植树种草是改善生态环境的治本途径

我们党和政府十分重视西北地区生态环境的保护和建设。江泽民总书记1997年8月就对西北地区治理水土流失、改善生态环境的调查报告作出“再造一个山川秀美的西北地区”的重要批示。朱基总理去年10月在甘肃考察时再次强调,切实加强生态环境保护和建设,是实施西部地区大开...     

伊克昭盟境内水土流失及风沙现状分析和治理对策

１伊克昭盟概况１．１地形伊克昭盟（以下简称伊盟）地处鄂尔多斯高原，总面积８．６万ｋｍ２。东、西、北三面为黄河环绕，海拔在１０００～１５００ｍ之间。地质构造简单，地层平缓，南部和西部沉陷地区多丘陵，东部是黄土丘陵沟壑区域，北半部为长达４００ｋｍ的库布齐...     

辽宁废弃矿厂植被恢复技术

矿产资源的无序开采,导致山区、林区植被与环境被严重破坏,恢复植被成为当务之急。应正确选择、配置树种,下大力气整理矿坑,挖掘坑穴,填换好土,严格挑选苗木,植苗前修根、浸根、蘸生根剂,植后浇水、覆盖,及时防病虫害。     

城市公共绿地建设中植树与种草对城市生态的效益比较

近年来，许多城市公共绿地建设中营造了大量的草坪，针对这种情况，本文以广州为研究对象从城市公共绿地建设的生态效益，经济效益的角度进行了比较，提出在城市公共绿地建设中不宜“以草代树”。     

朝阳地区风沙危害及治理对策

论述了朝阳地区风沙状况及造成的危害程度。并对如何治理风沙危害,提出了切实可行的对策。     

水土流失的危害与森林的作用

“水”和“土”是人类生息的重要资源，水土流失已成为威胁我们生存和发展的一个重要问题，该文用事实证明了山西省水土流失的现状，指出水土流失的危害，及森林在控制水土流失中的作用。     

朝阳地区风沙危害及治理对策

风沙危害是朝阳市的主要自然灾害之一,严重威胁、困扰生态环境和经济建设,直接影响人们的生产生活。该文分析了朝阳地区的风沙危害,并提出具体的治理对策,改善朝阳地区的生态环境和生产条件,加快经济建设,提高人民的生活水平。     

浅析北京延庆康庄风沙危害区造林技术

荒漠化已成为威胁人类生存与发展的主要问题之一。北京市延庆县康庄地区是风沙进入北京的咽喉要道之一,康庄风沙危害区治理工程取得了显著的成效。文章主要从整地、选择造林树种、栽植、先进技术的应用以及后期抚育管理等方面介绍了康庄风沙危害区的造林技术。     

重视开发建设区水土流失做好恢复植被的工作

通过对开发建设中水土流失现象的分析，找出造成这一现象的根本原因是植被遭到了严重的破坏，因此，认为恢复植被是治理开发建设区水土流失的关键，并进一步说明在开发建设区恢复植被过程中需要把握的一些技术问题。     

玛曲高寒草原风沙危害及其综合治理模式

对玛曲高寒草原风沙危害的类型、危害程度和治理技术模式进行了调查研究.认为玛曲高寒草原风沙危害主要有:导致土壤肥力降低、草原生产能力下降、草原生物多样性降低、对当地居民生活和家畜危害、增加黄河泥沙量等五个方面.针对不同类型沙化草原和危害方式提出了具体的治理技术模式,包括流沙治理的“封育+固沙+人工补播”模式,孤立沙丘全覆...     

