环境重金属污染监测研究的指示物:小型哺乳动物和土壤动物

小型哺乳动物和土壤动物是陆地生态系统食物链中重要环节，在生物指示研究中具有十分重要的作用。鼠类和是环境重金属污染研究中最常用的指示物，其肝脏和肾脏是重金属富集的重要指示器官。蚯蚓和线虫不仅用以监测环境中土壤重金属总量，而且与土壤因素相结合还可以监测重金属的生态有效性。     

森林里的动物功臣

翻耕土壤赛过耕牛森林土壤是构成森林生态系统的最基本要素之一,是典型的生物衍体。居留在土壤中的动物可分小型动物(包括原生动物、各种蠕虫、线虫、螨、原始的无翅昆虫和有翅昆虫)、中型动物(包括蚯蚓,软体动物中的蜗牛和蛞蝓、多足类及昆虫等)和穴居森林土壤中的小型哺乳动物,它们是森林土壤和地被     

浅谈我国城市森林建设中存在的问题及对策

论述了城市森林在生态环境建设中的作用及其地位，及目前我国在城市森林建设中存在的问题与解决这些问题的对策。     

城市森林的理念及在岳阳市的实践

简述了城市森林的理念及森林进城对城市生态建设的重要意义,提出了岳阳市区实施森林进城(森林环城)工程建设内容及关键要素。     

城市森林建设中存在的问题及对策浅析

随着经济的发展,我国城市森林建设步伐加快,营造城市森林,打造绿色生态城市,已成为城市发展的新潮流。通过对我国城市森林建设的现状及存在问题的分析,探讨城市森林建设的新思路。     

在加蓬的热带雨林中探奇

中非刚果河流域的热带森林仅次于亚马孙河流域的热带雨林,是世界第二大热带雨林,被誉为非洲的“绿肺”,200万平方公里的森林中,生长着1．1万种植物、400多种哺乳动物、1000多种鸟类和150种爬行类动物。加蓬原始热带雨林是刚果河流域热带森林的重要组成部分。那里终年常绿,四季花开果香,得天独厚的旅游资源吸引着日趋增多的观光游客。     

道孚棕色森林土火烧后主要酶系活性及理化性质的演变

土壤剖面对比研究显示棕色森林土火烧后大生了剧烈生态演变,黑土变薄,容重加大,毛管孔隙减少,盐基饱和度下降,酸度削弱,有机质损失,NH_3—N挥发殆尽,速效P、K增加等.表层土壤酶火后活性升高的有脲酶、蛋白酶、过氧化物酶、H_2O_2酶,这与土壤通透状况改善、酶度降低相联系;降低的有转化酶、淀粉酶、磷酸酶,对应着容重加大,有机质减少和有效P增加;而纤维素酶,多酚氧化酶对火不敏感,酶活性剖面分布格局火后仍未改变.作者研究认为,为迅速恢复土壤酶系及相应微生物区系间的平衡,人工更新时对火烧迹地生境利用同型森林腐殖质土进行接种是必要的.     

浅谈我国城市森林建设中存在的问题及解决对策

论述了城市森林在生态环境建设中的作用，提出了目前我国城市森林建设中存在的问题与解决这些问题的对策。     

湖北森林在长江抗洪中发挥的生态作用及森林生态环境亟待建设的问题

本文从森林的蓄水滞洪、固土防淤、减灾救灾等方面论述了湖北森林在长江抗洪中发挥的生态作用，提出了加速国土绿化，加强对现有森林资源的有力保护，彻底改善生态环境是湖北林业当前面临的主要任务。     

Lime,sewage sludge and mineral fertilization in a silvopastoral system developed in very acid soils

In recent years, in the European Union, sewage sludge production has been increased as a result of EU policy (European directive 91/271/EEC). Organic matter and nutrient sewage sludge contents, principally nitrogen, indicate it can be used as fertilizer. The objective of the experiment was to compare the effect of no fertilization, three doses of sewage sludge, with or without liming, and the fertilization usually used in the region applied over a period of 3 years on pasture production and tree growth in a silvopastoral system. The experiment was conducted in the northwest of Spain. The soil was very acid (soil pH = 4.5) and had very low nutrient levels, especially P, that is related to site index. It was sown with a grass mixture (25 kg ha⁻¹ of Lolium perenne L. 10 kg ha⁻¹ of Dactylis glomerata L. and 4 kg ha⁻¹ of Trifolium repens L.) in Autumn 1997 under a plantation of 5-year-old Pinus radiata D. Don at a density of 1,667 trees ha⁻¹. Liming and sewage sludge fertilization increased soil pH and reduced saturated aluminium percentage in the interchange complex (Al/IC) in the soil, coming up the effect before with liming. Medium and high sewage sludge doses increased pasture production in the two first years. In a silvopastoral system, positive tree growth response to different fertilization treatments depended on tree age, initial soil fertility, soil pH, the relationship of competition with pasture production and previous liming application.     

