8, and in one soil maintained at moisture contents ranging from 20–100% of the moisture holding capacity was determined. Growth of algae in soil at two different light intensities was also examined.