秦岭林区雷击火的发生和预防   总被引：1，自引：0，他引：1  

王会福  龚立群 《陕西林业科技》2013,(5):69-70,72

结合实践,分析了秦岭林区雷击火发生、蔓延的条件和趋势,提出了预防和扑救的技术与方法.  相似文献   

资源生态学视野下的毕节试验区畜牧业发展评析     

孙波  罗艳  王千里 《河南农业科学》2012,41(7):149-154

评析了毕节试验区畜牧业1988-2010年的发展成就、态势、优势、障碍和潜力,提出了毕节试验区畜牧业的发展定位、目标、重点和方向。  相似文献   

Soil organic matter fractionation as a tool for predicting nitrogen mineralization in silty arable soils     

M. A. Kader  S. Sleutel  S. A. Begum  K. D’Haene  K. Jegajeevagan  S. De Neve 《Soil Use and Management》2010,26(4):494-507

After decades of searching for a practical method to estimate the N mineralization capacity of soil, there is still no consistent methodology. Indeed it is important to have practical methods to estimate soil nitrogen release for plant uptake and that should be appropriate, less time consuming, and cost effective for farmers. We fractionated soil organic matter (SOM) to assess different fractions of SOM as predictors for net N mineralization measured from repacked (disturbed) and intact (undisturbed) soil cores in 14 weeks of laboratory incubations. A soil set consisting of surface soil from 18 cereal and root‐cropped arable fields was physically fractionated into coarse and fine free particulate OM (coarse fPOM and fine fPOM), intra‐microaggregate particulate OM (iPOM) and silt and clay sized OM. The silt and clay sized OM was further chemically fractionated by oxidation with 6% NaOCl to isolate an oxidation‐resistant OM fraction, followed by extraction of mineral bound OM with 10% HF (HF‐res OM). Stepwise multiple linear regression yielded a significant relationship between the annual N mineralization (kg N/ha) from undisturbed soil and coarse fPOM N (kg N/ha), silt and clay N (kg N/ha) and its C:N ratio (R² = 0.80; P < 0.01). The relative annual N mineralization (% of soil N) from disturbed soils was related to coarse fPOM N, HF‐res OC (% of soil organic carbon) and its C:N ratio (R² = 0.83; P < 0.01). Physical fractions of SOM were thus found to be the most useful predictors for estimating the annual N mineralization rate of undisturbed soils. However, the bioavailability of physical fractions was changed due to the disturbance of soil. For disturbed soils, a presumed stable chemical SOM fraction was found to be a relevant predictor indicating that this fraction still contains bio‐available N. The latter prompted a revision in our reasoning behind selective oxidation and extraction as tools for characterizing soil organic N quality with respect to N availability. Nonetheless, the present study also underscores the potential of a combined physical and chemical fractionation procedure for isolating and quantifying N fractions which preferentially contribute to bulk soil N mineralization. The N content or C:N ratio of such fractions may be used to predict N mineralization in arable soils.  相似文献   

桂东南特色文化资源数据库建设探析     

胡可东 《农业图书情报学刊》2011,23(9):26-29

特色数据库的建设是高校图书馆数字资源建设的一个重要组成部分，它是数字图书馆开展个性化信息服务最主要的信息资源。以玉林师范学院“桂东南特色文化资源数据库”的建设为例，希望通过对我馆在建库选题、数据的收集、加工、整理、发布和桂东南特色文化资源数据库体系框架等方面的具体阐述．为相关院校建设特色数据库提供参考。  相似文献   

高寒草地西北针茅生长发育特征及与气象因子的关系   总被引：2，自引：0，他引：2  

赵恒和  郭连云  赵年武 《干旱区资源与环境》2011,(11):187-192

利用1999～2009年连续11年的定位观测数据,研究了高寒草地西北针茅的生长发育特征与气象因子的关系。结果表明,在3月中旬,如果气温升高,返青日会推迟,这主要因为高温促使土壤水分蒸发,而土壤干旱阻碍返青;返青后,如果≥0℃的积温不足或累计日照时数不足,针茅的抽穗期会推迟;开花期的当日平均气温在10～20℃,如果抽穗-...  相似文献   

