沼液淹没土壤抑制根结线虫及对土壤线虫群落的影响     

李钰飞  刘本生  许俊香  李吉进  郎乾乾  乔玉辉  孙钦平 《中国生态农业学报》2020,28(8):1249-1257

为探索沼液抑制根结线虫的效果,本研究通过盆栽试验,以番茄为试供作物,对比了种植前沼液淹没土壤(BSS)、种植期间浇灌沼液(BS)和加热(HE)3种方法对根结线虫的防控效果。结果表明,与不采取任何措施的对照(CK)处理相比, BSS处理抑制根结线虫效果最为明显,防效高达97.1%,根结指数分别比HE和BS处理降低96.9%和92.9%。HE处理尽管在处理土壤后显著降低了根结线虫数量,但在最后破坏性取样时(结束试验)出现反弹,根结线虫数量甚至高于CK处理。对于土壤线虫群落,CK处理中以植食性线虫为主(81.8%);两个沼液处理中食细菌线虫占优势(平均78.3%),且其中的杂食捕食性线虫在土壤前处理后消失,在试验结束时又重新出现,但所占比例依然非常低。沼液淹水方式的高效防控效果揭示了利用沼液防控根结线虫的关键期在于线虫入侵到植物根部之前的幼虫期。然而,在盆栽系统中,沼液淹水的方式也对作物生长表现出了一定的抑制趋势。高量沼液施用防控病害的同时引发的植物毒害作用以及环境污染风险,需要进一步开展田间研究。  相似文献   

菌剂挂膜3D-RBC联合BCO工艺处理养猪沼液废水     

刘向阳  张千  罗万东  陈雪  张正义  郭青松  赵天涛 《农业工程学报》2020,36(20):49-56

针对养猪沼液废水寡营养、高氨氮的水质特征,该研究采用耐高氨氮、适应贫营养生长的异养硝化-好氧反硝化（Heterotrophic Nitrification-Aerobic Denitrification,以下简称HN-AD）菌挂膜启动三维结构生物转盘+生物接触氧化反应器（3D-RBC+BCO）组合工艺对沼液进行处理。该文研究了3D-RBC+BCO组合工艺在真实沼液条件下的启动过程及污染物去除效果,重点考察了溶解氧（Dissolved Oxygen,DO）浓度和C/N比2个关键因素对组合工艺污染物去除效果的影响。同时,借助高通量测序技术对DO和C/N比优化过程中微生物群落结构的变化规律进行解析。结果表明：在真实沼液条件下,采用HN-AD菌剂挂膜启动方法,仅用12和18 d就分别完成3D-RBC和BCO反应器的挂膜启动,同时组合工艺对COD、NH4+-N和TN的去除率分别稳定在94.8%、95.7%和80.1%,出水优于城镇污水厂排放一级B标准。在对3D-RBC反应器DO和C/N比的优化过程中,增设底曝后COD、NH4+-N和TN等指标的去除率分别降低了25.4%、15.4%和15.5%。高通量测序结果显示,增加底曝后3D-RBC盘片生物膜中微生物菌属的数量小幅下降,但HN-AD优势菌属的种类与丰度显著降低,导致脱氮效率下降;贫营养型Acinetobacter、Pseudomonas菌属是3D-RBC可以对真实沼液高效脱氮的关键,提高C/N比会显著降低其丰度,进而影响脱氮效果。  相似文献   

Soil microbial communities resistant to changes in plant functional group composition     

Carolyn B. Marshall  Roy Turkington 《Soil biology & biochemistry》2011,43(1):78-85

The soil community is an often ignored part of research which links plant biodiversity and ecosystem functioning despite their influence on numerous functions such as decomposition and nutrient cycling. Few consistent patterns have been detected that link plant and soil community composition. We used a removal experiment in a northern Canadian grassland to examine the effects of plant functional group identity on soil microbial community structure and function. Plant functional groups (graminoids, legumes and forbs) were removed independently from plots for five growing seasons (2003-2007) and in the fifth year effects on the soil microbial community were examined using substrate-induced respiration (SIR - a measure of metabolic diversity) and phospholipid fatty acid analysis (PLFA - a measure of microbial community composition). Removal treatments were also crossed with both a fertilizer treatment and a fungicide treatment to determine if effects of functional group identity on the soil community were context dependent. Plant functional group identity had almost no effect on the soil microbial community as measured by either SIR or PLFA. Likewise, soil properties including total carbon, pH, moisture and nutrients showed a limited response to plant removals in the fifth year after removals. We found a direct effect of fertilizer on the soil community, with fertilized plots having decreased metabolic diversity, with a decreased ability to metabolize amino acids and a phenolic acid, but there was no direct soil microbial response to fungicide. We show that in this northern Canadian grassland the soil microbial community is relatively insensitive to changes in plant functional group composition, and suggest that in northern ecosystems, where plant material is only slowly incorporated into the soil, five growing seasons may be insufficient to detect the impact of a changing plant community on the soil microbes.  相似文献   

