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干旱半干旱沙区人工植被与土壤水分环境相互作用关系研究进展 总被引：5，自引：2，他引：5
土壤水分在干旱、半干旱沙区人工植被恢复、植物生长和群落演替过程中起着重要作用。文中综述了我国主要沙化地区人工固沙植被土壤水分状况和动态的研究现状, 分析了土壤水分的时空格局及其影响因子; 探讨植被冠层、生物结皮、植物根系对土壤水分的调控作用和影响机理以及干旱、半干旱沙区人工植被土壤水分空间异质性及相关问题; 最后提出人工植被区的土壤水分动态模拟预测、土壤—植被—大气系统水量平衡和水分循环以及空间尺度扩展等问题应是未来的研究重点。 相似文献
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The pattern of precipitation,including precipitation amount,frequency and intensity,may change in the future according to the prediction of climate change.In arid zones,the soil dynamics, plant growth and vegetation change,desertification and hydrology might be affected by precipitation change.In general,the precipitation in extreme arid zone and arid zone showed an increase tendency whereas the precipitation in some area in semi-arid zone and sub-humid arid zone showed a decrease tendency.The increase of precipitation could enhance the growth of biological soil crust,improve soil water status,promote plant growth,increase vegetation coverage,facilitate the change from desert vegetation to grassland vegetation,and it is benefit to the reversion of land desertification.In addition,the increase of precipitation could also increase the river runoff,lake storage and promote the occurrence of flood,while the decrease of precipitation has the adverse effect.These studies will benefit the prediction of the possible response of ecosystem processes to the potential change of precipitation pattern in arid zones in the future,and it is important to the conservation of natural vegetation and the control of desertification.More field experiments and studies should be conducted in the future,including the effect of increased precipitation or temperature,nitrogen deposition and CO2 on soil,vegetation,desertification and hydrology of arid zones,so as the more persuasive results could be obtained from these experiments and studies. 相似文献
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水分是干旱区的主要限制因子之一,降水是干旱区最重要的水分来源。根据气候变化研究的预测,未来我国干旱区的降水格局会改变,包括降水量、降水频率和降水强度等。降水变化会影响干旱区的土壤变化,植被变化,土地荒漠化和水文变化等方面。我国极端干旱区和干旱区的降水有总体增加趋势,而部分半干旱区和亚湿润干旱区的降水则出现减少趋势。降水的增加能够促进生物土壤结皮的发育,改善土壤水分状况,促进植物生长,提高植被盖度,促使荒漠植被向草原植被方向发展,有利于土地荒漠化的逆转;另外,降水增加会增加河流的径流量和湖泊水量,促进洪水的发生,降水减少则具有相反的效应。这些研究有助于人们预测干旱区在未来降水格局改变之后可能发生的变化,对于天然植被保育以及荒漠化防治等实践工作等具有重要的理论指导意义。未来的研究需要加强实验,如增雨、升温、模拟氮沉降和CO2浓度增加等对干旱区的土壤、植被、荒漠化和水文等方面的影响,才能获得更有说服力的结果。 相似文献
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降雨对干旱半干旱地区土壤微生物影响研究进展 总被引：1，自引：0，他引：1
未来气候变化预示着降雨时间和数量的变化。降雨是干旱半干旱地区最重要的水分来源,降雨格局的变化将直接影响该区域生态系统的稳定性,而土壤微生物作为敏感指标多用来监测生态系统的稳定性。文中综述了降雨对干旱半干旱地区土壤微生物生物量、多样性的直接影响,以及其通过改变土壤水分、土壤空气和植被生长等对土壤微生物产生的间接影响,其中还可能伴随着其他因素的干扰,如土地利用方式、温度、海拔等。通过了解降雨格局变化对干旱半干旱地区土壤微生物的影响,可以更好地预测未来气候变化对该地区生态稳定性的影响。指出了降雨对干旱半干旱地区土壤微生物影响研究中存在的问题,并对未来研究进行了展望。 相似文献
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Comparative growth performance of some multipurpose trees and shrubs grown at Machakos,Kenya 总被引：3，自引：0，他引：3
Growth rates of 29 multipurpose trees grown in an agroforestry arboretum for six years at a sub-humid to semi-arid climatic
zone are presented. Exotic species such as Grevillea robusta, Sesbania grandiflora, Leucaena leucocephala, Cassia siamea and Sesbania sesban, some of which were outside their traditional climatic zones, had higher diameters, heights and bole volumes/tree (upto 130%
more in certain cases) than of the indigenous species. However, poor performance of several species (both exotic and indigenous)
would limit their agroforestry potentials at the evaluation site or other similar areas. 相似文献
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我国干旱半干旱地区干旱少雨，地表植被稀疏。然而，具有广泛生态适应性的微生物仍可通过生理代谢活动改变沙土的理化性质，促进土壤形成及植物营养转化，有利于植物生长，在区域荒漠化防治过程中起到重要作用，具有重要的生态学研究意义。文中总结我国干旱半干旱区土壤微生物的空间及季节分布特征，并对影响其分布特征的自然和人为因素进行全面梳理。了解土壤微生物的分布特征及其影响因素，可为土壤微生物在该区域生态恢复方面的应用提供参考。同时，根据区域生态恢复重建及增强区域生态安全保障的需要，对未来研究进行展望。 相似文献
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Chimène Fanta Abib Mama Ntoupka Régis Peltier Jean-Michel Harmand Philippe Thaler 《Agroforestry Systems》2013,87(2):427-438
Gum arabic production from Acacia senegal is lower in sub-humid areas than arid areas. Water stress is thought to be the reason for higher yields in arid areas. The application of ethephon is thought to mimic the effect of water stress in other plants. The objective of this study was to determine if the application of ethephon would increase the gum yields of Acacia senegal under sub-humid conditions in Cameroon. Trees receiving 40 or 120 mg ethephon were compared to controls in field experiments at a semi-arid and a sub-humid location in Northern Cameroon, over two seasons. Two provenances from drier areas (Sudan) were compared to the local one. In the first season, gum yield of the local provenance treated with ethephon was increased by 400–600 % compared to the untreated trees. Gum yield at the semi-arid location was 77, 313 and 214 g/tree with 0, 40 and 120 mg ethephon/tree, respectively, while at the sub-humid location, it was 30, 186 and 114 g/tree with 0, 40 and 120 mg ethephon/tree. However, in the second season, the effect of ethephon was not significant in the semi-arid area, whereas it was evident in the sub-humid area (up to 478 g/tree). Moreover, ethephon did not affect gum yield of provenances from drier areas (Sudan). This showed that the water-stress hypothesis has to be refined. The development of ethephon-based tapping systems is promising, but requires further studies with a wider range of environmental conditions and A. senegal provenances. 相似文献
