基于ComGIS的农用地分等单元及属性数据获取方法研究

以湖北省荆州市荆州区农用地分等评价为例，提出了在基于组件式地理信息系统(ComGIS)的农用地评价中，以矢量化并经校正后的土地利用现状图、土壤图、地貌图进行叠加产生的土地资源类型图作为农用地评价单元图，并通过与样点综合评价因素图层进行叠置分析来获取评价单元属性数据的新思路。在实际工作中取得了良好的效果，减少了工作量，提高了分等结果的科学性。     

农村住宅采暖技术试验研究

本文叙述了以太阳能采暖房为主体,利用连炕节柴灶余热作热源、吊炕为散热器的农村住宅采暖技术,它比仅靠太阳能采暖,室温提高3.49℃,12℃的采暖保证率达到90.33％。文中同时给出了该种采暖型式的热工参数设计模型和建筑结构模型。可供其它多种太阳能一常规能源综合采暖参考。     

Compartmentalization of mercury in biotic components of terrestrial flood plain ecosystems adjacent to the South River AT Waynesboro,VA

Water, Air, & Soil Pollution - Aquatic Hg contamination extending more than 200 km along the South River, South Fork of the Shenandoah River, and Shenandoah River in western VA has been...     

钙对盐胁迫下水稻幼苗抗氧化酶活性和膜脂过氧化作用的影响

研究了外源Ca2 对盐胁迫下耐盐性不同的两个水稻品种(武育粳3号和IR36)几种抗氧化酶活性及膜脂过氧化的影响。结果表明:适量的Ca2 供应能有效提高水稻叶片超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)以及抗坏血酸过氧化物酶(APX)的活性,使之维持在较高的水平上,并降低了丙二醛(MDA)含量和细胞膜透性。此外,外源Ca2 还增加了抗坏血酸(AsA)的含量,增强了水稻幼苗的根系活力。这表明适量的外源Ca2 供应提高水稻耐盐性的原因之一,在于其增强了植株的活性氧清除能力以及对细胞膜的稳定作用。     

The use of genetic resources in crop improvement: Lessons from China

The use of crop genetic resources in improvement programmes should be the ultimate objective of all undertakings in the field of germplasm resources. The present situation and future direction of the use of crop germplasm in China was assessed from responses to a questionnaire distributed to 165 plant breeders and curators nationwide. The general opinions for the limiting factors of germplasm utilization were also evaluated. Responses from the questionnaire indicated that the use of germplasm in breeding programmes is much more important than the direct use of germplasm in crop production as cultivars released. Among different types of crop genetic resources, released varieties and breeding lines contribute more to crop breeding. Wild relatives and genetic stocks, however, are expected to play a greater role in the future. Landraces will remain important in improvement. Limited useful germplasm available to breeders is the basic reason for the insufficient use of germplasm in crop breeding at present. The complex reasons which affect the availability of useful germplasm involve the research level, links between breeder and curator and others. To counter these, we propose some suggestions and measures which can be implemented in the near future.     

地下灌排兼用系统中田间土基透水管的机理分析及其现场成型机研制

通过对现有地下灌溉系统的分析，论述了田间地下土基透水管灌溉、排水兼用的可行性及机理分析。在对国内外暗管施工机进行分类归纳的基础上，研制出土基透水管现场成型机，可现场一次完成土基管的成型、固壁、防渗、镶嵌渗水条等工序，初步对样机进行了田间试验，验证其结构合理性、经济性、并对土壤的破坏成型机理进行了分析     

Soil organic and inorganic carbon sequestration by consecutive biochar application: Results from a decade field experiment

Biochar addition can expand soil organic carbon (SOC) stock and has potential ability in mitigating climate change. Also, some incubation experiments have shown that biochar can increase soil inorganic carbon (SIC) contents. However, there is no direct evidence for this from the field experiment. In order to make up the sparseness of available data resulting from the long‐term effect of biochar amendment on soil carbon fractions, here we detected the contents and stocks of the bulk SIC and SOC fractions based on a 10‐year field experiment of consecutive biochar application in Shandong Province, China. There are three biochar treatments as no‐biochar (control), and biochar application at 4.5 Mg ha^?1 year^?1 (B4.5) and 9.0 Mg ha^?1 year^?1 (B9.0), respectively. The results showed that biochar application significantly enhanced SIC content (3.2%–24.3%), >53 μm particulate organic carbon content (POC, 38.2%–166.2%) and total soil organic carbon content (15.8%–82.2%), compared with the no‐biochar control. However, <53 μm silt–clay‐associated organic carbon (SCOC) content was significantly decreased (14%–27%) under the B9.0 treatment. Our study provides the direct field evidence that SIC contributed to carbon sequestration after the biochar application, and indicates that the applied biochar was allocated mainly in POC fraction. Further, the decreased SCOC and increased microbial biomass carbon contents observed in field suggest that the biochar application might exert a positive priming effect on native soil organic carbon.     

