冰冻灾害前后矿区废弃地栾树杜英混交林生态系统养分含量的比较

对冰冻灾害前后湖南湘潭锰矿矿区废弃地的栾树、杜英混交林生态系统的地表水、土壤、林木及死地被物的养分含量进行对比研究.结果表明:冰冻灾害后,林地地表水的pH值、电导率、溶解氧、K、Ca、Mg含量明显减少,Zn、Mn、Pb含量显著增加;林内土壤含水量、全P、全K含量显著增加,速效N、速效P、速效K含量明显减少,微量元素Cu、Pb、Co含量增加,Fe、Zn、Mn、Cd、Ni含量减少;林木枝、叶、干中含水量均显著减少,树干中N、P、Ca、Mg、Cu、Zn、Mn、Cd、Ni、Pb、Co含量增加,树枝和树叶中P、K、Mg减少,而Cu、Fe、Zn、Mn、Cd、Ni、Pb、Co含量却增加;林地上的死地被物中K、Mg在各组分(未分解、半分解、已分解)含量降低,Cu、Fe、Mn、Ni、Co含量增加.可为突发性自然干扰对植物生命活动的影响及抗御机理的研究提供基础数据.     

石漠化石灰土与水土保持植物葛藤化学元素含量特征

对贵州花溪区石灰土及水土保持植物葛藤化学元素的含量进行了研究.结果表明:(1)石灰土pH值为7.98,有机质含量为56.60 g·kg-1.全N、全P含量分别为3.56,0.64 g·kg-1,N和P有效率低,速效N仅占全N含量的0.47%.速效P仅占全P的1.46%.全K含量为6.92 g·kg-1.属缺K型土壤.全Ca、全Mg含量分别为15.44、2.74 g·kg-1.(2)微量元素含量依次排序为Fe>Mn>Zn>Ni>Pb>Cu>Co>Cd.全Pb、全Zn、全Cu含量均未超过我国土壤环境质量标准(GB15618-1995)中的3级标准,可以作为林地使用.(3)水土保持植物葛藤体内不同元素含量的差异较大,N、K、Ca元素含量在10 g·kg-1以上,P、Mg元素含量为l～6 g·kg-1,Fe元素在1 000 mg·kg-1以上,Zn、Mn、Pb、Cu元素含量为10～100 mg·kg-1,Cd、Ni元素含量<5 mg·kg-1.(4)葛藤对土壤中N、P、K、Ca、Mg元素的积累能力最强,其次是对Zn、Cd,Cu、Pb元素,而对Mn、Ni、Fe元素的积累能力最弱.研究结果可为石漠化石灰土的植被修复提供理论依据.     

桤木人工林细根与土壤养分含量季节动态变化

对桤木人工林细根、土壤养分含量的季节变化及其两者之间的关系进行了研究.结果表明:(1)桤木细根中大量元素N、Ca、K、Mg、P含量冬季高,春季最低;微量元素Fe、Mn、Zn、Cu、Pb、Ni、Cd含量冬季最低,春夏季较高.(2)土壤各层中大量元素N、Ca、K、Mg、P含量冬季最低,夏季最高;微量元素Mn、Zn含量在冬季最低,秋季最高;Fe、Ni、Pb、Cu、Cd含量在冬季最高,春秋较低.(3)细根和土壤中大量元素含量在冬季存在负相关关系,微量元素Fe、Ni、Cd含量在一年四季均存在显著负相关关系,Mn、Cu含量在春季、夏季和秋季存在负相关关系,Zn、Pb含量在春季、夏季和秋季存在正相关关系.     

桤木人工林根系—土壤复合系统养分含量的变化规律

对桤木人工林根系-土壤复合系统中大量元素、微量元素、土壤有机质含量和pH值等的季节动态变化进行了研究,结果表明:在桤木根系中大量元素N、Ca、K、Mg、P含量冬季最高,春季最低,微量元素Fe、Mn、Zn、Cu、Pb、Ni、Cd含量冬季最低,春夏季较高;土壤中大量元素N、Ca、K、Mg、P含量冬季最低、夏季最高,微量元素Mn、Zn含量在冬季最低、秋季最高,Fe、Ni、Pb、Cu、Cd含量在冬季最高、春秋较低;土壤有机质含量、pH值的季节动态变化与根系大量元素变化趋势保持一致;土壤各层有机质含量大小顺序为0～15 cm层、＞15～30 cm层、＞30 cm层,pH值大小顺序为＞15～30 cm层、0～15 cm层、＞30 cm层.     

