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安阳市近10年来建成的水土保持工程的主要建设管理方式可分为3种,即:乡村组织治理,完成后分配给农户分散经营;乡村组织治理,由村成立专业队代表村集体管理;把小流域或荒山承包给个体或私人经济组织,由其自行治理和经营管护。3种建管方式中以后者为最优,其经济效益是分散经营管理的5倍、专业队经营管理的3.5倍。针对水保工程建设管理中存在的问题和适应农村税费改革等要求,提出了加快安阳市水保生态建设的建议。 相似文献
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我国滑坡、崩塌的区域特征、成因分析及其防御 总被引:2,自引:0,他引:2
论述了我国滑坡、崩塌的区域分布特征,滑坡和崩塌的危害程度,滑坡和崩塌类型和成因分析,并且提出了灾害的防御措施,以期达到环境保护成为社会发展过程中的一个重要组成部分。 相似文献
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为探讨硒、钴在提高苜蓿生长影响,在河南省沿黄滩区,开展了硒、钴单施和配施下对紫花苜蓿生长以及产量和品质影响研究。结果表明,硒、钴单施和配合基施均能够显著提高苜蓿从现蕾到开花期的净光合能力,降低呼吸消耗,提高单位叶面积干物质的生产速率,有利于苜蓿花前青干草生产和果实发育;其中,以硒570 g/hm2、钴762g/hm2配施下效果显著,青干草增产8.06%,种子千粒重可提高12.85%。单施钴和硒钴配施还能促进0—20 cm耕层苜蓿根瘤菌的生长和积累,增强苜蓿的固氮能力。说明硒钴合理基施对苜蓿青干草和优质种子生产具有很好的应用效果。 相似文献
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Much evidence has indicated that the occurrence of montmorillonite and vermiculite containing Al-interlayers is very common in solis, particularly acid soils. Viewed in the light of soil clay minerology, it would be required to investigate the properties of their original minerals. For the latter purpose, the Al-interlayer has been removed prior to the Mg-glycerol,K-saturation and heating tests for identification of montmorillonite and vermiculite. Its removal has been accomplished in sevsral ways; KOH plus KCl (1), NH4F, KCl plus HCl (2), Na-citrate (3),400C de hydroxylation-NaOH (4) dissolution. Although these methods are effective for the removal of Al-interlayers, they seem drastically to affect the minerals or are time-consuming. Inthe course of the study of hydroxy-Al interlaid complexes of expanding 2:1 layer lattice clay minerals, the authors have noticed the difference between the (001) spacings of hydroxy-Al complexes of montmorillonite and vermiculite; the former exhibited the 20 A basal spacing at room temperature against the 14 A spacing of the latter. This difference might be useful for differentiating montnmorillonite-chlorite intergrades in soils. 相似文献
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平原地区河道堤防滩地的水土流失,直接淤积河床,影响行洪安全。堤防滩地的水土流失是自然因素和人为因素共同作用的结果,以新修堤防的水土流失最为严重,对其防治须实行工程措施、植物措施和人为预防相结合。 相似文献
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The effects of biochar (maize biochar – MBC, wood biochar – WBC) and unfermented or fermented hydrochar (HTC) on the euedaphic Collembola Protaphorura fimata and on spring wheat were investigated in greenhouse experiments. The impact of char type, amount of fermented HTC, and MBC-Collembola interactions were assessed. Generally, shoot and root biomass as well as abundance of P. fimata were not affected by the different chars. However, with increasing amounts of fermented HTC the abundance of P. fimata declined, whereas shoot biomass of wheat increased. Moreover, MBC altered root morphology and resulted in thicker roots with higher volume. The latter was not apparent when Collembola were present. 相似文献
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Potatoes (Solarium tuberosum L.) and carrots (Daucus carota L.) were grown in the field on Tasmanian ferrosols (humic eutrudox) which had been limed either 2, 3, or 5 years earlier, and where tuber cadmium (Cd) concentrations in potatoes grown a few months after the liming had shown no lime response. In the current crops lime decreased potato tuber Cd by about 30% and carrot root Cd by about 50%. We attributed the decrease to more even and deeper mixing of the lime with the soil by the harvest of the first potatoes. Phosphorus (P) fertilizer residues from the earlier potato crops did not significantly affect tuber or root Cd, but there was a positive effect at 1 site where some high Cd P fertilizer had earlier been used. Neither lime nor P fertilizer residues affected potato or carrot yields. Analysis at one site of potato tubers from the upper part of the soil ridges showed that they had slightly higher Cd concentrations than did deeper tubers near the fertilizer band, whether P fertilizer was in the band or not. This suggests that either the Cd in the fertilizer band was relatively unimportant as a Cd source for the current crop, or that Cd was redistributed within the plant during the season, or both. Liming may be a suitable medium to long‐term strategy for decreasing Cd uptake by root crops, but site to site and seasonal variation can still be great, and knowledge of other major influences is needed for assurance of produce quality. Our observations need to be extended to sites which gives rise to higher Cd concentrations in agricultural produce, and to other soil types. Potato common scab was severe in the limed plots at one site. However, this site had grown 3 potato crops in 5 years, which probably exacerbated the disease. Potato processors in Tasmania demand a minimum of 5 years between successive crops which should slow any build up of scab due to liming, but more work on possible interactions between lime and rotation length on scab incidence is needed before liming can be recommended as a Cd control measure for potatoes. 相似文献
