闽南山区连续年龄序列桉树人工林土壤养分动态

对闽南山区连续年龄序列(2 a、3 a、4 a、5 a、6 a)的尾巨桉(Eucalyptus urophyllaxE.grandis)人工林土壤有机碳及氮、磷、钾含量进行了分析,以评价土壤养分随林分年龄的变化动态.土壤有机碳、全氮、水解氮、全磷、速效磷均表现出随林分年龄增加而增加,到4 a生时达到最大,随后则呈下降趋势,6 a生时下降到最低值.速效钾含量则随林分年龄增加逐步下降,6 a生林分0～20 cm、20～40 cm和40～60 cm这3个土层速效钾含量分别比2 a生下降了53.2%、44.4%和55.2%;土壤全钾含量也表现出一定的下降趋势.所有年龄林分的土壤有机碳、全氮、水解氮、全磷、速效磷和速效钾含量均随土层深度增加而降低,而土壤伞钾则表现出相反的趋势.因此,在桉树人工林经营过程中,应定期增施钾肥,适时施用有机肥及氮、磷肥,以控制地力衰退.图4表2参24     

Trees and rural households’ adaptation to local environmental change in the central highlands of Ethiopia

This study assesses the role of trees in adaptation strategies of rural households to local environmental change in the central highlands of Ethiopia. Change in tree cover was assessed by producing Land Use and Land Cover (LULC) maps using satellite remote sensing images, and household survey was conducted to generate socioeconomic data. The results show that tree cover has increased over the last 30 years, mostly in the form of eucalyptus woodlots around homesteads. Eucalyptus reportedly helps households pass through livelihood shocks and provide protection against negative effects of climate change and variability. Despite some concerns on the part of local agricultural experts that planting eucalyptus may affect future food production, farmers are converting their croplands into eucalyptus woodlots. We conclude that land use planning and proper allocation of land resource is important to improve local livelihoods while also supporting adaptation of communities to local environmental change in general and climate change in particular.     

Kinetic and isotherm error optimization studies for adsorption of atrazine and imidacloprid on bark of Eucalyptus tereticornis L.

The aim of this study was to establish the bark of Eucalyptus tereticornis L. (EB) as a low cost bio-adsorbent for the removal of imidacloprid and atrazine from aqueous medium. The pseudo-first-order (PFO), pseudo-second-order (PSO), Elovich and intra-particle diffusion (IPD) models were used to describe the kinetic data and rate constants were evaluated. Adsorption data was analysed using ten 2-, 3- and 4-parameter models viz. Freundlich, Jovanovic, Langmuir, Temkin, Koble–Corrigan, Redlich–Peterson, Sips, Toth, Radke–Prausnitz, and Fritz-Schluender isotherms. Six error functions were used to compute the best fit single component isotherm parameters by nonlinear regression analysis. The results showed that the sorption of atrazine was better explained by PSO model, whereas the sorption of imidacloprid followed the PFO kinetic model. Isotherm model optimization analysis suggested that the Freundlich along with Koble–Corrigan, Toth and Fritz-Schluender were the best models to predict atrazine and imidacloprid adsorption onto EB. Error analysis suggested that minimization of chi-square (χ²) error function provided the best determination of optimum parameter sets for all the isotherms.     

桉树人工林生态系统养分循环和平衡研究Ⅱ. 桉树人工林生态系统的养分循环

根据大量的观测分析资料,论述了刚果W5桉树人工林生态系统养分的地球化学循环和生物小循环。研究结果表明,每公顷每年通过地表径流和地下渗漏从生态系统输出的养分质量以K最多,达21.25 kg/(hm2a);其次为N,达17.21 kg/(hm2a)。桉树人工林生态系统养分流通质量的净变化值f(K)、f(Ca)为负值,f(N)、f(P)、f(Mg)为正值;桉树人工林生态系统养分的生物小循环研究表明,在一个轮伐期内,每公顷桉树吸收养分的质量,依次为Ca 429.03 kg/hm2,其次为N 277.01 kg/hm2和K 208.12 kg/hm2。而在一个轮伐期中归还的养分质量,Ca只有99.78 kg/hm2,K为113.04 kg/hm2。在养分循环率方面,与热带半落叶季雨林比较,桉树人工林生态系统的养分循环率要小得多,说明桉树人工林土壤养分趋向于减少。     

造纸污泥应用于人工速生桉培肥地力的资源化策略研究

造纸污泥是一种富含氮磷和有机质养分的有机废物,其中的养分资源可循环应用在速生桉培肥地力工程上.客观剖析了生物质能产业发展背景下,中国南方地区人工速生桉存在的环境生态效应,提出轮伐期缩短和忽视对有机肥的补充是造成当前速生桉地力退化严重的主要原因.基于现状,提出将造纸污泥好氧发酵无害化处理后,生产桉树专用有机肥,可最大化循环利用造纸废物养分资源,推进"林-纸-泥"一体化循环发展模式;提出资源化策略配套的发展资金和政策支持建议.     