油桐林地水土流失控制技术探讨

传统耕作方式造成了油桐林地水土流失,引起林地肥力降低,通过间种多年生浅根性经济树种和豆科草类,实现油桐林地免耕,采用人工方法截断地表径流控制水土流失,达到改善油桐林地生态环境的目的。     

Hydraulic redistribution of soil water by neotropical savanna trees

The magnitude and direction of water transport by the roots of eight dominant Brazilian savanna (Cerrado) woody species were determined with a heat pulse system that allowed bidirectional measurements of sap flow. The patterns of sap flow observed during the dry season in species with dimorphic root systems were consistent with the occurrence of hydraulic redistribution of soil water, the movement of water from moist to drier regions of the soil profile via plant roots. In these species, shallow roots exhibited positive sap flow (from the soil into the plant) during the day and negative sap flow (from the plant into the soil) during the night. Sap flow in the taproots was positive throughout the 24-h period. Diel fluctuations in soil water potential, with maximum values occurring at night, provided evidence for partial rewetting of upper soil layers by water released from shallow roots. In other species, shallow roots exhibited negative sap flow during both the day and night, indicating that hydraulic redistribution was occurring continuously. A third sap flow pattern was observed at the end of the dry season after a heavy rainfall event when sap flow became negative in the taproot, and positive in the small roots, indicating movement of water from upper soil layers into shallow roots, and then into taproots and deeper soil layers. Experimental manipulations employed to evaluate the response of hydraulic redistribution to changes in plant and environmental conditions included watering the soil surface above shallow roots, decreasing transpiration by covering the plant and cutting roots where probes were inserted. Natural and manipulated patterns of sap flow in roots and stems were consistent with passive movement of water toward competing sinks in the soil and plant. Because dry shallow soil layers were often a stronger sink than the shoot, we suggest that the presence of a dimorphic root system in deciduous species may play a role in facilitating leaf expansion near the end of the dry season when the soil surrounding shallow lateral roots is still dry.     

坡地种葛控制土壤水土流失技术研究

为探索坡地水土保持技术,以传统习惯种植作物为对照,开展了坡地种葛对减少水土流失技术的研究。结果表明:种植葛根可以有效地减少坡地土壤的地表径流量和土壤侵蚀量,种葛4年后地表径流量比对照减少一半以上;随着种葛年限的增加,土壤侵蚀量逐年降低。种葛第2年后,雨水对坡地土壤的侵蚀量比对照减少了58.0%,到第10年种葛处理的土壤侵蚀量比对照减少了91.1%。本研究通过对坡度在28°以内的坡地种葛,对减轻水土流失,改善土壤理化性状,培肥地力提供了一条新的有效技术途径。     

The response of planted trees to vegetation zonation and soil redox potential in created wetlands

We examined interrelationships among natural vegetation zones, soil redox potential (Eh), and metrics of tree seedling performance (i.e survival, growth, and photosynthesis) for planted Fraxinus pennsylvanica, Acer saccharinum, Quercus palustris, and Quercus bicolor at two created perched wetlands (two years and five years old) in Michigan, USA. Vegetation zones apparently associated with hydrology were fully developed at both sites. Wetland zones always had lower mean Eh than upland zones, indicating mostly anaerobic and aerobic root environments, respectively. Eh values for transition zones were similar to aerobic upland zones at the five-year-old site, and changed from anaerobic to aerobic conditions over the growing season at the two-year-old site. At the five-year-old site, transition zone trees of all species generally had greater height growth, survival, and were less likely browsed by deer than upland trees. They also had much greater survival and endured shorter periods of anoxia stress than wetland trees. Photosynthesis was positively related to survival and Eh, suggesting that unfavorable carbon balance may help explain low survival in the anoxic wetland zone. Management implications include: (1) vegetation zonation is a good indicator of wetland hydrological factors important to planted tree performance; (2) targeting developed transition vegetation zones for tree planting could increase the success and efficiency of efforts to create forested wetlands; and (3) transition zones extended over only a 9.3 cm vertical elevation gradient, indicating the importance of precise grading when creating perched forested wetlands.     