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Mansour Karkon Varnosfaderani Rasoul Kharazmi Aliakbar Nazari Samani Mohammad Reza Rahdari Seid Hamid Matinkhah Nasrollah Aslinezhad 《林业研究》2017,28(1):145-153
The status of woody plants in dry-land systems is a fundamental determinant of key ecosystem processes. Monitoring of this status plays an important role in understanding the dynamics of woody plants in arid and semi-arid ecosystems. The present study determined the dynamism of the Zagros forests in Iran using Remote Sensing and Geographic Information System techniques and statistical science. The results show that the density of trees varied from 10 to 53 % according to the physiographic and climatic conditions of semi-arid regions. The best and lowest correlation between vegetation indices and forest density were obtained for the global environmental monitoring index (GEMI; R 2 = 0.94) and soil adjust vegetation index (R 2 = 0.81), respectively. GEMI is used to monitor land use changes over a 10-year period. Results show that 2720 ha2 of forest have been destroyed by human interference and tillage on steep slopes during this period which also resulted in the loss of the fertile soil layer. GEMI determined the areas with a biomass of trees and could normally separate border regions with low biomass density of trees from regions without canopy cover. The results revealed that assessment of forest and vegetation cover in arid and semi-arid arduous forest regions using satellite digital numbers and ordinary sampling is subject to uncertainty. A stratified grouping procedure should be established to increase the accuracy of assessment. 相似文献
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LU Qi YANG Youlin WANG Sen WU Bo REN Guoyu JU HongboNational Research Development Center for Combating DesertificationChinese Academy of Forestry. Beijing . ChinaAsia Regional Coordinating Unit. Secretariat of the UNCCD. Bangkok . Thailand Pacific Forestry Center. Canadian Forest Service. Natural Resources Canada West Burnside Road. Victoria. BC. Canada VZ M National Climate Center of China Meteorological Administration. Beiiine . China 《中国林业科技(英文版)》2003,(4)
Serious land degradation exists in the marginal areas of North China, the important ecological transition between semi-arid and sub-humid climate zones, which is a relatively narrow belt with 100-250 km in width and about 2 000 km in length. The annual rainfall varies between 300-400 mm. In the past hundred years (before 2000), most of the land in the region had been used for grazing and dryland cropping. As land-use is intensifying, particularly since 1970s and 1980s, desertification has accelerated. Our case studies in 2000 indicated that: (1) Sand-dust storms are the result of a combination of climate change, such as strong winds and dry weather, but their frequency and intensity are mainly related to precipitation variations. The El Nina/El Nino effect is strongly implicated. (2) Human economic activities result in sufficient sand-dust sources to create a hazard. Large-scale land conversion for cropping, deforestation, irrational use of water resources and over-exploitation of groundwater have all c 相似文献
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Conservation and restoration of degraded ecosystems in arid and semi-arid areas of northwest China 总被引：1，自引：0，他引：1
In “West Development” of China, one of the most important activities is the Natural Forest Protection Program, designed to
swiftly convert the focus of management and utilization of the natural forests from a timber orientation towards forest conservation,
sustainable management and environmental protection. The project covered almost all the arid and semi-arid regions in Northwest
region. Accompanying this great campaign this paper studied the conservation and restoration model of degraded ecosystems
in arid and semi-arid lands in Northwest China. The past practices have resulted in considerably natural forest degradation
and loss through land conversion (primarily for agriculture), over-harvesting, inadequate reforestation and lack of protection.
