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471.
Nongma Zongo Juliane Dao Désiré Jean-Pascal Lompo Kathrin Stenchly Christoph Steiner Delphine Manka'abusi Michel Papaoba Sedogo Andreas Buerkert Rainer Georg Joergensen 《植物养料与土壤学杂志》2023,186(2):188-195
Background
Little is known about the effects of gypsum application to remediate saline–sodic soils in the tropics and the role of microbial indicators in soil reclamation.Aims
Our study aimed at (1) remediating a highly weathered, irrigated sodic Lixisol under prolonged urban crop production by clean water and gypsum application and (2) to determine the remediation effects on soil microbial indices.Methods
A three-factorial on-farm experiment with maize (Zea mays L.) was used to study effects on soil microbial biomass of (1) soil degradation at two levels of salinity, (2) irrigation with clean water and wastewater, and (3) the impact of added gypsum during a typical growing season.Results
At the high-degradation site, the 0.5 M K2SO4 extractable carbon (C) content was 40% higher than at the low-degradation site. In addition, microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN) were 20% lower than at the low-degradation site, while fungal ergosterol was even 40% lower, leading to a 33% lower ergosterol/MBC ratio. Wastewater irrigation increased MBN but decreased ergosterol content at the low-degradation site while having no effect at the high-degradation site. Gypsum amendment led to higher MBN at the low-degradation site but to lower MBN at the high-degradation site. Gypsum amendment always increased the ergosterol content whereby this increase was stronger at the low-degradation site, especially in combination with wastewater irrigation.Conclusions
From a microbial perspective, high soil degradation levels should be avoided by treatment of a saline–sodic wastewater prior to its use for irrigation rather than relying on future remediation strategies of affected field sites. 相似文献472.
Ryser-Degiorgis MP Bischof DF Marreros N Willisch C Signer C Filli F Brosi G Frey J Vilei EM 《Veterinary microbiology》2009,134(3-4):368-374
Mycoplasma conjunctivae is considered the major cause of infectious keratoconjunctivitis (IKC) in Alpine ibex (Capra i. ibex) and chamois (Rupicapra r. rupicapra). While it is known that domestic sheep can act as healthy carriers for M. conjunctivae, this question has not been addressed in wild ungulates so far. In this study, bacteriological investigations and field observations were performed to assess whether free-ranging Alpine ibex can be healthy carriers of M. conjunctivae. Among 136 ibex without clinical signs of IKC, M. conjunctivae was identified 26 times (19.1%) by TaqMan PCR. To assess the potential pathogenicity of M. conjunctivae strains isolated from asymptomatic eyes, strains from three healthy ibex and from 15 IKC-ibex and IKC-chamois were analysed genetically by DNA sequence analysis of the variable part of the lppS gene. No significant differences were observed between strains from asymptomatic and clinically affected animals, reflecting the assumption that healthy ibex may act as carriers for M. conjunctivae strains that may be pathogenic for other individuals. Our results further indicate that development of IKC is associated with M. conjunctivae load in the eyes. In addition, a questionnaire survey revealed that IKC is generally less common in ibex than chamois and that infection in wild ungulates is not necessarily linked to the presence of sheep. These data support the hypothesis that apparently healthy ibex may be important in the epizootiology of IKC and indicate that host predilection may play a role in IKC development. 相似文献