施肥与抚育间伐对马尾松天然次生林土壤肥力的影响

经对地位指数为12～14的低山丘陵红壤区马尾松天然林进行施肥与抚育、间伐试验，4a后进行土壤肥力测定，结果表明：①氮、磷、钾肥无论是单施，还是任意二种或全营养配合施用，土壤全效及速效养分含量都有不同程度的提高，肥力状况均有明显改善。其中以全氮和速效磷的增幅为最大，全磷和速效氮的增幅次之，而以全钾和速效钾的增幅为最小；②施肥对土壤pH值具有一定的调节作用，并能显著提高土壤有机碳和有机质含量，因而明显改善土壤肥力状况，提高土壤保水保肥能力；③抚育与间伐对土壤速效氮、速效磷、速效钾含量以及土壤含水率、有机碳、有机质含量都有明显提高。其效果为抚育大于间伐，而间伐则以密度为110～120株／667m^2时效果为最佳。     

Accumulation of heavy metals in stemwood of forest tree plantations fertilized with different sewage sludge doses

The levels of heavy metals that accumulated in stemwood of mature trees grown for 20 years in a plantation in an abandoned peat quarry in areas that were fertilized with different amounts of domestic sewage sludge(180,360,and720 Mg ha~(-1) on a dry basis) were compared with trees grown in a reference nonfertilized area.Included in the study was a hybrid poplar(Populus tremula x Populus tremuloides) developed for use as an energy crop,three local tree species and one introduced tree species.The concentrations of Cd,Cr,Cu,Ni,Pb and Zn in the stemwood of the trees grown in the fertilized and nonfertilized fields were determined,and found to be significantly lower than their respective concentrations in the soil.Cd and Cr were found only in several wood samples at concentrations close to the limits of detection or qualification; therefore,they were not analyzed further.A correlation analysis suggested that 75%of the correlations between the concentrations of heavy metals in the stemwood and the concentrations in the soil were negative.The ability of trees to accumulate the metals from soil in most cases decreased for Cu and Ni; however,the correlations were not as clear for Pb and Zn.The followingsequence for the levels of heavy metals found in the stemwood of the analysed trees was Zn [ Pb [ Ni [ Cu [(Cr,Cd).The results of this study showed that the levels of heavy metals in the studied wood would not exceed the permitted limits of heavy metal pollution in the air and ash when used for energy production.     

油茶幼林施肥试验

选用氮肥、磷肥和钾肥3种肥料,采用3因素4水平试验设计,同时,单位面积配施相同施肥量的有机肥,2013年、2014年连续2年对油茶幼林进行施肥试验,共设11个处理;2012年、2013年、2014年分别观测树高、地径和冠幅,分析不同施肥处理对油茶幼林营养生长的影响。结果表明,连续2年施肥后,磷肥和钾肥相同的处理,其2年的树高的增长量均随着氮肥施用量的增加而加大;氮肥和钾肥相同的处理,其2年的树高、地径和冠幅的增长量均随着磷肥施用量的增加而加大;氮肥、磷肥相同的处理,其2年的树高、地径和冠幅的增长量均随着钾肥施用量的增加而加大;氮肥对地径和冠幅的影响规律性不明显。施肥效果最好的处理是配方中钾肥施用量最大的处理。建立的氮肥、磷肥和钾肥效应模型得出的最佳施肥量为:氮肥15.7 kg/667 m2、磷11.6 kg/667 m2、钾13.2 kg/667 m2。     

