黄土高原植被生态恢复评价、问题与对策

以中国水土流失与生态安全综合科学考察西北黄土区考察组获得的资料为依据,对黄土高原植被恢复方面取得的成就、存在的问题和未来的发展策略进行综合评价分析.退耕还林和禁伐禁牧措施实施以来,黄土高原地区植被覆盖率、质量已经呈现稳定提升的势态,民众生态环境保护意识增强,植被恢复措施优化,多元化投资与城镇化发展使黄土高原植被恢复前景较好.目前存在的主要问题是:植被恢复投资力度不够;政策不稳定使农户无远期规划,政策不配套,使大户承包治理停滞;过分注重经济效益,人工经济林比例过大,生态功能不强;禁伐禁牧封禁措施缺乏技术支撑,许多重大理论问题亟待解决.未来植被恢复策略包括:明确不同时期植被恢复目标和完善恢复途径;保护现有成果,增加自然恢复和生态修复比例;用政策保护承包大户植被建设的积极性;加大植被建设和科研投资力度,培育黄土区植被恢复方面的科技创新能力.     

Effects of different vegetation restoration models on soil microbial biomass in eroded hilly Loess Plateau, China

Vegetation restoration is a key measure to improve the eco-environment in Loess Plateau, China. In order to find the effect of soil microbial biomass under different vegetation restoration models in this region, six trial sites located in Zhifanggou watershed were selected in this study. Results showed that soil microbial biomass, microbial respiration and physical and chemical properties increased apparently. After 30 years of vegetation restoration, soil microbial biomass C, N, P (SMBC, SMBN, SMBP) and microbial respiration, increased by 109.01%–144.22%, 34.17%–117.09%, 31.79%–79.94% and 26.78%–87.59% respectively, as compared with the farmland. However, metabolic quotient declined dramatically by 57.45%–77.49%. Effects of different models of vegetation restoration are different on improving the properties of soil. In general, mixed stands of Pinus tabulaeformis-Amorpha fruticosa and Robinia pseudoacacia-A. fruticosa had the most remarkable effect, followed by R. pseudoacacia and Caragana korshinkii, fallow land and P. tabulaeformis was the lowest. Restoration of mixed forest had greater effective than pure forest in eroded Hilly Loess Plateau. The significant relationships were observed among SMBC, SMBP, microbial respiration, and physical and chemical properties of soil. It was concluded that microbial biomass can be used as indicators of soil quality. __________ Translated from Journal of Natural Resources, 2007, 22(1): 20–27 [译自: 自然资源学报]     

黄土高原水土流失严重地区植被恢复策略分析

以晋西黄土高原地区为例，对黄土高原水土流失严重地区植被恢复的现状和前景进行了全面而细致的分析，提出土石山次生林区应实行“封山育林为主，辅之以人工措施”植被恢复策略。在土层浅薄、坡度较陡的生态脆弱地段，需要进行长期的植被封育；在土层深厚而且坡度平缓地段，可适当辅之以人工措施，包括人工抚育，以及补植或补造有经济价值的乡土树种等。当前土石山区次生林经营管理中急需解决的问题是提高林分质量，加强管护力度；黄土丘陵区应该实行封山禁牧或轮牧、围栏圈养以及陡坡地退耕等措施，这是植被恢复的前提和基础。同时，对黄土丘陵区恢复和建设森林植被的可能性进行了分析和探讨。最后指出只有转变农村传统的以破坏生态环境为代价的粗放生产经营方式，长期坚持植被封育和保护为主的策略，结合人工营造乡土树种为主的森林群落，晋西黄土高原地区才有可能恢复原来的森林植被景观，真正实现该地区的植被重建和水土流失的根治。     

Effect of conversion of farmland to forest or grassland on soil erosion intensity changes in Yanhe River Basin, Loess Plateau of China