Land-use history has a stronger impact on soil microbial community composition than aboveground vegetation and soil properties     

Kamlesh Jangid  Mark A. Williams  Thomas M. Schmidt  William B. Whitman 《Soil biology & biochemistry》2011,43(10):2184-2193

The response of soil microbial communities following changes in land-use is governed by multiple factors. The objectives of this study were to investigate (i) whether soil microbial communities track the changes in aboveground vegetation during succession; and (ii) whether microbial communities return to their native state over time. Two successional gradients with different vegetation were studied at the W. K. Kellogg Biological Station, Michigan. The first gradient comprised a conventionally tilled cropland (CT), mid-succession forest (SF) abandoned from cultivation prior to 1951, and native deciduous forest (DF). The second gradient comprised the CT cropland, early-succession grassland (ES) restored in 1989, and long-term mowed grassland (MG). With succession, the total microbial PLFAs and soil microbial biomass C consistently increased in both gradients. While bacterial rRNA gene diversity remained unchanged, the abundance and composition of many bacterial phyla changed significantly. Moreover, microbial communities in the relatively pristine DF and MG soils were very similar despite major differences in soil properties and vegetation. After >50 years of succession, and despite different vegetation, microbial communities in SF were more similar to those in mature DF than in CT. In contrast, even after 17 years of succession, microbial communities in ES were more similar to CT than endpoint MG despite very different vegetation between CT and ES. This result suggested a lasting impact of cultivation history on the soil microbial community. With conversion of deciduous to conifer forest (CF), there was a significant change in multiple soil properties that correlated with changes in microbial biomass, rRNA gene diversity and community composition. In conclusion, history of land-use was a stronger determinant of the composition of microbial communities than vegetation and soil properties. Further, microbial communities in disturbed soils apparently return to their native state with time.  相似文献   

不同处理方式对奶牛粪细菌群落多样性及群落结构的影响     

郑金伟  李辉信  胡锋 《农业环境保护》2009,(3):555-558

以腐熟牛粪、新鲜牛粪以及蚯蚓粪为材料,提取其微生物总DNA,利用细菌16SrDNAV3区扩增及变性梯度凝胶电泳（PCR-DGGE）法,分析了3种材料中细菌的多样性以及细菌群落结构的相似性。结果表明,蚯蚓粪的细菌多样性最丰富,腐熟牛粪次之,新鲜牛粪的细菌多样性最小。蚯蚓粪和腐熟牛粪的细菌群落结构有40%的相似性;蚯蚓粪和新鲜牛粪的细菌群落结构的相似性为25%;新鲜牛粪和腐熟牛粪的细菌群落结构的相似性则为35%。  相似文献   

甘肃徽县铅锌污染农业区冬季土壤纤毛虫群落特征     

马正学  贺鹏辉  秦洁  宁应之 《农业环境保护》2009,(6):1127-1135

2006年10月至2008年5月,用活体观察和固定染色方法对甘肃省徽县铅锌污染农业区土壤中纤毛虫冬季的群落特征进行了研究。在5 个样点中共鉴定到土壤纤毛虫75 种（包括9个未定名种和3个国内新记录种）,隶属于3纲、11目、30科、41属;对照1 、对照2 、厂区、县城和牟坝各样点的土壤中分别有纤毛虫42 、39、17、16和28 种;对照样点与受污染较重的厂区、县城和牟坝土壤中纤毛虫群落相似性系数为极不相似（q=0.14、0.22、0.27之间）;各样点的物种多样性指数分别为4.76、4.28、2.15、2.05和3.28;各样点的铅含量分别为211、182、490、427和434 mg·kg^-1,锌含量分别为48.4、46.8、1 194、166和392 mg·kg^-1。结果表明,铅锌污染对农业土壤纤毛虫群落有很大影响,主要体现在群落结构趋于简单化,物种多样性明显下降。  相似文献   