广西罗城马尾松、杉木、桉树人工林碳储量及其动态变化

对广西罗城仫佬族自治县杉木（Cunninghamia lanceolata）、马尾松（Pinus massoniana）桉树（Eucalyptus grandis x E.urophylla）人工林生态系统碳含量、碳储量进行了研究,结果表明：不同发育阶段马尾松、杉木、桉树人工林林下植被含碳率变化幅度为37.96%~49.03%,枯落物含碳率为41.8%～49.6%之间,马尾松幼龄林林下植被含碳率最高,2年生桉树林枯落物含碳率最小。0~60 cm土层含碳率变化幅度为0.45%～2.17%,0~20 cm土层含碳率表现为杉木〉马尾松〉桉树。马尾松、杉木、桉树人工林生态系统碳储量分别为135.61、144.30、87.54 t.hm-2,马尾松和桉树人工林生态系统碳储量均表现为随林龄的增加而增加,马尾松幼龄和近熟林碳储量分别高于杉木,杉木中龄林碳储量高于马尾松中龄林。马尾松、杉木、桉树人工林乔木碳储量分别占其总碳储量的43.03%、34.44%、22.92%。马尾松、杉木、桉树人工林下植被碳储量表现为桉树（2.54 t.hm-2）〉杉木（1.91 t.hm-2）〉马尾松（0.89 t.hm-2）。马尾松、杉木、桉树人工林枯落物碳储量分别占其总碳储量的1.64%、4.56%、1.95%。马尾松、杉木、桉树人工林土壤碳储量分别为74.13、86.48、62.95 t.hm-2,杉木人工林土壤碳储量最高,桉树最小,0~20 cm土层碳储量成为土壤的主体,马尾松0~20 cm土层碳储量占其土壤总碳储量的47.03%,杉木占51.67%,桉树为42.58%。乔木和土壤碳储量成为整个森林生态系统的主要的碳储存库。     

An analysis of the environmental pressure exerted by the eucalyptus-based kraft pulp industry in Thailand

The study reported here focuses on the environmental pressure exerted by large-scale eucalyptus-based kraft pulp industry in Thailand. The objective of this study was to identify the most important sources of greenhouse gases, acidifying and eutrophying compounds and tropospheric ozone precursors, human toxicity compounds and solid waste associated with the kraft pulp industry. To this end, we performed an environmental systems analysis of the kraft pulp industry system in which we distinguished between two subsystems: the eucalyptus forestry subsystem and the kraft pulp production subsystem. The results indicate that the environmental pressure is caused by the kraft pulp production subsystem rather than by the eucalyptus forestry one. The chemical recovery unit was found to be the most important source of carbon dioxide (CO₂) and sulfur dioxide (SO₂) and responsible for more than one-half of the emissions of greenhouse gases and acidifying compounds from eucalyptus-based kraft pulp production in Thailand. Biomass combustion in the energy gene ration unit is an important source of nitrogen oxide (NO _x ) and carbon monoxide (CO) which in turn are responsible for over 50% of the emissions of tropospheric ozone precursors. About 73% of the eutrophication is caused by biological aerobic wastewater treatment emitting phosphorus (P). With respect to the eucalyptus forestry, only fertilizer use in eucalyptus plantations is a relevant source of pollution through the emission of nitrous oxide (N₂O) and phosphate (PO ₄ ³⁻ ).     

不同母质砖红壤上的桉树营养差异研究

在雷州桉树人工林下，两种类型的砖红壤由于受不同母质和质地的影响，土壤养分和桉树叶片养分质量分数有较大差异。本文着重研究了有桉树缺素现象的浅海沉积物砖红壤上的枝树叶片营养特点和桉叶片中各营养元素间的相互关系，结果表明桉树是喜锰植物，其营养元素间的相互关系较复杂，且不同树种情况有差别。     

雷州半岛桉树人工林地的生物改良研究

研究雷州半岛桉树人工林地的生物改良途径。结果表明；桉树林下间种绿肥、牧草或菠萝，可以提高林地覆盖度，增加林地枯落物，提高土壤肥力，促进桉树的生长。筛选出比较适宜于桉树人工林下间种的植物品种，并对间种的经济效益作了初步分析。     

桉树人工林地土壤肥力灰色关联分析

根据桉树人工林地土壤营养元素含量及土壤酶活性变化,利用灰色关联分析方法评价了桉树人工林地的土壤肥力,列出了以土壤营养元素含量及土壤酶为指标的土壤肥力水平排列顺序.文章认为,以土壤酶活性作为桉树林地土壤肥力的评价指标时,还需对它们的适宜范围作进一步探讨.