大海乡干热河谷造林技术模式

针对会泽县大海乡干热河谷地区在选择造林树种方面存在的问题及多年造林都没有取得成效的实际,依据干热河谷地区的自然条件,结合大海乡的发展需求,通过实验总结提出了大海乡干热河谷地区造林树种选择及营林措施的相关技术建议:在干热河谷地区造林,恢复干热河谷的植被,改善干热河谷地区的生态环境及生存环境.     

干热河谷生态环境特点与植被恢复技术探讨

干热河谷是我国西南地区独有的生态脆弱地带.受当地气候条件约束以及地形地貌等综合影响,植被以及土地存在严重的退化以及失衡等情况.目前,干热合谷地区业已成为我国造林的主要难点.结合干热河谷地区生态环境特性等进行分析,并就植被恢复等有关技术展开讨论,以期对干热河谷地区植被恢复以及环境改善等有积极帮助.     

云南元谋干热河谷区营造水土保持林的技术措施及初步成效

云南元谋干热河谷区营造水土保持林的技术措施及初步成效陈玉德，吴陇，喻赞仁关键词云南元谋，干热河谷，水土保持，造林技术元谋坝区是云南典型的干热河谷区。由于气候异常干旱炎热，生态环境遭到严重破坏，造林极度困难。３０多年来不少单位和部门先后多次到该地区进行...     

西南地区山地干热河谷困难立地生态修复措施

指出了近年来,造林绿化工程如火如荼进行,造林工作重心已从宜林地和荒山造林转移到困难立地植被恢复上。干热河谷由于干旱土壤贫瘠等原因,造林成活率和保存率低,是生态恢复的关键区域。总结了近年来我国干热河谷生态修复所取得成效,提出了适宜树种选择、整地方式、保水剂应用技术及坡改梯工程等对干热河谷的生态治理具有有效性。     

金沙江干热河谷区退耕还林工程项目营造林技术推广应用——以元谋县为例

通过在元谋干热河谷特殊的地理环境区域内实施退耕还林工程项目,开展了耐旱性树种选择研究和引进树种驯化适应性种植,推广使用良种壮苗、封山育林造林技术措施、营林造林配套技术应用,提高了造林预整地质量。着力推出保水剂技术应用,探讨了采用不同的技术措施以提高造林成活率、保存率和成林率。总结了元谋干热河谷区实施退耕还林工程项目中的经验,为金沙江干热河谷区植被恢复重建提供参考。     

干热河谷区生态修复研究进展

干热河谷区环境脆弱，生态修复困难。在我国，干热河谷主要分布在金沙江、红河、澜沧江和怒江等流域。结合国内外相关研究，梳理我国干热河谷区的气候特征、土壤特征、植被情况及造林技术，分析干热河谷区生态修复的优缺点，提出对策和建议。结果表明，我国干热河谷区生态修复树种配置较单一，造林成活率较低，综合效益较差；需优化造林树种及配置，创新造林方法及种植设备，保护原生生态环境，建立长期生态环境监测及效益评价体系。     

干热河谷典型地区植被恢复研究综述

以我国干热河谷典型地区的植被恢复为主要内容,对树种选择,造林整地、节水保水技术、植被恢复模式等方面的研究成果进行分类概述,提出干热河谷地区植被恢复的建议,为该区域多目标可持续的植被恢复提供参考,促进生态系统的恢复和社会经济的发展。     

元江县干热河谷造林进展与展望

在总结干热河谷的概念及干热河谷形成机理的基础上,分析了近50年来干热河谷植被恢复的研究进展与现状,阐述了元江县多年来实施干热河谷造林的历史进程,提出了在干热河谷造林的方法。     

武定县干热河谷地区造林现状及发展对策

武定县干热河谷地区包括东坡乡等7个乡镇1365．9km^2，由于立地条件差，气候干热，因此造林成活率低。自1999年以来，随着中德合作造林、天保工程、退耕还林工程的实施，其造林成活率达91．9％，保存率89％。文章总结了历年造林中成功的经验、失败的教训，认为采取良种壮苗、树种选择、集水保墒、适时造林、加强抚育等措施，干热河谷地区的造林会获得成功。     