Dynamic changes of soil erosion affected by conversion of farmland to forest or grassland in the Yanhe River Basin were analyzed based on the revised universal soil loss equation (RUSLE). The RUSLE variables were selected and calculated reasonably using the GIS technique. Results show that: 1) After the conversion of farmland to forest or grassland, soil erosion decreased greatly. Compared with soil erosion in period of 1986 to 1997, the soil erosion amount had been reduced on the average by 30.6% by 2000; 2) Of the different land uses, slope farmland, especially the steep slope land had the greatest impact on soil erosion. The conversion of forest or grassland was the main driving force for the reduction of soil erosion; 3) In the short term, soil erosion was mainly controlled by C-factor, implying that the adjustment of land use structure might be an effective approach to reduce soil erosion. __________ Translated from Science of Soil and Water Conversation, 2007, 5(4): 27–33 [译自: 中国水土保持科学]     

黄土高原退耕还林中的抗旱造林技术与应用研究进展

该文对黄土高原的地貌、植被情况以及退耕还林现状和退耕还林中存在的主要问题进行了论述，综合评述了退耕还林过程中所采取的抗旱造林技术措施，主要围绕抗旱造林树种的选择、蓄水保墒技术以及林分合理配置等三个方面进行阐述，并指出抗旱造林技术的研究应用及水源工程建设是今后退耕还林中研究的热点问题。     

黄土高原植被属性有关论点辨析

以黄土高原森林植被为重点,利用一定的论据讨论黄土无林论、草原次生论、厚层黄土观、400mm降水论、气候变迁论等立论的缺陷以及植被分区所存在的歧义。以排它法表明以延安一线、长城沿线等为标志的植被地带性原则的合理性,认为黄土高原具有森林发育的地带性环境。     

黄土高原和六盘山区森林面积增加对产水量的影响

[目的]定量评价黄土高原地区造林对流域产水量的影响,指导林水协调的林业发展和森林管理。[方法]综合分析多年在黄土高原、泾河流域、六盘山区开展的森林产流影响的多尺度研究结果。[结果]在黄土高原区域尺度,林地平均年径流(16 mm)比非林地(39 mm)减少59%;在典型流域尺度(泾河干流上游流域),森林年均产水量(76 mm)比自然草地减少51%,其中,半湿润土石山区的森林年均产水量(88.8 mm)比自然草地减少58%;在典型小流域尺度(半湿润的香水河小流域),完全覆盖森林后的年均产流比无森林覆盖情景减少59%。森林增加导致的年产流减幅在干旱地区和干旱年份会更大,并可能超过100%,如年降水量低于450 mm的黄土流域、半干旱的泾河上游黄土区的林地及半干旱的叠叠沟小流域的坡面乔木林分样地,其年产水量常为零或负值,即需消耗土壤水分和坡上汇入径流等维持生存。低度间伐不能显著减少森林蒸散耗水。[结论]在黄土高原研究的小流域、流域和区域空间尺度内,造林减少年产流量的平均幅度都在50%~60%以上,且随干旱程度的增加可达到100%,并因消耗降水外的其他水源而出现负产流。需依据水分承载力合理选择待恢复植被类型和确定森林覆盖率,这是保障区域供水安全和实现林水协调管理的基本途径。     

Effects of landscape restoration on soil water storage and water use in the Loess Plateau Region,China

Large-scale vegetation restoration in China's Loess Plateau has been initiated by the central government for controlling soil and water losses in the past three decades. However, there is virtually no guidance for plant species selection for the restoration purpose. We investigated the effects of planting trees and shrubs, land-use conversions from croplands to pastures and native grasslands on soil water dynamics and water stresses by using long-term field measurements from 1986 to 1999 in the semi-arid loess hilly area. Our research has led to the following three major findings. Firstly, the amount of soil water storage within a 100 cm depth decreased as measured at both the beginning and the ending point of growing seasons regardless land cover types. The soil water replenishment by rainfall during rainy seasons was not sufficient to fully recharge the soil water storage. Landscape restoration through shrub planting may help retain more soil water than other land cover types. Secondly, the ratio of actual evapotranspiration (ET) and pan evaporation (PET) generally declined for all land cover types during the study period. Shrub lands had the largest ET/PET ratio, followed by native grassland, cropland/alfalfa, and pine woodland. The ET/PET ratio of native grasslands declined fastest, followed by pine woodlands, shrub lands, alfalfa, and croplands. Pine woodland's low ET/PET ratios were mainly caused by its higher runoff due to soil compaction resulted from soil desiccation. Lastly, we found that the soil water storage at the beginning of growing season was important in determining the ET/PET ratios. This study suggested that pine plantations may not be appropriate for landscape restoration in such a semi-arid loess hilly area while shrubs may be highly recommended.     