油茶林果实成熟期养分分配特征

以常宁市10年生油茶作为试材,对油茶养分分配规律、油茶林土壤养分与树体各器官营养元素含量的相关性进行研究,旨在为油茶营养诊断以及配方施肥提供科学依据。结果表明:油茶各器官中,大量元素含量由高到低排序依次为N、Ca、K、Mg、P,微量元素含量由高到低排序依次为Mn、Fe、Pb、Zn、Cu、Cd;土壤大量元素含量由高到低排序依次为Ca、N、K、P、Mg,微量元素含量由高到低排序依次为Fe、Pb、Zn、Cu、Mn、Cd。土壤养分含量与油茶各器官养分指标具有不同程度的相关性,与油茶干的养分含量相关性最为紧密;土壤N、Zn、Mn、Pb、K含量与油茶植株养分元素含量的关系最为紧密;土壤Mn与油茶各器官Mn元素含量均呈现正相关;土壤N与油茶干中N含量呈现极显著相关;土壤Cd元素含量和油茶各器官中Cd元素含量多存在负相关性。     

薜荔及其生长的土壤营养元素含量特征

对城市垂直绿化和水土保持新材料——薜荔进行了研究,结果表明:(1)土壤pH值为4.61;有机质含量为33.23 g.kg-1;全N、全P含量分别为1.021、0.27 g.kg-1,且有效率低,分别为4.29%和3.15%;全K含量为4.26g.kg-1,属缺K型土壤;全Ca、全Mg含量分别为0.59、8.51 g.kg-1。(2)土壤微量元素含量依次排序为FeMnZnCuPbNiCoCd,全Pb、全Zn、全Cu含量均未超过我国土壤环境质量标准(GB15618-1995)中的3级标准,可以作为林地使用。(3)薜荔体内不同营养含量差异较大,N、K、Ca元素含量在10 g.kg-1以上,P、Mg、S元素含量在10g.kg-1以下;Fe、Mn元素含量在50 mg.kg-1以上,Cu、Zn、Pb、B元素含量为5~10 mg.kg-1,Cd、Ni、Co元素含量在10 mg.kg-1以下。(4)土壤有机碳含量为15.19~23.98 g.kg-1,薜荔体内有机碳含量为411.11~510.80 g.kg-1。研究结果可为薜荔的深入研究提供理论依据。     

贵州都匀马尾松种子园针叶DRIS营养诊断分析

通过对都匀1．5代无性系种子园20年生马尾松针叶中N、P、K、Ca、Mg、Cu、Zn、Fe、Mn、B等营养元素含量变化的测定和分析,初步筛选出N／P、K／N、Ca／N、Mg／N、N／Cu、zn／N、N／Fe、K／P、Ca／P、P／Mg、P／Cu、P／Zn、Fe／P、K／Ca、K／Mg、K／Cu、K／Zn、Fe／K、Ca／Mg、Ca／Cu、Ca／Zn、Fe／Ca、MgJCu、Zn／Mg、Fe／Mg、Zn／Cu、Fe／Cu、Fe／Zn共28对元素比值为重要参数,对贵州都匀马尾松种子园针叶作DRIS营养诊断分析。结果表明,该地区马尾松针叶内Mn含量过高,平均值为767．01mg／kg,而B含量较低,仅为12．95mg／kg,马尾松的需肥顺序为Cu〉P〉Zn〉Mg〉Ca〉N〉K〉Fe。     

模拟酸雨对3种盆栽灌木幼苗叶矿质元素含量的影响

采用盆栽方法，以3种不同pH值（3．0、4．0、5．0）的模拟酸雨溶液对红檵木、杜鹃、夏鹃幼苗进行浇灌处理，研究不同pH值的酸雨对幼苗叶矿质元素含量的影响．结果表明：模拟酸雨对3种灌木幼苗叶矿质元素含量均有一定影响，3种幼苗叶中的大多数矿质元素含量变化不一致，表明不同植物的不同元素对酸雨的反应不同；各酸雨处理红檵木幼苗叶K、Mg、Mn、Ni、S、Al的含量较对照增加，其中Al、Ni含量是随着酸雨pH值的降低而逐渐增加．Zn含量比对照含量有所减少，N、P、Ca、Fe、Cu、Cd、Pb含量不随酸雨pH值的变化而变化．红檵木幼苗叶Al含量与模拟酸雨的pH值达到显著负相关；3种酸雨处理后的杜鹃幼苗叶P、Cu、Mn、Pb含量均比对照增加．其中P、Cu含量是随酸度的增大而逐渐增加，Ca、Zn含量比对照有所减少，N、K、Mg、S、Al、Fe、Ni、CA含量没有随着酸度变化而随之变化的趋势，P含量与模拟酸雨的pH值达到显著负相关；3种酸雨处理后的夏鹃幼苗叶P、K、Mg、Al、Fe、Cu、Mn、Ni、Pb含量比对照增加．其中P、Ni是随酸度增加逐渐增加，Zn含量比对照减少，N、Ca、S、Cd含量则表现为有的酸雨处理增加，有的下降，Ni含量与模拟酸雨的pH值达到显著负相关．该项研究可为南方绿化植物的选择提供理论依据．     