浙江省低丘缓坡区水土流失及其对策

浙江省低丘缓坡区有土地资源3万8235km^2,对浙江省经济建设与社会发展具有重要意义。阐述浙江省低丘缓坡区土地资源开发利用的主要领域及发展趋势,分析低丘缓坡土地资源开发利用中水土保持存在的主要问题,提出水土流失综合治理的对策。     

农业机械污染排放控制技术的现状与展望

农业机械作为一种重要的非道路机械类型,其主要动力源为柴油机,而柴油机固有的燃烧方式会导致其颗粒物(PM)和氮氧化物(NOx)等污染物排放严重,开展农业机械污染排放控制技术的研究对人体健康和环境保护均具有重要意义。该文从农业机械排放法规、降低农业机械污染排放的单项技术路线、满足更高排放限值要求的组合技术路线3个方面进行阐述。农业机械排放法规分析了欧盟、美国和中国法规对排放限值和测试循环的要求以及各国法规的差异。中国目前正在实施的农业机械国III排放标准,与欧盟的Stage IV和美国Tier IV标准相比,排放限值相对宽松;欧盟农业机械排放法规的NRSC测试循环主要包括8工况循环和5工况循环,而中国和美国规定,19 k W以下的非恒定转速的农业机械柴油机也可使用6工况循环进行测试;欧盟和中国规定污染物测量的最终结果为冷启动循环结果的10%和热启动循环结果的90%的加权,而美国将冷启动循环结果的比例调低至5%。单项技术路线对油品技术、机内净化技术和机外排气后处理技术进行了介绍。其中,油品技术包括提升燃油和润滑油品质、采用替代燃料等;机内净化技术包括农业机械柴油机本体优化设计、增压及增压中冷、燃油喷射优化和废气再循环(exhaust gas recirculation,EGR)等;机外排气后处理技术包括柴油机氧化催化转化技术(diesel oxidation catalyst,DOC)、柴油机颗粒捕集技术(diesel particulate filter,DPF)和选择性催化还原技术(selective catalytic reduction,SCR)等。组合技术路线总结了满足国III和国IV阶段以及国外最新排放标准的技术路线。"优化燃烧+SCR"技术路线的柴油机比采用"EGR+DPF/CDPF"技术路线的柴油机节省5%~7%的油耗,若扣除尿素消耗,前者仍有一定节油优势;模块构建和单体式后处理系统等先进的农业机械污染排放控制技术是满足Stage IV/Tier IV和Stage V的重要技术路线。最后,针对农业机械污染排放控制技术研究,进行了总结和展望。为满足未来国IV排放标准,加装机外排气后处理催化器已经成为一种重要手段;开发低成本、高净化效率的集成式机外排气后处理催化器,是未来农业机械污染排放控制的重要研究方向。     

渠道衬砌抗渗型粉煤灰-稻壳混凝土抗渗性能试验

为了满足渠道衬砌的需要,提高稻壳混凝土的抗渗性能,在稻壳混凝土中加入了粉煤灰。该文通过试验对渠道衬砌抗渗型粉煤灰-稻壳混凝土的抗渗性能进行了研究,得到粉煤灰质量分数、稻壳质量分数和水灰比对粉煤灰稻壳混凝土抗渗性能的影响规律,同时得到了粉煤灰-稻壳混凝土相对渗透系数小于0.783×10-8 cm/s的混凝土配合比。通过对混凝土抗渗性能主效应分析得到混凝土抗渗性能的影响因素顺序：水灰比>稻壳质量分数>粉煤灰质量分数;粉煤灰-稻壳混凝土的相对渗透系数随着粉煤灰质量分数和稻壳质量分数的增大呈现出先减小后增大的抛物线的变化趋势,随着水灰比的增大呈现出一直增大的线性变化的规律。试验结果表明在不降低混凝土导热系数的前提下,在稻壳混凝土中掺入粉煤灰后确实能提高稻壳混凝土的抗渗性能。