晋西黄土区不同森林植被的林地水源涵养功能

林地(包括枯落物层和土壤层)是森林植被水源涵养功能的主体,在水土保持中具有举足轻重的作用。根据蔡家川流域林地枯落物和土壤的分析与测定,研究比较了晋西黄土区不同森林植被的林地水源涵养功能。结果表明,不同植被类型枯落物的最大有效拦蓄量的大小排序为:虎榛子林(2 85mm)>沙棘林(2 38mm)>刺槐林(1 88mm)>油松×刺槐林(1 31mm)>油松林(0 77mm)。不同植被类型0～60cm土层的林地土壤最大拦蓄量为:虎榛子林(248 2mm)>油松×刺槐林(241 0mm)>刺槐林(210 2mm)>油松林(198 1mm)。晋西黄土区不同森林植被的林地水源涵养功能研究,为该区水土保持林的合理经营与利用提供了科学依据。     

黄土高原退耕还林试点地区现状调查与思考

退耕还林是实现西部生态环境重建的重要举措。在退耕还林试点地区进行的现状调查和研究对退耕还林工作的进一步开展具有重要意义。通过对陕西省吴旗县和安塞县的实地调查，就黄土高原试点地区取得的成绩及存在的问题进行了分析和探讨，并提出相关建议。     

甘肃黄土高原生态修复与重建战略思考

通过对甘肃黄土高原地区社会—经济—生态系统的科学考察,以实地调查资料和文献资料为依据,对甘肃黄土高原植被修复与重建的环境和理论基础综合分析,提出了物种选择及搭配、模式布局、植被建植和促进恢复等技术策略,以及生态规划尺度、社会运行机制、资源协调配置等政策导向,从而为甘肃黄土高原地区生态持续恢复,消除区域甚至全国生态退化提供帮助.     

Effects of forest vegetation on runoff and sediment transport of watershed in Loess area, west China

This paper aims to study the effects of vegetation on runoff and sediment transport at the watershed scale, and to provide a theoretical basis for afforestation in the Loess area, in the nested Caijiachuan watershed, Jixian County, Shanxi Province of west China. Forest watersheds and farmland watersheds with similar terrain features were selected through cluster analysis to study their runoff and sediment transport characteristics. Results showed that compared with farmland watersheds, runoff generation time in forest watersheds was delayed remarkably, and peak flow was reduced greatly, which indicates that vegetation played an important role in holding and absorbing rainfall. Besides, with the increase of forest coverage, the runoff amount, runoff depth and runoff coefficient decreased during the rainy seasons. The runoff depth and runoff coefficient of farmland watersheds in the rainy season were 5–20-fold as much as that of forest watersheds, and runoff and sediment yield of watersheds with low forest coverage were 2.7–2.9-fold and 3–6-fold as great as those with high coverage during rainstorms, and low forest coverage had larger variation in sediment hydrograph. For the complexity and scale dependence of the influence of forest vegetation on runoff, forest hydrological functions based on regional scale or watershed scale were worthy of further studies. __________ Translated from Science of Soil and Water Conservation, 2006, 4(3): 48–53 [译自: 中国水土保持科学]     

黄土区人工林草植被深层土壤干燥化研究进展

黄土高原地区深层土壤干燥化(土壤干层)是人工林草植被过度耗水导致土壤水分负平衡的结果。概述土壤干层的研究进展,包括土壤干层的特征、类型、量化指标、成因、分布、危害及其缓减对策,指出当前研究中存在的问题,对今后研究提出建议。     

黄土高原地区混交林建设的主要模式

针对目前黄土高原地区人工林建设中存在的纯林较多、森林群落稳定性较差等问题,提出了以混交林建设为核心、以综合抗旱措施为保障的黄土高原地区自然植被恢复的技术路线,对全国同类地区的林业生态建设具有较强的指导意义。     

Effects of soil drought on seedling growth and water metabolism of three common shrubs in Loess Plateau, Northwest China