洞庭湖西岸区防护林土壤与植物微量元素含量特征

对洞庭湖西岸区4种防护林地土壤与植物中微量元素含量进行研究。结果表明:(1)环湖低丘平原封山育林和补植封山育林的水土保持林、平原湖区防护林土壤pH值为4.54~5.27,呈酸性反应;防浪护堤林土壤pH值为8.18,呈碱性反应。(2)全Cu、全Fe、全Zn以环湖低丘平原补植封山育林水土保持林土壤含量最高;全Mn、全Cd、全Ni、全Pb却以防浪护堤林土壤含量最高;全Co则以环湖低丘平原封山育林水土保持林土壤含量最高。(3)4种防护林土壤微量元素含量均表现为FeMnZnNiCuPbCoCd,Pb、Zn、Cu和Cd含量均未超过国家规定的三级标准;各防护林群落中植物体内不同微量元素含量差异很大,同一元素在不同植物体内含量的变化范围亦很大。(4)植物对土壤中Cd的吸收能力最强,对Mn、Zn、Cu、Ni、Pb其次,对Fe最弱;木本植物青冈、冬青和山矾具有较强的Cd积累能力。研究结果可为土壤环境质量评价及防护林体系建设提供理论依据。     

红锥人工幼林营养特性研究

对不同月份红锥叶片中营养元素含量的变化及其结构进行研究,结果表明,叶片中N、P、K、Ca、Mg、Mn、Fe、Cu、Zn营养元素含量呈季节性变化,普遍地在生长初期（春季）较高,生长旺期（夏季）最低,而秋冬季生长缓慢时由于积累所致而略有回升;叶片中常量元素含量以N、K、P较高,依次排序为：N〉K〉P〉Mg〉Ca,微量元素含量以Mn、Fe为高,依次排序为：Mn〉Fe〉Zn〉Cu,N、P、K、Ca、Mg、Mn、Fe、Zn、Cu比例为：7.40∶1.00∶5.96∶0.30∶0.51∶1.10∶0.16∶0.05∶0.01;根据研究结果及南方山地的土壤特点,红锥人工幼林的施肥时间宜在春季或春夏之交季节,在肥种及配比上,应在施用大量元素N、P、K、Mg、Ca的基础上配施微肥Zn,配比为N∶P∶K∶Ca∶Mg∶Zn=7.40∶1.00∶5.96∶0.30∶0.51∶0.05.     

Carbon and nitrogen storage in agroforests, tree plantations, and pastures in western Oregon, USA

Pastures store over 90% of their carbon and nitrogen below-ground as soil organic matter. In contrast, temperate conifer forests often store large amounts of organic matter above-ground in woody plant tissue and fibrous litter. Silvopastures, which combine managed pastures with forest trees, should accrete more carbon and nitrogen than pastures or timber plantations because they may produce more total annual biomass and have both forest and grassland nutrient cycling patterns active. This hypothesis was investigated by conducting carbon and nitrogen inventories on three replications of 11 year-old Douglas-fir (Pseudotsuga menziesii)/perennial ryegrass (Lolium perenne)/subclover (Trifolium subterraneum) agroforests, ryegrasss/subclover pastures, and Douglas-fir timber plantations near Corvallis, Oregon in August 2000. Over the 11 years since planting, agroforests accumulated approximately 740 kg ha^–1 year ^–1 more C than forests and 520 kg ha^–1 year^–1 more C than pastures. Agroforests stored approximately 12% of C and 2% of N aboveground compared to 9% of C and 1% of N above ground in plantations and less than 1% of N and C aboveground in pastures. Total N content of agroforests and pastures, both of which included a nitrogen-fixing legume, were approximately 530 and 1200 kg ha^–1 greater than plantations, respectively. These results support the proposition that agroforests, such as silvopastures, may be more efficient at accreting C than plantations or pasture monocultures. However, pastures may accrete more N than agroforests or plantations. This apparent separation of response in obviously interrelated agroecosystem processes, points out the difficulty in using forest plantation or pasture research results to predict outcomes for mixed systems such as agroforests. This revised version was published online in June 2006 with corrections to the Cover Date.     