高寒藏区巴青1号青稞开花习性的研究     

王建锋  周学丽  童世贤 《四川草原》2012,(1):24-27

研究表明:巴青1号青稞在青海高寒地区种植,大部分在抽穗之后开花,小花开放顺序通常由中部向上下两端开放,单个花序开花持续时间为5~8d,群体开花时间可达到10d。一日开花高峰在上午09~11时和下午13~15时。青稞开花的适宜温度为17.2℃~22.6℃,相对湿度55%~65%,结实率为85.7%。  相似文献   

民国时期中华职业教育社乡村建设活动述论     

崔军伟  孙念超 《农业考古》2012,(1):315-319

20世纪20年代末30年代初,中国历史上形成了一次大规模的"乡村建设运动"。作为"足以代表这个运动的整个方面之较早者"——中华职业教育社"鉴于农村的衰落,与一般农业学校造就的人材,不合实际的需要,并且不能担当挽救农村衰落的重任,主张改变方向,把职业教育的范围扩大,深入到农村里去",(1)积极投入到乡村建设运动中,在长江三角洲地区展开了一系列的乡村建设活动。  相似文献   

西部欠发达地区农村图书馆建设对策研究   总被引：1，自引：0，他引：1  

李强 《农业图书情报学刊》2010,22(3):42-44

面对建设社会主义新农村的重大历史任务，本文通过对西部欠发达地区农村图书馆建设现状及发展滞后的原因分析．提出了适合西部农村图书馆发展的对策和建议。  相似文献   

高速公路沙害防治技术研究-以丹东-拉萨高速公路新地-麻黄沟段为例   总被引：3，自引：0，他引：3  

王智远  徐占云  崔琳  仇本灵  王越峰 《干旱区资源与环境》2005,19(5):204-208

本文以新地—麻黄沟高速公路防沙体系效益为依据,探讨分析了高速公路沙害的特点以及防沙体系建设的基本要求。研究表明,高速公路沙害防治需要采取适当抬高路基,建立稳固的防沙体系并要适当加大防护带宽度的综合措施。该地区公路防沙体系的结构配置对干旱、半干旱沙漠地区高速公路沙害防治具有一定的借鉴作用。  相似文献   

Phylogenetic Analysis of Sugarcane Rusts Based on Sequences of ITS, 5.8 S rDNA and D1/D2 Regions of LSU rDNA     

Eric V VIRTUDAZO  Hitoshi NAKAMURA  Makoto KAKISHIMA 《Journal of General Plant Pathology》2001,67(1):28-36

Phylogenetic analysis of sugarcane rusts based on sequences of ITS and the 5.8 S rDNA revealed two highly divergent ITS groups among isolates of Puccinia sp. sensu Muta, 1987 and P. kuehnii specimens. Although there is sufficient divergence (exceeding normal intraspecific variation) between the ITS regions of the two groups to support separation into different species, unusually high homology of the ITS group I sequences with those of members of Cronartium and identical sequences of the D1/D2 regions of the LSU rDNA for all the isolates of “Puccinia sp.” and P. kuehnii that otherwise exhibited different ITS sequences, suggest that the two highly divergent sequences may have resulted from abnormal genetic events leading to non-orthologous, intraspeciflc polymorphisms. The other sugarcane rust, P. melanocephala and the grass rusts, P. miscanthi and P. rufipes, were separated from “Puccinia sp.” and P. kuehnii and from each other in D1/D2 region analyses, indicating that D1/D2 region sequences may more correctly reflect phylogenetic relationships in these rusts than do the ITS regions. Further studies to examine differences in patho-genicity or finer morphological features within P. kuehnii that may be correlated with the high divergence in ITS sequences and experiments to determine if these two sequence types represent intraspeciflc polymorphism are necessary. Received 11 October 2000/ Accepted in revised form 24 November 2000  相似文献