有效微生物菌在反刍动物生产中的研究与应用

文章介绍了有效微生物菌(EM)的组成及特点、研制及使用方式、作用机理、在反刍动物上的研究与应用及影响其作用效果的因素。     

土壤农药污染的微生物修复研究概况

总结了土壤农药污染的现状和危害、农药污染微生物修复的研究历程、农药污染微生物修复资源、农药污染微生物修复影响因素,展望了农药污染微生物修复前景,并分析了有待进一步研究的领域。     

三七根腐病病株和健株根域土壤微生态研究

对比三七健株和急性青枯型根腐病病株根域土壤微生物数目、土壤酶活性以及土壤养分,研究它们与根腐病间的关系。结果表明,病株根际土和根系的细菌数目显著大于健株,而放线菌和真菌数目小于健株;病株根际土和根系各微生物生理类群数目受外界环境影响发生了不同变化;健株非根际土的蔗糖酶、纤维素酶、过氧化氢酶和酸性磷酸酶活性均显著大于病株,但过氧化物酶和多酚氧化酶活性小于病株;非根际土壤放线菌和纤维素酶活性明显相关;病株非根际土的速效氮、磷、钾含量均高于健株,水溶性镁含量低于健株。病株根际土和根系微生态变化,特别是细菌数目的大量增加是急性青枯型根腐病最明显的特征。     

猪舍空气病原微生物与环境通风的关系研究进展

在介绍生猪生产环境控制因素的基础上,综述了猪舍空气中病原微生物种类、猪舍环境通风控制、评价方法、检测技术等方面的研究现状与进展,并对今后的研究方向进行了展望。     

Effect of different biofloc levels on microbial activity,water quality and performance of Litopenaeus vannamei in a tank system operated with no water exchange

In zero-exchange superintensive culture systems, flocculated particles (bioflocs) accumulate in the water column. Consequently, some control over the concentration of these particles must be performed. The objective of this study is to evaluate the effects of three concentrations of bioflocs on microbial activity, selected water quality indicators and performance of Litopenaeus vannamei in a tank system operated with no water exchange. A 44-day study was conducted with juvenile (6.8 g) shrimp stocked in twelve 850 L tanks at a stocking density of 459 shrimp m⁻³. Biofloc levels were expressed as three presets of total suspended solids (TSS) concentrations, as follows: 200 mg L⁻¹ (T200), 400–600 mg L⁻¹ (T400–600), and 800–1000 mg L⁻¹ (T800–1000). TSS levels were controlled by attaching a 40 L settling tank to each culture tank. Reduction of TSS to concentrations close to 200 mg L⁻¹ decreased the time of bacterial cell residence and significantly reduced the nitrification rates in the water (P < 0.05). The tanks in the T200 treatment had a greater variability of ammonia and nitrite (P < 0.05), which led to the need to increase the C:N ratio of the organic substrate to control ammonia through its assimilation into heterotrophic bacterial biomass. But the higher production of heterotrophic bacteria in T200 (P < 0.05) increased the dissolved oxygen demand. Nitrification rates were higher (P < 0.05) in tanks with TSS concentrations above 400 mg L⁻¹, and ammonia and nitrite were significantly lower than in the T200 tanks. We suggest that ammonia and nitrite in the T400–600 and T800–1000 tanks were controlled primarily by nitrifying bacteria, which provided higher stability of these parameters and of dissolved oxygen. Regarding shrimp performance, the reduction of TSS to levels close to 200 mg L⁻¹ was associated with better nutritional quality of bioflocs. Nevertheless, differences in biofloc levels and nutritional quality were not sufficient to affect the weight gain by shrimp. The rate of shrimp survival and the final shrimp biomass were lower (P < 0.05) when the TSS concentrations were higher than 800 mg L⁻¹. Analysis of the shrimps’ gills showed a higher degree of occlusion in the T800–1000 treatment (P < 0.05), which suggests that the shrimp have an intolerance to environments with a solids concentration above 800 mg L⁻¹. Our results show that intermediate levels of bioflocs (TSS between 400 and 600 mg L⁻¹) appear to be more suitable to superintensive culture of L. vannamei since they create factors propitious for maintaining the system’s productivity and stability     

