屋顶花园节水技术探讨

本文在分析屋顶花园用水问题的基础上,提出了可行的屋顶花园节水养护技术,包括选择抗旱植物和进行节水型植物配置,加强种植土和排水层的储水能力,使用喷灌、滴灌和地下滴灌等节水的灌溉方式。     

鸟类羽被防水性能的形态学基础

提出用水-羽毛接触点密度(Dp)的指标来描述鸟类廓羽表面的防水性能。29种鸟类胸部廓羽的检测表明,除了极少数物种以外,陆禽的Dp较小,涉禽和潜水鸟类的Dp居中,而游禽的Dp较大。这表明鸟类通过羽毛微观结构的变化来使羽毛具有相应水平的防水性能。因此,Dp是一个连接羽毛结构和功能的指标,对鸟类的适应性进化的研究具有重要意义。图3表1参9。     

Concentration variations of several ions in stream after a wildfire

In May 2006, a high intensity wildfire occurred in Songling forest region in Daxing＇an Mountains, China. The concentration changes of eight ions （K^＋, Na^＋, Ca^2＋, Mg^2＋, Cl^-, Br^-, NO3^- and SO4^2-） were measured in burned and tmbumed streams after fire from May to Oct., 2006. Results show that the most ions flux were higher in burned stream than that in unburned stream during the sampling period, and the greatest concentrations of most ions transported from burned stream occurred in July. After fire, the most amplitude chemical ion was Ca^2＋, whose average concentration was 5.50 mg·L^-1 higher than that in unburned stream, and the total concentration of every chemical ion presents a trend Ca^2＋〉SO4^2- 〉Na^＋〉Mg^2＋〉NO3^- . The average concentrations of Ca^2＋, SO4^2- , Na^＋＇Mg^2＋,NO3^- showed an increase trend, but those of K^＋, Cl^- , Br had a decreased trend. SO4^2- had the largest loss among these anions, followed by NO3^-. Overall, the increase degree of cation was greater than that of anion after burning.     

6种野生灌木的抗旱性研究

对胡颓子(Elaeagnus bockii Diels)、三颗针(Berberis julianaeSchneid)、金丝梅(Hypericum patulum Thumb)、十大功劳(Mahonia fortunei(Bindl)Fedde)、刺梨(Rosa roxburghii Trau)和火棘(Pyracantha fortuneana(Maxim)Li.)等6种野生灌木采取盆栽控水方式进行了水分胁迫,测定了各树种抗旱性的主要生理指标,并采用隶属函数法对6个树种进行综合评定,结果表明:叶片相对水分亏缺、保水力、脯氨酸含量、可溶性糖含量、丙二醛含量、相对电导率、叶绿素含量等是影响树种抗旱性的主要生理指标;6个树种的抗旱性强弱为三颗针>胡颓子>火棘>十大功劳>刺梨>金丝梅。     

水分胁迫对早实核桃生长和结果的影响

水分胁迫对早实核桃生长和结果的影响谷瑞升，郗荣庭，刘万生（河北农业大学园艺系保定０７１００１）（辽宁经济林研究所大连１１６０３１）关键词早实核桃，水分胁迫，生长和结果核桃是重要的经济林树种，早实核桃品种具有很高的栽培价值。然而我国的核桃产区集中于干旱...     

鄱阳湖水位特征与湿地生态保护

从分析江湖关系入手，研究鄱阳湖的水位及湿地生态特征，并提出人工控湖等加强湿地生态保护的对策建议。     

Decomposition of needle/leaf litter from Scots pine, black cherry, common oak and European beech at a conurbation forest site

Litter decomposition was studied for 2 years in a mixed forest serving as a water protection area (Rhine-Neckar conurbation, SW Germany). Two experiments differing in initial dry weight equivalent in litterbags were set up: one to compare decomposition of European beech leaves (Fagus sylvatica) with common oak leaves (Quercus robur), and the other comparing decomposition of Scots pine needles (Pinus sylvestris) with black cherry leaves (Prunus serotina Ehrh.), respectively. Mass losses were greater for oak litter than for beech (75.0 versus 34.6%), and for cherry litter than for pine (94.6 versus 68.3%). In both experiments, a strong initial loss of soluble compounds occurred. The changes in litter N and P concentrations and the decrease in C-to-N ratio coincided with changes in residual mass. However, neither tannin and phenolic concentrations nor NMR could explain the pronounced variation in mass loss after 2 years. Differences in litter palatability and toughness, nutrient contents and other organic compounds may be responsible for the considerable differences in residual mass between litter types. The fast decay of black cherry leaves appears to play a major role in the present humus dynamics at the studied site. Since black cherry has a high N demand, which is mainly met by root uptake from the forest floor, this species is crucial for internal N cycling at this conurbation forest site. These effects together may significantly contribute to prevent nitrate leaching from the forest ecosystem which is subject to a continuous N deposition on an elevated level.     

红锥天然林土壤理化性质及水源涵养功能的研究

对福建华安红锥天然林土壤理化性质及林下凋落物持水能力的分析表明 :红锥天然林土壤各营养元素含量丰富 ,表土层养分状况优于深土层 ,但土壤偏酸 ,淋溶与富铝化作用强烈。红锥天然林的土壤容重、孔隙度、持水量及林下凋落物的水源涵养功能均比一般杉木人工林优越。     

Soft X-ray observation of water distribution in the stem ofCryptomeria japonica D. Don II: Types found in wet-area distribution patterns in transverse sections of the stem

Using soft X-ray photography, two-dimensional observations were made of the water distribution within the green stem ofCryptomeria japonica D. Don. Variations in the distribution pattern of the wet area in the horizontal plane of the lower stem were described. The distribution patterns showed extreme variation among individual trees, with broad wet-area distribution types appearing, namely, the regularly distributed wet area and the irregularly distributed wet area. We defined five basic types of wet-area distribution patterns on the basis of their regularity or irregularity. It was concluded that the between-tree variation in the wet-area distribution causes the between-tree variation in the mean moisture content of the heartwood. The distribution patterns of the wet area were similar for individual trees within each plus-tree clone.Part of this paper was presented at 46th annual meeting of the Japan Wood Research Society at Kumamoto, April 1996     

Sedimentation associated with forest road surfacing in a bottomland hardwood ecosystem

Access systems are a necessary element of resource production in bottomland hardwood sites. However, road building may have a detrimental effect on hydrologic function of the site. This report describes initial results of a study designed to examine the effect of different road surfacing treatments on water quality.

Four surfacing treatments installed on two test roads included native soil, native soil with vegetative stabilization, 6 cm of gravel, and 15 cm of gravel over geotextile. During the first flooding season periodic sampling measured floodwater suspended sediments and location of erosion and sediment deposition within the road prism. Initial results suggest that sediment movement was confined to the road right-of-way, with no statistically significant sedimentation effects detected beyond the clearing limits of the road. The study is continuing for another field season.