Trace Organic Matter in the Ria Formosa,Portugal

The Ria Formosa lagoon, Portugal, receives organic matter from many natural and anthropogenic sources. This paper presents an overview of the contribution these sources made through the use of lipid biomarkers. Sixty-one surface sediment samples were collected and analysed for a range of lipids. Sewage materials were confined to regions within 2 km of discharge points; phytoplankton biomarkers (sterols and fatty acids) suggest production was greatest in the inner parts of the lagoon that also have greatest inorganic nutrient enrichment; terrestrial organic matter was present in relatively low concentrations as shown by both sterol and fatty alcohols; bacteria were widespread although the Sulphate Reducing Bacteria (SRBs, shown by the presence of 3-OH fatty acids) were located near but not adjacent to sewage discharge points.     

石灰性土壤中高效解磷细菌菌株的分离、筛选及组合

对石灰性土壤样品进行了解磷细菌的分离和筛选,得到具有明显溶磷圈的解磷细菌71株.分析了菌株分泌磷酸酶、释放速效磷及pH降低等综合因素和特征,研究了菌株生长动态.最后筛选出解磷能力较强且无拮抗反应的6株解磷细菌,并将其组合成为解磷细菌菌群.图8表2参17     

燃煤烟气脱硫副产物在酸性土上的农用价值与利用原理

燃煤烟气脱硫副产物作为废弃物对环境的潜在威胁,促使人们对其资源化利用研究的重视。文章针对红壤地区土壤普遍缺乏营养元素的问题,通过分析盆栽和田间试验结果,探讨燃煤烟气脱硫副产物在酸性土壤上的农用价值与利用原理。结果表明,燃煤烟气脱硫副产物富含作物所需的营养元素,而红壤地区土壤又普遍缺乏这些元素;它具有独特的形态特征和理化性能,在酸性土壤中可以产生协同效应,因而具极高的农用价值。在酸性土壤上适量施用,可以提高土壤养分含量,改善土壤理化性质,提高土壤供肥性能和持水能力,促进作物对养分的吸收,从而达到废弃物农业资源化利用的目的。     

内蒙古典型草原土壤不同剖面深度CO_2通量格局及其驱动因子

土壤CO2的释放能够显著增加大气牛CO2的浓度,增强温室效应,从而对全球气候和环境变化产生重要影响.但是,不同的土壤层对CO2通量的贡献量有很大的差异.文章通过挖坑法结合红外气体分析法研究了内蒙古草原典犁针茅(Stipa krylovii)群落和羊草(Leymus chinensis)群落不同剖面深度土壤CO2通量格局以及影响CO2通量的驱动因素.结果表明,表层土壤移走后,土壤CO2通量的变化可分为瞬时、短期、长期三种格局.新剖面上最初的0～21 min内释放的CO2通量最均大于初始土壤表层CO2通量,而且两者比值随土壤深度增加而增大,也随土壤CO2生产能力增强而增大.2～4 d后,新剖面CO2通量持续下降至低于初始土壤表层CO2通量的水平.形成短期稳定状态.更长时间后,新剖面则逐渐表现出与初始土壤剖面表层相近的CO2通量特征.我们认为,(1)在新剖面形成时的CO2通量瞬时和短期格局主要受土壤中存留的原始CO2的浓度及其扩散过程控制,(2)长期格局则由资源水平和环境条件共同决定的土壤CO2生产能力主导.文章进一步揭示了建立包含垂直分层的SOC分解和CO2扩散过程的生态系统模型的必要性.     