淹水培养过程中水稻土地杆菌科微生物群落结构变化特征     

拓晓骅  朱辉  王保莉  曲东 《农业环境保护》2012,(6):1165-1171

采用淹水非种植水稻土微环境模式系统,对水稻土进行1 h和1、5、10、20、30 d淹水培养,利用PCR-DGGE技术检测、多元统计分析淹水培养过程中地杆菌科微生物的群落结构和多样性变化规律及其影响因子。结果表明,淹水培养过程中地杆菌科微生物群落结构发生了明显的演替性变化：由r-对策优势种群演替至k-对策优势种群,且群落结构由不稳定向稳定演变（培养1 h和1 d处理间相似性最低,群落结构变化最大,20 d和30 d处理间相似性最高,群落结构变化最小）;该过程中,地杆菌科微生物物种丰富度指数和Shannon-Weiner指数在1 h处理中均为最小,5 d处理的最大;CCA相关性分析表明,淹水培养过程中Fe（Ⅱ）浓度与群落结构多样性指数呈正相关,证实该类微生物对于异化铁还原能力具有重要作用;测序结果表明,19个优势DGGE条带与来自水稻土中的未培养地杆菌科微生物亲缘关系相近。  相似文献   

陕北黄土丘陵区退耕地植物群落演替特征     

刘宝军  赵晓光  党小虎  王国梁  袁子成 《中国水土保持科学》2012,10(5):77-83

为了解黄土丘陵区侵蚀地貌退耕地植物群落演替模式及其基本特征,以陕北安塞纸坊沟流域的20块不同年限退耕地和荒坡为研究对象,采用空间代替时间序列的方法进行植物群落的调查和演替特征的分析。结果表明:退耕地植物群落大致经历了茵陈蒿群落—杂类草—狗尾草群落—长芒草群落—铁杆蒿群落—茭蒿群落的演替过程。植物群落的Shannon-Wiener指数、Simpson多样性指数、Margalef丰富度指数和Pielou均匀度指数均表现出随演替进行而上升的变化规律,但上升的速率各异;演替前期和中期的群落基本上属于对数级数分布,说明该阶段的物种组成主要是生态位预占模式起作用,演替后期的群落属于对数正态分布,可能是生态位预占、周围繁殖体的侵入压力、种间竞争和其他因素共同作用的结果;群落盖度变化与演替时间符合二次函数变化规律。  相似文献   

苏北低山丘陵区典型森林生态脆弱性评价   总被引：2，自引：0，他引：2  

于法展  陈龙乾  沈正平  仇方道 《水土保持研究》2012,19(6):188-192

生态脆弱性评价是当前全球变化与可持续发展研究中的热点问题。以苏北低山丘陵区典型性森林植被为研究对象,通过层次分析法构建了适合苏北低山丘陵区典型性森林生态脆弱性评价指标体系,制定了生态脆弱性评价标准,并根据生态脆弱度将森林植被划分成5个不同的脆弱级别;最后通过加权综合法对该地区典型性森林群落生态脆弱性进行评价。结果表明:该地区典型性森林生态脆弱度排序为侧柏(75.92)>麻栎(54.95)>栓皮栎(53.61)>黑松(49.63)>刺槐(47.68)>黄连木(45.69)>黄檀(44.92)>赤松(43.34)。  相似文献   

土壤微生物群落结构对凋落物组成变化的响应   总被引：9，自引：0，他引：9  

陈法霖  郑华  欧阳志云  张凯  屠乃美 《土壤学报》2011,48(3):603-611

凋落物分解是陆地生态系统养分循环的关键过程,明确凋落物多样性如何影响土壤微生物群落构成和多度,继而潜在地改变凋落物分解的微生物学机制有助于认识生物多样性和森林生态系统功能的关系。通过小盆模拟试验,应用磷脂脂肪酸谱图的方法研究了我国南方红壤丘陵区典型物种马尾松和湿地松的凋落物分别与白栎和青冈的凋落物混合,与单一针叶凋落物分解时相比,针阔混合凋落物分解过程中土壤微生物群落结构的变化,结果显示:(1)针阔混合凋落物分解时土壤微生物群落磷脂脂肪酸(Phospholipidfatty acids,PLFA)总量低于单一针叶处理,细菌和放线菌的相对多度高于单一针叶处理,真菌则相反,群落真菌/细菌低于单一针叶处理,土壤微生物生物量的差异主要来自于真菌;(2)主成分分析表明:针阔混合凋落物分解与单一针叶凋落物分解的土壤微生物群落结构差异显著,两个时期(分解9个月和18个月)主成分一分别可以解释65.74%和89.63%的变异,第一主成分主要包括18∶2ω6,9、18∶1ω9c、17∶0和10Me18∶0等磷脂脂肪酸;(3)土壤微生物群落结构受凋落物初始C/N和木质素/N调控,土壤微生物群落细菌的相对多度与凋落物初始C/N和木质素/N显著负相关,真菌则与凋落物初始C/N和木质素/N显著正相关,群落真菌/细菌与凋落物初始C/N和木质素/N显著正相关。针阔凋落物混合分解通过改变凋落物C/N和木质素/N,提供了对分解者更为有利的微环境。  相似文献