The growth and water metabolism of three common shrubs on the Loess Plateau were studied under soil with different water contents. Results showed that water consumption of those species decreased with the increase in drought stress, and water consumptions of these shrubs were different: Forsythia suspensa was the greatest, and Syringa oblata was the lowest. The growth rate of new branches and leaf area of three species were the fastest under adequate soil water conditions, and were the lowest under severe drought. Under the same water conditions, the growth of F. suspensa was the fastest while that of S. oblata was the slowest. The water content, proline and chlorophyll content of different species changed with the increase in soil water stress. The leaf water content of Periploca sepium and F. suspensa was obviously higher than that of S. oblata, while the leaf proline content of F. suspensa and S. oblata was lower than that of P. sepium. The ratio leaf chlorophyll a: b of F. suspensa and S. oblata decreased with the decrease in soil water content. Although these three shrubs had different mechanisms in response to drought stress, they all had higher drought resistance and could adapt to the drought condition on the Loess Plateau. This paper provided some bases for choosing tree species on the Loess Plateau. __________ Translated from Acta Botanica Boreali-Occidentalia Sinica, 2007, 27(1): 91–97 [译自: 西北植物学报]     

海南省重点退耕还林区5年植被恢复调查与分析

为了解海南省退耕还林5年的植被恢复情况,对重点退耕还林区进行了植被恢复调查与分析。结果表明：海南省主要退耕还林模式以乔木纯林模式为主,如：橡胶、槟榔、按树和木麻黄等,但也有少量的其他退耕还林模式;各造林树种5年的保存率均达到国家规定的检查验收标准,其中橡胶树的保存率〉92％,显著高于其他树种;木麻黄与小叶桉生长速度显著高于橡胶与槟榔,5年郁闭度达到0．7-0．8,生态效益明显,但槟榔和橡胶生长速度较慢,郁闭度只有0．3-．4;退耕地草本生长茂盛,草本盖度与抚育频度和方法有关,无除草措施草本盖度可高达100％,有抚育措施草本的高度与盖度将会显著降低,过度控制草本的生长,将会严重影响退耕还林的生态功能。     

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.     

广东大宝山周边植被现状及矿区植被恢复重建

文章通过对广东韶关大宝山矿区及周边地区的实地调查,发现矿区现有植被类型以草丛和灌草丛为主,矿区周边则以自然次生常绿阔叶林、常绿和落叶阔叶混交林、毛竹林及各种人工林等为主;矿区土壤都呈强酸性,各土地类型土壤理化性状普遍偏差,重金属含量普遍偏高;针对矿区的这些植被和土壤特性,分别对采矿区、废矿区和排土场等提出相应的环境整治和植被恢复措施及树种选择,并为保障矿区造林成功率提出相应的高强度营林措施。     

Review on Soil Moisture of Plantation Land in the Loess Plateau

Water is a crucial factor restricting vegetation restorationand conservation in the Loess Plateau (Zhang Leiming,et al, 2002). Annual rainfall is relatively low there, andits distribution is uneven on both the space and thetime scale. Water can be re-distributed in soil as thesoil layer is very deep (Hu Liangju, et al, 2000). It isdry on the mountain ridge and hilltop, but wet in thevalley. The characteristics of soil water distributionmake it difficult to conserve eco-environment in theLoe…     

林地土壤水分模型SWUF在晋西黄土高原的适用性

采用EnviroSMART土壤水分定位监测系统于2008-05-14至2008-10-11及2009-05-05至2009-08-05对晋西黄土区刺槐人工林、油松人工林(水平条整地)、天然次生林0～150cm土层的土壤水分进行实时监测。以这些监测数据为基础,分析SWUF模型参数的敏感性,进行参数率定,验证SWUF模型在晋西黄土高原水土保持林地的适用性。结果表明:SWUF模型中的蒸发参数、产流参数、非饱和水流参数属于高度敏感性参数,使用SWUF时必须对这些参数进行率定;SWUF模型对刺槐人工林20～150cm各土层、油松人工林和次生林0～150cm各土层土壤水分动态模拟效果较好,模拟值与实测值相对误差在20%以内;SWUF适用于模拟油松人工林和天然次生林各土层每日土壤含水量,也能够比较充分地模拟3种林地不同深度土壤层土壤水分的日变化趋势,但在模拟耗水量大的刺槐林表层土壤水分方面还需要改进。