广西不同林龄桉树人工林叶—凋落物—土壤C、N、P生态化学计量特征

C、N、P元素的养分循环过程是影响森林生态系统结构与功能的关键因素。以广西不同林龄桉树人工林为研究对象,分析桉树幼龄林(1a)、中龄林(2a)、近熟林(3a)、成熟林(5a)、过熟林(8a)叶—凋落物—土壤的C、N、P化学计量特征及其内在联系,探讨林龄对桉树人工林生态化学计量的影响,为桉树人工林可持续经营提供参考。结果表明:1)桉树人工林叶、土壤呈现高C低N、P的元素格局,凋落物呈现高C、P低N的元素格局;叶的C、N、P含量从幼龄林到近熟林呈先增后减趋势,反映桉树人工林早期对养分需求旺盛,随年龄增大需求减小。2)不同林龄叶C、N、P差异显著(P<0.05),凋落物与土壤的N、P、C∶N、C∶P、N∶P均差异显著(P<0.05),凋落物C∶P与叶N∶P、C∶P显著正相关(P<0.05),凋落物N∶P与叶的C∶P、N∶P之间呈极显著正相关(P<0.01),说明凋落物养分源自叶,土壤与叶的C、N、P均不相关。3)与叶相比,凋落物中N、P含量偏低,C∶N、C∶P偏高;土壤C∶P、N∶P偏低,说明土壤P素分解较快,可适时施以磷肥来弥补土壤速效磷的不足;土壤C∶N偏高表明土壤有机质具有较慢的矿化作用。中龄林、近熟林和成熟林叶N∶P<14,生长过程受N限制;中龄林、近熟林和成熟林凋落物分解的主要限制性元素是N,而幼龄林凋落物分解的主要限制性元素是P。     

内蒙古大兴安岭林区蝶类种的记述(二)粉蝶科

文章记述了内蒙古大兴安岭林区鳞翅目粉蝶科已知19种,包括斑缘豆粉蝶Colias erate Esper、北黎豆粉蝶Colias viluiensis Men、黑缘豆粉蝶Colias palaeno Linnaeus、黎明豆粉蝶Colias aurora Esp、北方豆粉蝶Colias melinos Ev、兴安豆粉蝶Colias tychede Boeber、橙黄豆粉蝶Colias fieldii Menetries、镏金豆粉蝶Colias chrysoheme Esper、绢粉蝶Aporia crataegiL、菜粉蝶Pieris rapaeL、东方菜粉蝶Pieris canidia Sparrman、暗脉粉蝶Pieris napiL、黑纹粉蝶Pieris melete Menetries、云粉蝶Pontia daplidiceL、绿云粉蝶Pontia chloridice Hubner、钩粉蝶Gonepteryx rhamniL、尖钩粉蝶Gonepteryx aspsiaMen、莫氏小粉蝶Leptidea morsei Fenton和突角小粉蝶Leptidea amurensis Mentries。并对其形态特征、习性、寄主和分布进行了简要介绍。     

云南6种阔叶材的识别与利用研究

1989年就西双版纳普文林区采集到的槭果黄杞、思茅栲、多穗石栎、柴桂、披针叶楠、勐海山胡椒6个材种的木材标本，对滇产这些树种木材的宏观构造、微观构造、物理力学性质和利用进行了研究。其结果供开发利用云南的阔叶材作依据。     

Biogeochemical impacts of clearfelling and reforestation on blanket-peatland streams: II. major ions and dissolved organic carbon

Streams and drains in blanket-peatland forest in western Ireland were sampled weekly over 5 years, 1996–2000, using continuous, depth-proportional passive sampling. Analysis was for pH, alkalinity by Gran titration, anions by IC, metals by ICP, aluminium speciation by loaded-resin exchange, and dissolved organic carbon (DOC) by absorbance at 320 nm.

Effects of felling are identified graphically from two forest drains whose catchments (both about 1 ha) were clearfelled, and partial clearfelling of one larger catchment (somewhat over 1 km²), in summer 1999. Calcium concentrations and alkalinity were increased in the drain- and streamwater from the felled areas. The pH was increased in drains, while in the larger stream, pH range decreased while the mean increased. Phosphorus increased markedly with clearfell, in the absence of recent fertilising, and also increased with fertilising; these results are reported in an accompanying paper. Ammonium-nitrogen concentrations were increased in the two drains with felling, and temporarily decreased in the larger stream. Nitrate increased in some cases. Potassium and manganese concentrations also increased. Concentrations of DOC and organic monomeric aluminium increased gradually, subject to a continuing strong annual cycle. There were no clearfelling effects on concentrations of solphate, suspended solids or inorganic monomeric aluminium. In the two drains (fully clearfelled), concentrations of sodium, chloride and magnesium, and conductivity, were all reduced after felling. Fertilising effects other than for phosphorus were indistinct.