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水土流失动态监测与评价研究现状与问题 总被引:16,自引:3,他引:13
美国等国家已将遥感、GIS技术广泛应用于水土流失动态监测与预报,并开发出基于物理过程的土壤侵蚀预报模型。中国在水土流失地面观测、遥感监测方面已取得许多成果,但在区域土壤侵蚀评价、预报模型开发方面,缺少系列化观测与统计数据,已有的坡面土壤侵蚀模型等在通用性、适用性方面还存在不少问题。当前急需解决的问题是建立水土流失监测与评价指标体系,开发评价模型系统,建立国家水土保持信息系统 相似文献
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开发建设项目水土保持设施竣工验收程序和方法 总被引:2,自引:1,他引:2
开发建设项目水土保持设施的竣工验收 ,要严格遵循水利部《开发建设项目水土保持设施验收管理办法》 ,坚持验收合格的 4条标准 ,由具备资质的机构进行验收前的技术评估 ,验收程序和方法要符合国家验收规程的规定与要求 相似文献
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Glycinin-rich and beta-conglycinin-rich products are prepared by soy protein fractionation. Physicochemical characteristics of these proteins affect their unique, important functionality in food systems and industrial applications. Soybean isoflavones and saponins are phytochemicals with potential health benefits. Objectives of this protein fractionation research were to (1) improve protein and phytochemical extraction from defatted soy flakes and recovery in product fractions and (2) evaluate phytochemical partitioning and profile changes during fractionation. Extraction environments (pH, ethanol concentration, temperature, and water-to-flake ratio) were each varied during bench-scale optimization. Optimized conditions of 45 degrees C and 10:1 water-to-flake ratio were compared with previous conditions of 20 degrees C and 15:1 water-to-flake ratio and a soy protein isolate process at pilot scale. Optimized conditions yielded more beta-conglycinin with higher isoflavone and saponin concentrations, but fraction purity was diminished by glycinin contamination. Bench-scale data demonstrated that increased phytochemical extraction did not translate into increased concentrations in product fractions. 相似文献
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赣州市水土流失面积1964-1988年呈增长趋势,1988年以后呈减少趋势,章、贡两江输沙量1988年以后逐渐减少,尤其是1998年以来显著减少。事实证明,人为破坏、重治轻防是水土流失加剧的根本原因,预防为主、综合防治是我市水土保持的成功之路。40年来水土流失与章、贡两江水沙变化态势是赣州市水土保持工作的客观反映。 相似文献
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吉林省水土流失十分严重 ,多年来 ,在各级政府和领导的高度重视下 ,目前累计治理水土流失面积 483 0 8km2 ,水土保持工作取得显著成效。进入 2 1世纪 ,吉林省水土保持面临许多困难和问题 ,必须依法强化监督、全面开展黑土区水土流失综合防治、依靠生态自然修复能力恢复林草植被 ,加大科技开发与成果转化 ,实现建设生态省的战略目标 相似文献
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Separation and analysis of diastereomers and enantiomers of cypermethrin and cyfluthrin by gas chromatography 总被引:5,自引:0,他引:5
Synthetic pyrethroid (SP) insecticides are of environmental significance because of their high aquatic toxicity. Due to their chirality, SP compounds contain multiple diastereomers and enantiomers. However, due to great structural similarities and lack of isomer standards, gas chromatographic (GC) analysis of SP diastereomers or enantiomers is poorly developed. In this study, we used a HP-5 column to separate the diastereomers and a beta-cyclodextrin-based enantioselective column (BGB-172) to separate the enantiomers of cypermethrin (CP) and cyfluthrin (CF). Resolved peaks were identified by comparing chromatograms of isomer-enriched CP products. Diastereomers of both CP and CF were separated on the HP-5 column. On the BGB-172 column, enantiomers of all cis diastereomers were separated, while those of trans diastereomers were not separated. The elution order appears to be regulated by configuration, a finding which may allow peak identification in the absence of isomer standards. When coupled with electron capture detection, the developed methods had low detection limits and may be used for analysis of SP diastereomers and enantiomers in environmental samples. 相似文献
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Experiments were conducted to study the influences of synthetic bayerite, non-crystalline aluminum oxide (N-AlOH), goethite, non-crystalline iron oxide (N-FeOH) and kaolinite on the adsorption, activity, kinetics and thermal stability of invertase. Adsorption of invertase on iron, aluminum oxides fitted Langmuir equation. The amount of invertase held on the minerals followed the sequence kaolinite > goethite > N-AlOH > bayerite > N-FeOH. No correlation was found between enzyme adsorption and the specific surface area of minerals examined. The differences in the surface structure of minerals and the arrangement of enzymatic molecules on mineral surfaces led to the different capacities of minerals for enzyme adsorption. The adsorption of invertase on bayerite, N-AlOH, goethite, N-FeOH and kaolinite was differently affected by pH. The order for the activity of invertase adsorbed on minerals was N-FeOH > N-AlOH > bayerite > reak goethite > kaolinite. The inhibition effect of minerals on enzyme activity was kaolinite > crystalline oxides > non-crystalline oxides. The pH optimum of iron oxide- and aluminum oxide-invertase complexes was similar to that of free enzyme (pH 4.0), whereas the pH optimum of kaolinite-invertase complex was one pH unit higher than that of free enzyme. The affinity to substrate and the maximum reaction velocity as well as the thermal stability of combined invertase were lower than those of the free enzyme. 相似文献