Stammfaulen in Douglasien-, Kiefern-, Fichten-Mischbestanden1

Butt rot in mixed conifer stands. 70 years old Pseudotsuga menziesii trees on sandy soil, grown together with Pinus syhestris, Picea abies, Fagus sylvatica were analysed for butt rot. 73 % resp. 70 % of the Douglas fir, 13% resp. 28% of the Scotch pine and 82% resp. 84% of the Norway spruce showed decay. The most frequent fungi in Pseudotsuga were Heterobasidion annosum, Calocera viscosa, Sparassis crispa, in Pinus Sparassis crispa and in Picea Heterobasidion annosum. In a neighbouring stand with 85 years old Pseudotsuga menziesii - more often thinned than the 70 years old stand - only 23 % of the trees were with decay.     

Agroforestry in central,northern, and eastern Europe

Integrated management of natural resources and the multiple use of trees and forests have prevailed in most European societies since prehistoric times. In the Middle Ages, expanding and intensified agriculture resulted in the separation of trees from agricultural fields. During the last century, with the introduction of sustainable and highly productive forest management, the goal of increased wood production has been achieved in most parts of central, northern, and eastern Europe. Today, agroforestry is not considered to be an important land-use option within the region; however, there are many practices that could rightfully be classified as agroforestry. These include tree/crop systems in which trees provide products and/or environmental benefits, and tree/animal systems in which animals are grazed in forests or open woodlands.The future seems to offer some prospects for agroforestry. Large areas, hitherto used for food production, are either marginally suited to agriculture, or will probably be taken out of production due to agricultural policy considerations. Agroforestry may, at least in part, offer alternatives for the use of such lands. The availability of (surplus) fertile soils, capital, and labor may provide incentives for site-adapted forms of agroforestry, including improved fallow management. The focus of such systems would be on maintenance of biodiversity in the landscape, environmental protection, recreation, and product diversification.There are numerous expectations as to what agroforestry might provide for the land holder and for society as a whole. These expectations should be carefully analyzed and evaluated prior to political decisions on future land use. The promotion of agroforestry requires overall investment; agroforestry does not happen by itself. A set of integrated actions — not isolated efforts — must be implemented if agroforestry is to become a successful land-use option.     

Plant diversity, population structure, and regeneration status in disturbed tropical forests in Assam, northeast India

We investigated the plant population structure and the phy-tosociological and regeneration status in two disturbed tropical forests in Assam Province, the Hojai Reserve Forest and Kumorakata Reserve Fo...     

乌盟后山干旱半干旱地区沙漠化治理模式探讨

地处阴山以北的乌盟后山地区,土地的风蚀沙化十分严重,北部五旗县80%的耕地遭风蚀危害,10%的草场荒漠化.草场退化,粮食产量下降,农牧业生产长期低而不稳.同时风蚀沙化也危害交通、水利设施和村镇安全.自乌盟实施"进退还"战略以来,在恢复植被、改善生态环境方面上成效显著,但在治理方式上以单一的灌草模式为主,缺乏生物多样性,并由于草种寿命短造成重复建设,为此,本文提出一些治理模式供讨论.     

Malay ethno-medico botany in Machang,Kelantan, Malaysia

A survey of the Malay ethno-medico botany in the Machang district, Kelantan state, Malaysia, identified 146 species used by the villagers to treat various ailments.     

