民勤绿洲边缘植被恢复与重建初探

干旱缺水是导致民勤绿洲边缘植被退化的根本原因,也是民勤绿洲边缘退化植被恢复与重建的关键限制因子。恢复存在着一个过去时间的参照系,要恢复民勤绿洲边缘植被到过去某一时期的状态是不可能的;提取地下水灌溉恢复退化植被只能加速植被的进一步退化;采用滴灌灌溉目前还不具备条件;集流降水也于事无补;而目前尚无抗逆性更强的植物种用以取代退化植被。目前只能做到:⑴实施封育保护,使其进入退化→自然稀疏→沙丘活化→储存降水→自然演替的过程,使其形成在现有水资源条件下的植物群落或植被;⑵破坏土壤表面结皮,储存有限降水提高沙丘水分;⑶充分利用农田边缘和渠道渗漏剩余水;⑷农业节水是根本。     

论生态修复在水土保持生态建设中的优化作用

我国是世界上水土流失最严重的国家之一,水土流失是我国面临的头号环境问题。实施水土保持生态修复工程,是人们遵循自然规律,依靠自然本身的功能恢复植被,加快防治水土流失步伐的重大举措。从水土保持生态修复的涵义、原理出发,着重论述了生态修复在水土保持生态建设中的优化作用     

Rehabilitation of degraded lands by means of fallowing in a semi-arid area of northern Nigeria

Land degradation in semi-arid regions of Nigeria is a very serious problem and therefore rehabilitation of degraded lands is essential. This article reports the results of an investigation which was carried out to assess the extent to which fallowing rehabilitates degraded lands in a semi-arid area in northern Nigeria. An inferential approach was used which involved side-by-side comparison of plots located within an area of uniform climatic, geologic and geomorphic characteristics, but which have been under fallow for different periods of time (2, 5, 10 or 15 years). Using a systematic sampling procedure, topsoil and subsoil samples were collected from each of the fallow plots and also from a plot under a plant community of well over 80 years of age which was chosen to serve as the control (fairly natural vegetation). The extent to which the land of each fallow plot had been rehabilitated could be assessed by comparison with the condition of the control plot. The samples were analysed for texture, bulk density, water-stable aggregates greater than 0.50 mm, moisture content, organic matter, pH, cation exchange capacity (CEC), total nitrogen, available phosphorus and exchangeable bases. An analysis of variance (ANOVA) technique was used to test for significant differences amongst the fallow plots, while Student's t-test was used to compare the mean values of the soil properties of the control with the same properties under each of the fallow plots. The results obtained varied considerably, but in general it was observed that there were decreases in the coarsening of soil texture and bulk density, but increases in other soil properties with increases in the length of the fallow period. However, the changes were generally found to be more significant under the older fallows (10 and 15 years) than under the newer fallows (2 and 5 years). The causes of these trends and their implication for sustainable land development in the area are discussed. It is concluded that for land rehabilitation to be effective in this area, either fallow times must be quite long, or ways of improving the soil's recuperative capacities under short-term fallow should be sought.     

Condition of rehabilitated coal mines in the Hunter Valley,Australia

Legislation requiring the rehabilitation of new opencast coal mines came into effect in New South Wales, Australia, in 1973. Mining companies now stockpile original topsoil which is later spread with fertilizer over re-shaped overburden and waste carbonaceous material. Problems in successfully revegetating new surfaces are exacerbated by the thinness and infertility of natural soils, which are deficient in phosphorus and moderately acid. Revegetation has not been successful on untreated mine waste and overburden. This study provides a general overview of some aspects of post-rehabilitation soil chemistry and vegetation on these soils. A limited number of samples, collected from three mine sites having different rainfall and varying ages of rehabilitated areas, were tested for pH, EC, organic carbon, total phosphorus and available aluminium. Rehabilitated areas were all characterised by very low levels of total phosphorus, neutral pH, and variable and relatively low organic carbon, and some showed aluminium toxicity. Heavy application of gypsum at one of the steeper sites was associated with acid pH, high EC values, low total P, Al toxicity, some soil erosion and little plant cover. Except for this site, the variable vegetation cover at the sites studied seemed adequate for long-term re-establishment, despite serious weed invasion at some non-studied sites, soil loss on newly re-formed surfaces, and generally poor natural and rehabilitated soils.     