元谋干热河谷退化荒坡、冲沟木豆造林技术

元谋干热河谷是我国典型的生态脆弱区,该区气候炎热干旱,植被退化严重,水土流失强烈,给造林工作增加了很大的困难。木豆根部具有根瘤,是干热河谷地区荒山、退耕还林地造林的优良树种。在对印度木豆多年适应性研究和木豆造林的实践经验基础上,总结了在该区域采用木豆进行造林的关键技术,即选择合适品种,采用鱼鳞坑或隔坡水平沟整地造林方式,施足底肥,直播造林,加强管理等。可为干热河谷区的造林提供参考。     

黄土高原森林植被水土保持机理研究

土壤侵蚀是造成环境退化的一个主要因素。长期以来因不合理的利用自然资源 ,日积月累的结果使得植被生存的环境受到极大的破坏 ,导致植被衰退 ,引发了严重的水土流失 ;水土流失的不断加剧 ,破坏了土地的生产力 ,土壤肥力降低 ,土壤蓄水能力减弱 ,植被生存的环境进一步恶化 ,如此以往使生态环境陷入恶性循环状态。黄土高原严重的水土流失与该区植被覆被率低有密切的关系。据“七五”统计 ,主要水土流失区现有森林面积约 2 5× 1 0 6ｈｍ2 ,其中人工林占 40 %左右 ,有林地森林覆盖率仅为 9 3% ,而且能发挥水土保持功能的森林覆被率仅为 7 0 %…     

晋西北黄土丘陵区4种植被类型土壤水分含量的变化特征研究

不同植被类型对于陆地生态系统的水分循环具有重要的调节作用。以晋西北黄土丘陵区偏关县境内的小叶杨林地、柠条林地、草地和撂荒地4种植被类型为研究对象,采用土钻法分别测定0～600cm不同土层的土壤水分含量,分析了晋西北不同植被类型的土壤水分含量的垂直分布特征及4种植被含水量的差异比较。结果表明：（1）在0—600cm土层中,平均土壤水分含量因植被类型不同表现显著差异（P〈0．05）,依次表现为小叶杨〉草地〉撂荒地〉柠条;（2）在0—600cm土层中,土壤水分含量随着土层深度的增加呈现先逐渐降低后趋于稳定的趋势,且同一植被类型不同土层深度间土壤水分含量差异显著（P〈0．05）,同一土层不同植被类型间的土壤水分含量也有显著差异（P〈0．05）;（3）研究区土壤剖面可分为易变层（0～100cm）、活跃层（100～200cm）、次活跃层（200—300em）和相对稳定层（300—600em）。在晋西北黄土丘陵区植被恢复中,应根据本区域土壤水分变化特点,选择适宜的植物种类,采取乔一草或乔一灌一草相结合的植被配置模式,以减少该区域土壤水分的过度消耗,这对于改善当地植被的生态效益具有重要意义。     

关于植物根系在土壤抗侵蚀和抗剪切中的作用研究进展

本文综合比较了不同种类土壤、不同植被和不同土层的土壤抗冲性的大小;根系通过改善土壤的理化性质来提高土壤的抗蚀性.活细根产生的分泌物和死根分解产物使土壤有机质含量增加,同时促进了土壤团聚体的形成,并且增加了土壤的孔隙度和渗透率;根系通过自身及根-土的相互作用来增强土壤的抗剪切能力.根系自身可以抵抗一定强度的拉力。大量的细根增加了土壤的接触面积,同时也增加了相互之间的摩擦力,乔木根系的主根和侧根在抗剪切中的作用也有所不同。     

青藏铁路沿线土壤有机碳含量变异特征分析

土壤有机碳是陆地碳库的重要组成部分,青藏高原作为全球的敏感区域,其土壤有机碳库的变化对研究全球变化具有重要意义。本研究选取青藏铁路格尔木至当雄段,设置20条样带177个样地,进行了实地调查,并对取回的土壤样品进行室内土壤理化性质分析,得到包括土壤有机碳含量、土壤pH值、海拔高度、土层厚度、土壤机械组成、土壤温度、植被盖度等在内的相关数据。采用方差分析和逐步回归分析的方法,分析了青藏铁路沿线的土壤有机碳含量与土层厚度、土壤pH值、海拔高度、土壤机械组成、土壤温度、植被盖度等因素的关系,结果表明,青藏铁路沿线土壤有机碳含量主要受到土壤pH值和植被盖度的影响。本研究为综合分析青藏铁路沿线土壤有机碳含量变化特征和进一步研究铁路运营对沿线环境影响提供了本底数据和重要依据。     

