Isotopic evidence and quantification assessment of in situ RDX biodegradation in the deep unsaturated zone

Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) is an explosive compound whose extensive use has resulted in significant contamination of soils and groundwater worldwide. We studied its in situ biodegradation along the unsaturated zone beneath an explosives wastewater lagoon using compound-specific isotope analysis (CSIA) of RDX in the unsaturated zone, together with biodegradation slurry experiments under anaerobic conditions. We found the highest degradation potential of RDX and its nitroso derivatives in the upper part of the soil profile while in the lower parts, RDX-degradation potential was lower and the nitroso derivatives tended to persist. This was also observed in the field, as reflected by the isotopic composition of RDX along the profile. We also found a correlation between biodegradation potential and clay content: biodegradation was further enhanced in layers characterized by high-clay content or in those influenced by the high-clay layers. In addition, in the presence of high organic matter content, further enhancement of biodegradation was observed. We obtained different isotopic enrichment factors (?) for RDX biodegradation in different sections of the unsaturated profile and suggest that different degradation pathways exist simultaneously in situ, in variable proportions. Using the range of enrichment factors, we were able to assess the biodegradation extent of RDX at different sampling points along the profile, which ranged between 30 and 99.4%. The novel application of CSIA together with slurry experiments provides better insight into degradation processes that are otherwise difficult to detect and assess.     

荒溪灾害危险区制图技术的研究

荒溪灾害危险区制图（长期预报）是同荒溪分类一并进行治理山区、建设山区、防治荒溪灾害、实现山区可持续发展战略的一项基础性工作。本研究介绍了荒溪灾害危险区制图的具体方法，并已在整个北京山区推广实施，为我国荒溪灾害预报场地的基础危险性研究做了一项行之有效的工作。     

太行山前冲洪积扇地区土壤水分动态变化特征研究

土壤水分含量对土壤物理性质和植被生长状态有重要影响，但土壤水分在时间上具有一定的变异性。大规模开采地下水导致地下水位急剧下降，包气带不断增厚，使土壤水分的储存、运移和转化发生了变化，影响了土壤水的动态变化特征。本研究利用连续多年的土壤水分观测数据，分析了太行山前包气带土壤水分动态变化特征，结果表明：土壤含水量受丰水年枯水年影响存在年际差异，根据不同季节土壤水分的动态特点，可将其划分为三个时期，即土壤水分消耗期土壤水分累积期和土壤水分相对稳定期。在垂向上，土壤含水量从上层向下逐渐增大，土壤水分变异程度随土壤深度的增加而减弱。     

城市新区文化景观建设中的意识原则

分析构成文化景观的各项要素和新区文化景观建设中存在的问题,提出在建设新区文化景观时应遵循的原则与意识。     

毛细管区带电泳测定饲料添加剂中酪蛋白磷酸肽含量的方法研究

利用毛细管区带电泳(CZE)对饲料添加剂中酪蛋白磷酸肽(CPP)样品进行分离，结果显示，用四硼酸钠缓冲溶液(20mmmol/L,pH9.2)及50cm×70μmi.d.石英毛细管柱，在工作电压30kV、检测波长200nm、柱温25℃的条件下，CPP得到较好的分离；同时，采用外标法对饲料添加剂样品中CPP各组分的含量进行了测定。     

建立健全闽台农业合作机制,推进海峡西岸经济区建设

闽台农业在资金、技术、市场、人力资源、自然资源、区域空间等方面具有很强的互补性.建立健全闽台农业合作机制,加强闽台农业合作沟通协商、产业及产品产销对接、人力资源和技术交流,有效化解风险,形成闽台全面农业合作体系,有利于实现闽台农业合作双赢,为海峡西岸经济区建设打下坚实基础.     

农牧交错区不同牧草时期放牧奶牛采食量与食性的研究

用饱和烷烃法对不同牧草时期放牧奶牛的采食量进行了测定.结果表明:放牧奶牛在牧草幼嫩期、旺盛期、枯黄期3期的采食量结果分别为:绝对采食量(kg/d)为11.54±0.66、13.83±0.55、5.75±0.32,采食量在牧草旺盛期时达到最高.采食组成幼嫩期以苔草为主、旺盛期以隐子草为主、枯黄期以赖草为主,这与草场植物的生长和奶牛的喜好有关.     

子午岭林区常见野生蔬菜营养成分分析

对子午岭林区19种野生蔬菜鲜样的水分、粗纤维、Fe、可溶性糖、可溶性蛋白和VC含量等进行了测定。试验结果表明,玉竹根部膨大部分纤维素含量最高,水芹Fe含量最高,蒲公英叶片可溶性糖含量最高,短柄五加叶片可溶性蛋白含量最高,VC含量最高的是苜蓿。除水分和可溶性糖含量外,野生蔬菜中其他营养指标基本上高于常见栽培蔬菜。     

现代设施蔬菜农业园区发展模式探索

从我国设施蔬菜的发展现状出发,针对生产型农业园区的规划理念、市场定位、近远期规划方向、功能分区、分项规划、规划保障等方面均进行了研究,对于生产型农业园区近期应具备的各项功能区进行了进一步的阐述与研究,同时针对设施蔬菜现代农业园区的远期建设模式进行了阐述。     

Formalizing agro-ecological engineering for future-oriented land use studies

Agriculture faces an array of interrelated problems that call for development of new and revision of existing cropping systems towards the multiple needs of the 21st century. Agro-ecological engineering approaches aimed at design and exploration of alternative land use systems at various scales may support the identification of appropriate land use options. Engineering approaches are based on mathematical representations of well-founded agro-ecological principles while taking into account available resources and prevailing land-related objectives. The goal of this paper is to contribute to the development of a formalized approach to engineer cropping systems at the land unit level that can be used as building blocks for systematic explorations of land use options at farm or regional scale. The approach for engineering cropping systems at the land unit level consists of three steps: (i) goal-driven design of cropping systems, (ii) quantification of biophysical production targets and (iii) definition of the optimal mix of inputs required to realize production targets. This paper describes the approach and illustrates it with examples from the Sudano-Sahelian zone of Mali. Explicit attention is paid to the required numerical tools and their application to analyze consequences of uncertainty in the performance of engineered cropping systems. Using numerical tools, uncertainty is made explicit with the aim to better manage or reduce it. Identification of uncertainty at the designer's desk allows taking uncertainty into account before applying engineered land use systems in regional model studies or testing such systems in practice. Problems related to the application of numerical tools are discussed, including the future role of agro-ecological engineering as independent discipline within agricultural science.