Fine root dynamics, coarse root biomass, root distribution, and soil respiration in a multispecies riparian buffer in Central Iowa, USA

By influencing belowground processes, streamside vegetation affects soil processes important to surface water quality. We conducted this study to compare root distributions and dynamics, and total soil respiration among six sites comprising an agricultural buffer system: poplar (Populus × euroamericana‘ Eugenei), switchgrass, cool-season pasture grasses, corn (Zea mays L.), and soybean (Glycine max (L.) Merr.). The dynamics of fine (0--2 mm) and small roots (2--5 mm) were assessed by sequentially collecting 35 cm deep, 5.4 cm diameter cores from April through November. Coarse roots were described by excavating 1 × 1 × 2 m pits and collecting all roots in 20 cm depth increments. Root distributions within the soil profile were determined by counting roots that intersected the walls of the excavated pits. Soil respiration was measured monthly from July to October using the soda-lime technique. Over the sampling period, live fine-root biomass in the top 35 cm of soil averaged over 6 Mg ha^-1 for the cool-season grass, poplar, and switchgrass sites while root biomass in the crop fields was < 2.3 Mg ha^-1 at its maximum. Roots of trees, cool-season grasses, and switchgrass extended to more than 1.5 m in depth, with switchgrass roots being more widely distributed in deeper horizons. Root density was significantly greater under switchgrass and cool-season grasses than under corn or soybean. Soil respiration rates, which ranged from 1.4--7.2 g C m^-2 day^-1, were up to twice as high under the poplar, switchgrass and cool-season grasses as in the cropped fields. Abundant fine roots, deep rooting depths, and high soil respiration rates in the multispecies riparian buffer zones suggest that these buffer systems added more organic matter to the soil profile, and therefore provided better conditions for nutrient sequestration within the riparian buffers. This revised version was published online in June 2006 with corrections to the Cover Date.     

Integration of pines,pastures, and cattle in south Georgia,USA

Agroforestry Systems - Native forages of southern United States are frequently low in nutrients and poorly digestible, while improved pastures are the opposite. Since this area produces rapid...     

Carbon, nitrogen, organic phosphorus, microbial biomass and N mineralization in soils under cacao agroforestry systems in Bahia, Brazil

Large amounts of plant litter deposited in cacao agroforestry systems play a key role in nutrient cycling. Organic matter, nitrogen and phosphorus cycling and microbial biomass were investigated in cacao agroforestry systems on Latosols and Cambisols in Bahia, Brazil. The objective of this study was to characterize the microbial C and N, mineralizable N and organic P in two soil orders under three types of cacao agroforestry systems and an adjacent natural forest in Bahia, Brazil and also to evaluate the relationship between P fractions, microbial biomass and mineralized N with other soil attributes. Overall, the average stocks of organic C, total N and total organic P across all systems for 0?C50?cm soil depth were 89,072, 8,838 and 790?kg?ha^?1, respectively. At this soil depth the average stock of labile organic P was 55.5?kg?ha^?1. For 0?C10?cm soil depth, there were large amounts of microbial biomass C (mean of 286?kg?ha^?1), microbial biomass N (mean of 168?kg?ha^?1) and mineralizable N (mean of 79?kg?ha^?1). Organic P (total and labile) was negatively related to organic C, reflecting that the dynamics of organic P in these cacao agroforestry systems are not directly associated with organic C dynamics in soils, in contrast to the dynamics of N. Furthermore, the amounts of soil microbial biomass, mineralizable N, and organic P could be relevant for cacao nutrition, considering the low amount of N and P exported in cacao seeds.     

Variation in Seed and Seedling Traits of Celtis australis, a Multipurpose Tree, in Central Himalaya, India

Seeds of Celtis australis were collected from 13 different sources, ranging from 550 to 1980 masl, in Central Himalaya, India. Significant (p = 0.05) variations were observed for seed traits among provenances. However, among various characters, seed weight exhibited maximum variation between seed populations compared to other morphological characters. Between provenances, seed weight ranged from 47.8 to 83.1 g/1000 seed, with mean value of 66.9 ± 10.7 g/1000 seed. Significant (p = 0.01) positive correlation was found between morphological characters of seeds including seed weight and elevational range of seed source. For one year old seedlings, average shoot and root growth was 61.1 ± 13.3 and 30.5 ± 5.4 cm, respectively, irrespective of provenance variation. Inter-comparing biomass yield of the seedlings with altitude, average biomass production was 8.4 ± 2.5, 9.4 ± 3.3 and 12.7 ± 1.7 g/plant, respectively, for low (550–1000 masl), middle (1050–1250 masl) and high (1350–1980 masl) altitudinal populations. Significant (p = 0.01) positive correlation between growth performance of seedlings and altitude of the seed source was recorded. Across the provenances, shoots had the highest proportion of total biomass (42.3%), followed by leaves (32.6%) and roots (24.6%). Among various provenances, Badiyargaon, Agroda, Guptakashi, Jakholi, Gajeli, Srinagar and Palampur populations produced heavier seedlings and grew faster compared to seedlings of other sources.