楚雄市三街镇水土流失现状及防治措施

楚雄市三街镇总面积２０５０３ｈｍ２，而水土流失面积为１３４２ｈｍ２，占６５．５％，造成水土流失的原因，有地形、地质、土壤、植被、降雨筹自然因素，也有森林植被遭破坏、陡坡开垦、过度放牧、采煤挖路筹人为因素。由于水土流失造成降低土壤肥力、淤积河道、泥沙覆盖农田，以及山体塌方、滑坡筹灾害。提出了今后的防治措施。     

Effect of shading,mulching and vegetation control on Douglas-Fir seedling growth and soil water supply

Harsh environmental conditions on many harvested sites in southwest Oregon necessitate site modifications for successful regeneration of Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco]. We conducted a 2-year study with 350 seedlings to assess the effects of twelve soil-shading, mulching, and vegetation control techniques on seedling growth and soil temperature and moisture environments. Treatments modified a variety of environmental conditions. Major effects of treatments were to lower soil surface temperature, reduce soil surface evaporation, and reduce vegetative competition for soil water. These modified conditions affected seedlings by adjusting the timing of seedling growth and reducing soil water loss to increase available water for seedling use. Final seedling shoot volume and stem diameter both differed among treatments. Seedlings in treatments where competing vegetation was controlled showed significantly greater growth than seedlings in other treatments. Soil water loss in treatments where either soil surface evaporation was controlled by mulching, or where competing vegetation was controlled, was significantly less than water loss from the shaded and control treatments. Soil water loss in treatments with vegetation controlled by herbicide was significantly less than in treatments with vegetation controlled by scalping. Seedlings showed greatest growth with treatments that elicited the most efficient use of available microsite water either by reducing soil surface evaporation or vegetation competition.     

实施退耕还林还草的实践与思考

山西省乡宁县把退耕还林还草作为在市场经济条件下农业领域的一场深刻革命 ,因此采取各种措施 ,强化科技支撑 ,立足于生态改善和农民的增产、增收 ,因地制宜植树种草。在县委的领导下 ,退耕还林还草工作深入开展。     

应用生物措施治理阜新县水土流失问题的探讨

形成水土流失原因是植被稀少、地势不平、降水集中、干旱少雨,治理必须采取生物措施才能根治。要全面规划,因地制宜,综合治理,要分坡位、坡形进行带、片、网,乔、灌、草结合全面治理。     

Change in soil macrofauna and vegetation when fast-growing trees are planted on savanna soils

Many forest species can be found in understory vegetation of old plantation plots, despite the fact that the native vegetation was a poor savanna growing on highly nonfertile sandy soils. The aim of the present paper is to describe the changes that occur in the environmental conditions when savanna is planted with fast-growing trees, and is particularly concerned with vegetation and soil macrofauna. The study was carried out in industrial eucalyptus plantations, and in experimental Acacia and pine plantations. Most plots were located on sandy soil, but some measurements were also carried out on clay soil planted with the same species in order to assess the influence of soil type.

A strong correlation was shown between the age of the eucalyptus trees and the percentage of forest species in undergrowth, emphasizing the progressive change from savanna vegetation towards forest vegetation.

Biomass and density of macrofauna were very low in both sandy and clayey savanna soils, total biomass being 3.3 and 5.8 g/m² respectively. Soil macrofauna became more important as the age of plantations increased, and biomass reached 29 g/m² in the 20-year-old eucalyptus plot on sandy soil, and 74 g/m² in 26-year-old eucalyptus plantation on clay soil, compared to 33 g/m² in the natural forest plot on sandy soil; however, frequency of occurrence and number of taxa were lower in old eucalyptus plot as compared to forest. Large differences in the abundance of macrofauna were observed in relation to planted species. Acacia was most favourable to soil macrofauna, with a total biomass of 60 g/m² on sandy soil and many taxa present. Pine plantations had a poor macrofauna and several taxa were lacking, particularly in the sandy soil.

Total macrofauna frequency was significantly correlated with the percentage of forest species in understory vegetation. Both were correlated with soil pH and soil organic-matter content. The results suggest that soil organic matter and litter quality are of main importance in changing the above- and below-ground habitat in plantations.     

关于退耕还林还草工程的几个政策性问题

退耕还林还草工程复杂 ,要保证实效 ,应在编制工程总体规划、补助政策等方面下功夫。经济林和生态林比例问题上 ,应以生态林为主 ,在市场前景好的前提下 ,适当提高经济林比重。种苗补助方式应采取林业部门组织统一供应苗本的方式。在生态环境恶劣、生存条件极差的地方 ,应考虑实行生态移民政策。