冶铅区植被变化及残留植物耐铅性特征研究

对江西莲花县冶铅区的植被变化和残留植物中耐铅性较高的植物的耐铅性特征研究表明:(1)耐铅性较强的植物是:夹竹桃、大青、商陆;(2)木本植物茎的韧皮部富铅最高,草本植物的叶和茎次之.不同器官富集铅的能力是:大青为茎韧皮部＞根＞叶＞茎木质部;夹竹桃为茎韧皮部＞根＞茎木质部＞叶.这两个树种的茎木质部和根的富铅性差异明显.夹竹桃的富铅速率在生长期前4个月最快. (3)冶铅区的铅污染主要分布在0～10 cm土层,很容易通过地表径流扩大污染范围,因此,在冶铅区污染严重的地段进行植被恢复时,应辅以工程措施,防止水土流失;同时采用须根系植物或扦插苗造林(侧根多,吸收面积增大),适当配置草本植物,这样有利于提高植被恢复和污染治理的效率.     

Edge effects on soil seed banks and understory vegetation in subtropical and tropical forests in Yunnan,SW China

Human-induced forest edges are common in many forest landscapes throughout the world. Forest management requires an understanding of their ecological consequences. This study addressed the responses of three ecological groups (non-forest species, secondary forest species and primary forest species) in edge soil seed banks and edge understory vegetation, and explored the relationship between the invasion of non-forest species in edge understory vegetation and the accumulation of their seeds in edge soil seed banks. The soil seed banks and understory vegetation were sampled along transects established at the edges of a continuous subtropical evergreen broad-leaved forest tract (Lithocarpus xylocarpus forest) bordering anthropogenic grasslands and three tropical seasonal rain forest fragments (Shorea wantianshuea forest) bordering fallows. Species composition in both soil seed banks and understory vegetation showed great difference among edge sites. In soil seed banks, the dominance (relative abundance and relative richness) of each ecological group did not change significantly along the edge to interior gradient. In understory vegetation, the invasion of non-forest species concentrated on the first several meters along the edge to interior gradient. The dominance of secondary forest species decreased with distance from the edge, while the dominance of primary forest species increased with distance from the edge. In forest edge zones, the invasion of a majority of non-forest species in understory vegetation lags behind the accumulation of their seeds in soil seed banks. Forest edges do not act as a good barrier for the penetration of non-forest species seeds. The lack of non-forest species in understory vegetation must then be due to conditions that are not appropriate for their establishment. Therefore, to prevent germination and survival of non-forest species further into the forest, management should focus on maintaining interior forest conditions.     

Assessing soil quality in a riparian buffer by testing organic matter fractions in central Iowa, USA

A multispecies riparian buffer strip (MRB) was established along Bear Creek in central Iowa by the Agroecology Issues Team at Iowa State University (ISU) in order to assess the ability of the MRB to positively impact soil erosion and process non-point source pollutants to improve water quality. Soil organic matter (SOM), and especially biologically-active soil organic matter, is considered to be an important soil quality indicator variable because of it has relationship to critical soil functions like erodibility and the capacity of the soil to act as an environmental buffer. The objectives of this study were to examine trends in SOM C accrual and to quantify intra-seasonal changes in SOM C and particulate organic matter (POM) C for each vegetation zone of a MRBS seven years after establishment on previously cultivated or heavily grazed soil. Total SOM C and POM C in soil under perennial vegetation (poplar, switchgrass and cool season grass) were significantly higher than under cropped soil. Total POM C changed within vegetation type over the four month study period, whereas total SOM C did not. After six growing seasons, SOM C increased 8.5% under poplar grown in association with cool season grass, and 8.6% under switchgrass. The results are very promising and suggest that changes in SOM C can occur in a relatively short time after the establishment of perennial vegetation in a MRB. These changes should increase the ability of MRB soil to process non-point source pollutants. This revised version was published online in June 2006 with corrections to the Cover Date.     