撩壕施肥对毛竹林分结构的影响

历时10年对撩壕施肥的毛竹林生长特性和林分结构变化进行调查研究,结果表明:(1)不同径级毛竹均分布在林分密度3 750~10 305株/hm~2的中密度到高密度的范围之内,当林分密度为8 250株/hm~2的中密度时,林分平均胸径和新竹平均胸径达到生长高峰;当林分密度为10 305株/hm~2的高密度时,平均枝下高、秆全高和枝下高占全高的比例也达到最大值。(2)撩壕施肥竹林立竹株数为8 625株/hm~2,其中胸径12~17 cm的大径竹占该竹林总株数61.2%,比对照竹林增加4.02倍;胸径9~11 cm的中径竹占该竹林总株数33.2%,比对照竹林增加38.4%;胸径8 cm以下的小径竹占该竹林总株数5.6%,为对照竹林的87.4%。(3)撩壕施肥竹林Ⅰ~Ⅳ度竹为幼、壮、中龄竹,立竹株数和蓄积量占林分比例均在70%以上,处于绝对优势,繁殖功能旺盛;Ⅴ~Ⅶ度竹为次老龄竹和老龄竹,立竹株数和蓄积量占林分比例均在30%以下,繁殖能力有所下降,但因能增加立竹密度,有利于为新竹提供营养。     

Long-term effects of repeated urea fertilization in Douglas-fir stands on forest floor nitrogen pools and nitrogen mineralization

In six Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] stands in the Puget Sound Region in Western Washington/USA, forest floor C and N pools were quantified on control plots and on plots that had been fertilized repeatedly with urea 8–30 years ago (total amount of applied N 0.9–1.1 Mg ha⁻¹). Additionally, net N mineralization and nitrification rates were assessed in field and laboratory incubation experiments. Forest floor C/N ratios were decreased on the fertilized plots of all sites compared to the respective control plots. The decreases were particularly strong at sites with initial C/N ratios larger than 30. On sites with low productivity (site index at age 50: <33 m), N fertilization resulted in considerable increases in forest floor N pools. Net N mineralization and nitrification during 12-week field incubation was negligible for the unfertilized and fertilized plots of all except one site (Pack Forest), where the stand had been clear-cut 2 years ago. The increases in N mineralization rates during 12-week laboratory incubation induced by repeated N fertilization showed an inverse relationship to the time elapsed since the last fertilizer application, and were generally larger at sites with initial forest floor C/N ratios >30. For the investigated sites, fertilization effects on net N mineralization sustained for at least 11 years after the last fertilizer application. Nitrification correlated strongly with the forest floor pH; significant formation of NO₃⁻ was observed only for O layers with a pH (H₂O) higher than 4.5.     

Commercial forest fertilization causes long-term residual effects in ground vegetation of boreal forests

Due to an increasing demand of forestry products, nitrogen (N) fertilization of coniferous forests may in the future become a standard silvicultural practice in parts of the boreal region that is not too remotely situated. Beside positive effects on productivity, forest fertilization may induce changes in species composition of the ground vegetation. More information on the magnitude of such side effects is needed to evaluate whether commercial forest fertilization is in accordance with principles of sustainable forestry and preservation of biodiversity.     

毛环竹造林施肥效应研究

采用正交试验设计方法 ,对毛环竹造林施肥、浇灌进行研究。结果表明 ,施肥对新鞭生长量、出笋数量、新竹高度和造林成活率有显著影响 ,施肥量以每穴施用尿素 5 0～ 10 0g、钙镁磷和硫酸钾各 5 0g为宜 ,增加施肥量的效果不明显 ,徒然增加成本 ,施氮肥过量还会对母竹产生毒害作用 ,降低造林成活率 ,影响成林速度。种植时 ,每个种植穴至少应浇水 5～ 7 5kg ,如氮肥施用过量则应浇水 10kg以上 ,以缓解氮肥对母竹产生的毒害作用。     

泡桐幼龄林配方施肥的初步研究

在测定土壤平衡解析磷和土壤钾位缓冲容量的基础上,根据林木施肥立地养分效应模型法,结合泡桐林的目标产量,提出了中等立地条件下白花泡桐幼龄林的施肥量,并进行了田间肥效校验试验研究。肥效校验试验共设计6个处理,即Ⅰ(N1P1K1)、Ⅱ(N2P2K2)、Ⅲ(N3P3K3)、Ⅳ(N4P4K4)、Ⅴ(N5P5K5)、Ⅵ(CK),3次重复。研究结果表明:不同施肥处理对泡桐幼龄林的胸径和树高增长均有显著性影响,区组间无显著差异。LSD多重比较检验后得出,施肥第一年后,处理Ⅲ对白花泡桐幼龄林的胸径增长效果最显著,但对树高增长的影响没有达到显著水平。施肥第二年后,处理Ⅳ对胸径增长效果最显著。而从树高的增长来看,处理Ⅱ的增长效果最佳。综合考虑,泡桐幼林生长最佳的N、P、K施肥量及最佳配比为Ⅲ(N3P3K3)。