红树植物半人工小群落的生态学研究——不间伐的灌木环境对乔木种群的适宜度及群落改造决策

采用种群保存及生长指标综合指数,以间伐灌木后引进的乔木种群作为对照标准,以直接引进的乔木种群作为主要研究对象,进行不作间伐的灌木环境对于乔木种群的适宜度对比分析;再运用灰色局势决策理论和方法,以乔木种群优势和良好的林相、尽快发挥防风消浪效果、改造后所形成的半人工小群落合理的乔灌比例和最大的生产力、合理的乔木种群结构、群落的可持续性更新和长期发挥效益等方面进行多目标综合决策,从中选出了改造我国普遍存在的次生桐花树＋角果木灌木群落的较好乔木树种和确定较佳的改造方式。结果表明：不作任何间伐的灌木环境对三个乔木种群的适宜度大小依次为：红海榄＞木榄＞海莲;相对于直接引进方式而言,块状间伐灌木后引进乔木种群的改造方式可明显提高乔木种群的保存和生长发育效果;以直接引进乔木种群的方式改造桐花树＋角果木灌木群落,按乔木种群的优劣次序可排列为：红海榄→红树→木榄→海莲。     

宁夏中部干旱风沙区生态环境的演变与修复研究

宁夏中部干旱风沙区是我国北部生态环境严重恶化的地区之一。在综述宁夏中部地区生态环境历史演变的基础上,论述了生态环境的演变趋势,分析了生态环境退化及问题产生的原因,认为生态环境严重退化的宁夏中部地区,必须在人类的干预和引导下,使生态环境得以修复,并提出生态环境修复的七项对策。     

四海之腧取穴法结合康复训练治疗中风后足内翻临床观察

目的 探讨四海之腧取穴法结合康复训练应用于缺血性中风恢复期患者的临床效果。方法 抽取本院60例缺血性中风恢复期足内翻患者,随机分为治疗组和对照组,每组各30例,对照组进行常规取穴法结合康复训练,治疗组采用四海之腧取穴法结合康复训练,观察两组3个月后患者的Fugl-meyer运动功能评分、足内翻积分和Brunnstrom下肢功能分期的变化。结果 两组患者的Fugl-meyer运动功能评分较治疗前显著增加（P<0.01）,且治疗组治疗后较对照组明显升高,差异有统计学意义（P<0.01）。两组患者足内翻积分治疗后均有明显改善（P<0.01）,且治疗后治疗组与对照组比较,差异有统计学意义（P<0.01）。两组治疗后Brunnstrom下肢功能分期均较治疗前显著恢复（P<0.05）,且治疗组与对照组比较,差异有统计学意义（P<0.05）。结论 两种治疗方法在治疗中风后足内翻方面都有一定的效果,但是四海之腧取穴法结合康复训练治疗的临床疗效更明显,值得临床推广。     

我国热带南亚热带石质岩溶山地植被恢复研究现状与展望

我国热带南亚热带石质岩溶山地植被恢复与生态重建一直是国土整治的难点。文章论述了热带南亚热带地区石质岩溶的分布和植被特点,探讨了其植被恢复与生态重建的可行性;评述了我国热带南亚热带地区石质岩溶山地植被恢复和生态重建的研究现状;据此提出了未来需优先发展的研究领域,为我国热带南亚热带石质岩溶山区的生态环境建设和社会经济可持续发展提供依据。     

Estimated Forest Ecological Water Requirements in the Jinghe Watershed—Theory and Case Study

The ecological water requirement of forests is defined as the water resources used to maintain and improve the natural balance of forest ecosystems, which can be expressed by evapotranspiration of trees during the growing season. The relationship of evapotranspiration and soil moisture of forestland with tree growth showed that, if the soil moisture was above the temporary wilting point or the point of growth retardation, the growth of trees can, respectively, be basically or normally sustained. Therefore, they can be taken as the minimum and the suitable ecological water requirements of the forest. These points can be estimated by introducing the soil factor (K _s) and tree species factor (K _t) to potential evapotranspiration with the Penman formula. With geographic information system (GIS), the ecological water requirement for forests in the Jinghe watershed, western China was estimated. The results revealed that the minimum and suitable ecological water requirements of the forests in the Jinghe watershed were approximately 204×10⁷ and 340×10⁷ m³, respectively. Translated from Journal of Soil and Water Conservation, 2004, 18(6) (in Chinese)     

稻田生态系统健康修复：低纬高原区生态工程实践*

水稻不仅是我国最主要的粮食作物,而且水稻生产确保了全球粮食安全。但长期以来由于对水稻高产要求的不断提高,生产过程中化学物质的投入也在不断增加,导致稻作系统的生态安全和环境健康逐步成为突出的科学问题和公众关注的焦点。因此,从可持续生产战略的角度审视水稻生产模式和稻田生态系统健康的研究及其修复,对水稻生产具有重要意义。本文主要围绕低纬高原稻作区生态系统健康现状和成因、重要的生态工程修复实践案例,系统总结了稻田生态工程修复的主要技术与方法,为稻田生态系统健康修复提供可资借鉴的有效途径和生产策略。