无瓣海桑和互花米草群落土壤化感作用比较

为揭示不同植物群落土壤在无瓣海桑(Sonneratia apetala)控制互花米草(Spartina alterniflora)中的作用,利用化感生物测定的方法,选用黑麦草(Lolium perenne)为受体,对比分析红树林无瓣海桑群落、互花米草群落以及无瓣海桑+互花米草群落土壤水提液的化感作用大小。结果表明3,种植物群落土壤水提液对黑麦草具有化感作用,无瓣海桑群落土壤和无瓣海桑+互花米草群落土壤水提液对黑麦草根长和苗高的影响表现出低促高抑的现象;ρ为0.25 g·mL-1的土壤水提液对黑麦草种子发芽和幼苗生长影响不大,1.0 g·mL-1土壤水提液对黑麦草根长和苗高产生显著影响,加入活性碳之后能减弱水提液的化感作用。ρ为0.25或0.5 g·mL-1条件下3,种土壤浸提液对黑麦草发芽率的影响无显著差异;ρ为1.0 g·mL-1的3种水提液都显著抑制黑麦草根长,而无瓣海桑群落土壤水提液表现出更强的化感作用,ρ为1.0 g·mL-1的土壤水提液显著抑制黑麦草苗高,无瓣海桑群落土壤对苗高的抑制作用显著强于互花米草群落土壤(P<0.01)。以黑麦草为受体,无瓣海桑群落土壤化感作用强于互花米草群落土壤,通过根系分...     

Abiotic control on the dissipation of chlorpyrifos spiked in an Udic Ferrisol at a lower dosage

The dissipation routes of chlorpyrifos spiked in an Udic Ferrisol at the dosage of 400 ng g^?1, which represents a residual level after an agricultural application, were studied in a laboratory, using the natural soil under three moisture regimes, sterilised, and organic matter-free soils in the dark at 20°C. The obtained results showed that higher soil moisture caused faster dissipation, and the abiotic and biotic contributions to the total dissipated amount of the applied chlorpyrifos in the soil accounted for 77.3–85.2% and 14.7–22.7%, respectively. In the sterilised soil, the contribution of organic matter to chlorpyrifos dissipation was noticed to account for 95% in the earlier two weeks, and was nearly equal to that of soil minerals two weeks after the incubation.     

土壤钙的生物有效性及与其它元素的相互作用

根据国内有关土壤钙素的研究文献、总结了土壤钙的生物有效性.土壤钙与其它元素的相互作用,以及钙在土壤中的固定、移动的研究进展,提出了钙肥的施用原则.其施用原则应该是平衡且适量。     

长期定位施肥对土壤生理转化菌群的影响

针对哈尔滨黑土28 a长期定位施肥现状进行土壤生理转化菌群测试分析,采用稀释平板法和MPN法测定不同施肥处理土壤的微生物各生理群的数量.结果表明:施肥处理的土壤微生物多样性指数最高,微生物种类多,群落结构较复杂,同不施肥处理之间的土壤微生物群落结构组成存在显著差异.     

Effects of salinity on soil bacterial and archaeal community in estuarine wetlands and its implications for carbon sequestration: verification in the Yellow River Delta

Soils from two typical tidal salt marshes with varied salinity in the Yellow River Delta wetland were analysed to determine possible effects of salinity on soil carbon sequestration through changes in soil microbiology. The mean soil respiration (SR) of the salt water–fresh water mixing zone (MZ) was 2.89 times higher than that of the coastal zone (CZ) (4.73 and 1.63?μmol?m^?2?s^?1, respectively, p?Pseudomonas sp. and Limnobacter sp. that might have led to its higher dehydrogenase activity and respiratory rates. Additionally, the CZ possessed more Halobacteria and Thaumarchaeota with the ability to fix CO₂ than the MZ. Significantly lower soil salinity in MZ (4.25?g?kg^?1) was suitable for β-Proteobacteria, but detrimental for Halobacteria compared with CZ (7.09?g?kg^?1, p?相似文献   

土壤-纳滤系统处理再生水补充地下水的研究

为充分保障再生水回灌地下时的水质安全、提供高质量地下水资源,在土壤处理系统中嵌入纳滤技术强化对再生水的处理效果,并初步探讨土壤系统作为前处理对纳滤膜污染的控制机理.结果表明,未采用臭氧氧化预处理前,土壤处理对再生水DOC和UV254的平均去除率分别为22%和20%.臭氧氧化对UV254的平均去除率为51%,并将土壤对D...