不同干扰条件下纳帕海湿地土壤种子库的特征研究

对不同干扰条件下纳帕海湿地植物土壤种子库物种组成、密度、多样性进行了研究,分析了地上植被与土壤种子库间的相似性关系。结果表明,纳帕海湖滨湿地土壤种子库物种在返青期有26个物种,在枯黄期有7个物种,蕨类植物仅在返青期生长。为旅游＋放牧干扰（Tr）;人工取草皮干扰（AR）和猪拱干扰（PF）3种干扰类型的土壤种子库中的植物物种数在返青期分别为21种、12种和12种;在枯黄期分别为2种、2种和6种。在返青期,1Tr和PF方式下土壤种子库的物种里多年生植物均高于1年生植物,只有AR方式下土壤种子库的物种为1年生植物高于多年生植物;在枯黄期,不同干扰方式下土壤种子库的物种1年生植物都均高于多年生植物,这是由于枯黄期的土壤中以当年产生的种子植物为主。不同时期和干扰方式下土壤种子库的物种为双子叶植物比例均明显高于单子叶植物,说明不同的干扰方式都使得单子叶植物减少。返青期和枯黄期种子库的总密度是PF〉TF〉AR;物种多样性在返青期是Tr〉AR〉PF,在枯黄期为AR〉PF〉Tr。在返青期,TT、AR、PF3种干扰下地上植被与土壤种子库物种组成相似性指数分别为0．53、0．30、0．44。因此,可以预测3种干扰后植物群落的恢复潜力是Tr〉AR〉PF。故在植被恢复的时候不仅要重视TT后的生态恢复,还要更加重视AR和,丌后的生态恢复。     

福建长汀河田水土流失地区的迳流试验及类芦的绿化效果分析

在福建长汀河田水土流失地区建立迳流小区，进行迳流试验研究，并以优良乡土草种——类芦为主栽草种进行快速绿化，以迳流试验分析其水土流失治理效果。经过两年的试验，获得了可靠的数据，收到了明显效果，类芦生长旺盛，植被覆盖率达90％以上，使治理区地表年迳流量减少31．2％，土壤年侵蚀量减少52％，严重的水土流失现象基本得到控制，生物多样性明显增加，绿化效果显著。类芦在水土流失地区的推广应用前景广阔。     

Impact of vegetation restoration on hydrological processes in the middle reaches of the Yellow River, China

Sediment discharge from the Yellow River originates mainly from the drainage area between Hekouzhen and Longmen, i.e., the Helong area. Spatial-temporal variations of the vegetation cover in this area during the 1981–2007 period have been investigated using GIMMS and SPOT VGT NDVI data. We have also analyzed the interannual variations in vegetation cover and changes in annual runoff and sediment discharge, the consequences from precipitation change and the Grain for Green Project (GGP). The results show that vegetation cover of the Helong area has increased during the 1981–2007 period. The northwestern part the Helong area, where the flat sandy lands are covered by grass, has experienced the largest increase. The region where the vegetation cover has declined is largely found in the southern and southeastern Helong area, which is a gullied hilly area or forested. Although precipita-tion was relatively low during the 1999–2007 period, the vegetation cover showed a significant increase in the Helong area, due to the implementation of the GGP. During this period, the most significant improvement in the vegetation cover occurred mainly in the gullied hilly areas of the Loess Plateau, such as the drainage basins of the Kuyehe and Tuweihe rivers and the middle and lower reaches of the Wudinghe and Yanhe rivers. A comparison of the average annual maximum NDVI between the earlier (1998–2002) stage and the next five years (2003–2007) of the GGP indicates that the areas with increases of 10% and 20% in NDVI account for 72.5% and 36.4% of the total area, respectively. Interannual variation of annual runoff and sediment discharge shows a declining trend, especially since the 1980s, when the decrease became very obvious. Compared with the 1950–1969 period, the average runoff during the 1980–2007 period was reduced by 34.8×108 m3 and the sediment discharge by 6.4×108 t, accounting for 49.4% and 64.9% of that in the 1950–1969 period, respectively. There is a positive correlation between the annual maximum NDVI and annual runoff and sediment discharge. This correlation was reversed since the implementation of the GGP in 1999 and vegetation cover in the He-long area has increased, associated with the decrease in runoff and sediment discharge. Less precipitation has been an important fac-tor driving the decrease in runoff and sediment discharge during 1999–2007. However, restoration and improvement of the vegetation cover may also have played a significant role in accelerating the decrease in annual runoff and sediment discharge by enhancing evapotranspiration and alleviating soil erosion.