The consequences have been the loss of soil and water resources, diminished timber production capacity on a sustainable basis,
and environmental losses. This paper applied Aronson’s restoration model and proposed the conservation, restoration, re-allocation
and preservation program for the implementation of environmental improvement and natural forest conservation. 相似文献
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我国干旱、半干旱沙区广泛采用种植植物的措施固定流沙,因其可以更持久地、可持续地发挥防护效能。固沙植物以多年生灌木、半灌木和草本植物为主,不仅可以良好地适应当地的自然条件,而且具有较高的生态经济价值。研究优良固沙植物的饲用价值、绿化价值以及药用价值,对合理开发利用沙区植物资源具有非常重要的意义。文中回顾了我国不同优良固沙植物的资源分布情况,综述了沙区植物资源利用概况,包括沙质地区固沙植物的饲料资源、绿化资源以及药用资源利用,探讨了我国固沙植物资源利用过程中的不合理现象及存在问题,提出固沙植物资源的可行性保护措施,为充分发挥沙区植物资源防风固沙、水土保持的生态效益以及最大限度地提高当地的经济效益提供参考。 相似文献
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对中国森林区划的新探讨 总被引：2，自引：0，他引：2
以往对中国森林的区划,主要是从林区管理和经营的角度来考虑的。本文对此进行了新的探索,即从森林生态系统的角度来对中国森林进行区划,提出了依照基带地带性理论来区划中国森林。以气候区带为大框架,强调森林的植被型、植被群系组以及包括野生动植物种在内的森林生态系统的完整性而不受行政区域的割裂影响。提出了气候区域下的森林区划7个分区的方案,这种区划方案不仅是对中国森林区划的一种新的探索,也对当前我国森林生态系统自然保护区体系的建设和管理有着实际的指导意义。 相似文献
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本文总结国内外矿区植被恢复研究进展,系统提出阜新矿区植被恢复限制性因子,并根据该区特点进行适宜生态复垦措施,建立稳定、高效人工生态系统,是治理阜新矿区废弃地有效对策。 相似文献
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Hu Jian-zhong 《中国林学(英文版)》2005,7(4):41-48
Seabuckthorn （Hippophae rhamnoides） planting areas in the three northern areas （north, northeast and northwest） of China are divided into five planting zones： the semi-humid forest prairie climate zone for ecological and economic types of seabuckthorn plantations in the southern part of the Loess Plateau; the semi-arid steppe climate zone for similar types of plantations in the central part of the Loess Plateau; the arid desert steppe climate zone for ecological type of seabuckthorn plantations in the northern part of the Loess Plateau; the semi-arid and semi-humid steppe climate zone again for ecological and economic types of plantations in northern Hebei and western Liaoning and the cold humid steppe climate zone for economic types of plantations in the northern part of northeast China. The aim of this demarcation is to avoid a random introduction of seabuckthorn. In each of the five zones, objectives should be set and suitable seabuckthorn species, subspecies and varieties should be planted according to site conditions, seed sources and methods of tree breeding. The cultivation centers, bases, stations, or units should be established and successful models of seedling and planting methods should be encouraged. The principle of matching trees with suitable site conditions and adjusting measures to local conditions should be practiced. From a strategic viewpoint of solving ecological and economic problems of seabuckthorn development in the three northern areas, every seabuckthorn center must have its own germplasm nursery, standard plantation for popularizing, excellent seed and seedling nurseries and sufficient afforestation areas for demonstration and propaganda purposes. These measures would improve the ecological environment and promote economic and social development in the three northern areas of China. 相似文献
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干旱区沙质土壤缺乏矿物质和有机胶体、漏水漏肥,是沙区植被修复和生态林业建设的主要障碍,与此同时随着生态建设和林草业的发展产生了大量的植物性有机废弃物。因此,回收利用林业剩余物,研发植物性节水保肥材料,改良干旱区风沙土,具有恢复退化土地和回收有机物料的双重意义。文中概述了植物性节水保肥材料在荒漠化防治特别是沙漠林业开发中的重要性,综述了植物性节水保肥材料种类和发展史,对比国内外研究和应用有机物料改良沙质土壤的趋势和特点,从林业剩余物利用和荒漠化防治等领域提出了研发建议。 相似文献
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Distribution and development strategy for Jatropha curcas L. in Yunnan Province, Southwest China 总被引：7，自引：0，他引：7
Yunnan Province is the main distributing area of Jatropha curcas L. This plant is abundant in several drainage areas of the dry-hot, dry-warm and sub-humid valleys in the south subtropical area of Yunnan Province. The seeds that were picked from trees blossoming between April and May and fructifying between September and October will have large seed yield and fine quality. For developing bio-diesel stock forest of J. curcas in areas with adaptive climate, seeding measures for afforestation should be taken and techniques on breeding, fast-growing, and high-yielding plantation cultivation are very important. 相似文献