旱田改水田对黑土pH及微生物类群的影响

[目的]探明旱田改水田后黑土酸碱度及土壤微生物的变化。[方法]通过5点采样法取样,利用平板菌落计数法对相关微生物类群数量进行研究。[结果]旱田改为水田后,土壤pH显著上升;细菌和真菌数量明显增多,放线菌数量变化不明显,纤维素分解菌数量逐渐下降,在5~10 cm土层,其数量较旱田显著降低(P0.05),有机磷细菌和无机磷细菌数量略有增加;在0~5 cm土层水田的B/F比旱田显著降低,但其他土层间B/F差异不大。[结论]短期旱田改水田能初步缓解土壤的酸化问题;旱田改水田后土壤微生物数量发生了变化;水田中各土层间B/F较一致,说明土壤微生物类群结构更为稳定。     

紫外辐射增加对40个割手密无性系土壤微生物种群数量动态和多样性的影响

采用大田试验方法,研究了模拟紫外辐射(UV—B,280—310nm)增加对40个割手密无性系土壤微生物种群数量的影响。结果表明．(1)UV—B处理条件下,土壤细菌数量、真菌数量和放线菌数量主要表现为下降,而且分别在成熟初期、分蘖期和伸长期降幅最大。36号和38号细菌数量、真菌数量和放线菌数量在3个时期下降显着。(2)UV—B处理．也会导致一些无性系在不同的时期细菌数量、真菌数量或放线菌数量上升,但没有一致的变化,其中以9号、19号上升较明显。(3)UV—B处理,土壤微生物多样性指数增高,以分蘖期变化最大。细菌的变化对多样性指数的影响较大。部分无性系的多样性指数下降,24号降低明显。UV—B辐射增加可导致割手密土壤微生物数量的降低,土壤微生物多样性增加。     

沙颍河周口市段水质的生物学监测及评价

对沙颍河周口段水质进行检测,包括微生物学检测、叶绿素a测定等,结合理化检测对其水质做出初步评价。结果表明大闸上游段水质为β中污带,贫营养型;胜利桥段水质为α-中污带,中营养型;地区医院段水质为多污带,属富营养型。     

菌渣还田对菜地土壤理化性状、微生物及酶活性的影响研究

为了研究菌渣还田对土壤质量改善的效果和机制,为菌渣还田在农业生产上推广利用提供依据。本研究采用双孢蘑菇采收后菌渣直接还田,设计还田量为0（对照）、TMR（1/3还田）、SMR（1/2还田）和AMR（全部还田）4个处理,菌渣还田并种植2季茄子后测定土壤理化性状、微生物及酶活性的变化。结果表明：菌渣还田对土壤各个指标影响都较为明显,（1）菌渣还田改善土壤容重,提高土壤pH,减轻土壤连作障碍;（2）与对照相比,菌渣还田显著提高土壤有机质、氮、磷、钾含量,但是对土壤铵态氮含量则有显著降低作用;（3）菌渣还田能够增加土壤微生物群落的规模及土壤酶活性,有利于土壤质量的改善,同时还增强了土壤潜在的抑病能力。     

菌渣还田对菜地土壤理化性状、微生物及酶活性的影响研究

为了研究菌渣还田对土壤质量改善的效果和机制,为菌渣还田在农业生产上推广利用提供依据。本研究采用双孢蘑菇采收后菌渣直接还田,设计还田量为0(对照)、TMR(三分之一还田)、SMR(二分之一)还田和AMR(全部还田)4个处理,菌渣还田并种植两季茄子后测定土壤理化性状、微生物及酶活性的变化。结果表明：菌渣还田对土壤各个指标影响都较为明显。1)菌渣还田改善土壤容重、提高土壤pH,减轻土壤连作障碍;2)与对照相比,菌渣还田显著提高土壤有机质、氮、磷、钾含量,但是对土壤铵态氮含量则有显著降低作用3)菌渣还田能够增加土壤微生物群落的规模及土壤酶活性,从根本上有利于土壤质量的改善,同时还增强了土壤潜在的抑病能力。