Effects of the combined clearfell–reforestation treatment were testable statistically, using randomised intervention analysis, between two larger streams (1 km²) as a treatment–control comparison. There were statistically significant positive responses in streamwater concentrations of nitrate, potassium, calcium, DOC and aluminium fractions. The implications for management practice depend on whether the loss of nutrients is sustainable for future crop productivity, and whether critical limits and loads of receiving ecosystems are exceeded.     

叶蜂科两新种记述(膜翅目,叶蜂科)

本文记述了中国叶蜂科两新种，吴茱萸蛞蝓叶蜂及山药叶蜂。文中附有形态特征图２幅。     

福建南安五台山西南桦不同种源生长差异比较

引进西南桦25个种源在福建五台山进行栽培试验,生长及寒害调查初步显示25个种源中A、V、T、Y、K、QI、、P等8个种源表现出生长快、产量高、干形好的特点,适于当地栽培和发展;M、C、G、S、F、O、J等7个种源生长差,不宜在当地推广和发展;D、E、N、U、H、X、R、B、L、W等10个种源生长中等,可根据实际生产需要选择应用。     

瓜州绿洲植被退化原因及保护对策

瓜洲县近年来人口数量增长和土地开发规模过大,成为水资源紧张、植被退化、生态环境质量下降的重要原因之一,对绿洲农业生产和人居环境影响很大,因此,严格控制人口数量的增长和土地开发规模,大力发展节水农业,保障生态供水,加强对现有植被的保护,维护生态平衡,是瓜洲县实现可持续发展必须认真考虑的问题。     

日本竹工艺文化概观

日本竹工艺文化历史久,种类多,有10类562种,具有产生早、应用广和实用性、普遍性、工艺性的特点,经历了产生、兴盛、低迷的过程,现在呈现出复苏苗头。     

中国跳小蜂科六新记录属六新记录种(膜翅目:小蜂总科)

记述了采自吉林，辽宁，河北，山东，福建等省的6种跳小蜂，即巴库小雅跳小蜂Baeocharis pascuorum Mayr，茧蜂伊思跳小蜂Echthrodryinus azureus(Mercet)。黄色伊伦跳小蜂Erencytus dewitzi Mahdihassan,柯木玛赫跳小蜂Mahencyrtus comora Walker。栖桔副暗跳小蜂Parablatticida citri(Mercet)。玛娜利捷行跳小蜂Trechnites manaliensis Hayat,Alam et Agarwal，除玛娜利捷行跳小蜂出自梨木虱Psylla chinensis，茧蜂伊思跳小蜂寄主有误外，其余4种为扫网采集，这6种跳小蜂在我国属首次报道。主要寄生各种树木上的介壳虫和木虱。这6个属也是中国分布新记录属。     

抓住机遇,迎接挑战,促进西双版纳茶业发展

分析我国加入WTO后茶业的机遇和面临的严竣问题 ,提出西双版纳茶业发展应加速低产茶园改造 ,推广无性系良种 ;保护茶园生态 ,应用生物技术 ;调整产品结构 ,开拓国内外市场 ;建立龙头产业 ,实施名牌战备等四项建议。随着中国加入WTO步伐的加快 ,为我国茶叶出口创造了前所未有的机遇 ,中国是世界产茶大国 ,19世纪几乎垄断了整个世界茶叶市场 ,进入 2 0世纪 ,肯尼亚、斯里兰卡后来居上。 1999年全国茶叶产量达 6 8万t,出口仅2 0 .2 9万t,云南茶叶产量 7.5万t,出口仅 1.0 3万t,版纳茶叶产量 1.5万t,几乎全部内销。国茶出口不畅 ,其主要原因是受经营机制和产品质量的制约 ,如何抓住中国加入WTO的机遇 ,振兴国茶在国际市场的声誉 ,促进版纳茶业再上新台阶 ,必须认真分析存在的问题 ,改革现行茶叶经营机制 ,依靠科技进步 ,提高产品的产量和质量