隔坡梯田和隔坡复式梯田效益观测初报

本文从土壤的含水最、理化性质、渗透性、抗冲能力经济效益等多方面观测了隔坡梯田、隔坡复式梯田与一般水平梯田之间的差异，并阐述了它们的优势及使用范围，为发展经济林提出了较为理想的整地方式。     

杉木造林技术对于水土流失的作用分析

指出了随着我国水土流失和环境恶化现象越来越严重,许多学者与专家开始了对影响水土流失的因素进行分析,在这一过程中杉木造林技术的应用对于防治水土流失起到了良好的效果。从分析影响水土流失的因素入手,对杉木造林技术措施进行了探讨。     

水土流失立地下的绿竹栽培试验

选择2种水土流失严重的立地崩岗地和河边滩地进行绿竹栽培试验。试验结果表明,2种立地条件下,绿竹均能生长良好,母竹成活率、出笋率均在95％以上;绿竹在河边滩地的生长状况好于崩岗地。因此,绿竹可以作为治理水土流失的优良造林树种。     

梯田管理和深翻对山地椒园的影响

花椒是多年生植物,适应性强,可在山区、丘陵地广泛栽植,栽植后几十年生长在一个地方,它的生长发育和山地的土壤管理有很大关系。土壤的管理内容很多,包括水土保持、梯田管理、深翻熟化土壤、加厚土层、中耕除草等等,但在山地椒园中做的第一项工作是梯田管理和对土壤进行深翻。该文较详细地介绍梯田管理和土壤深翻的技术措施。     

水土流失区域胡枝子植被的形成及效益的初步探讨

论述在宁化县紫色土水土流失区域恢复胡枝子植被的措施及其效益,指出选择胡枝子作为先锋树种结合其它牧草植被是实现水土流失区域植被恢复的措施之一。     

对内蒙古黄河中游水土流失区生态环境治理工程的认识和实施建议

本文就内蒙古黄河中游水土流失区治理这一大型生态工程，在论述项目建设的必要性和意义的基础上，进而提出了全面规划，综合治理，集中连片，连续治理，植物措施与工程措施相结合，田间工程与蓄水保土耕作措施相结合，以小流域为单元进行综合治理，落实承包责任制，加强管护，坚持水土流失治理长期性，提高治理成功率和保存率的实施建议。     

哈尼梯田沟渠的植物多样性特征及其影响因素

哈尼梯田沟渠是一种具有湿地性质的人工溪流,是哈尼梯田可持续发展的关键所在。为探明哈尼梯田不同沟渠的植物多样性与环境因子的关系,以哈尼梯田典型灌区沟渠系统植物为研究对象,运用样方调查法、方差分析和冗余分析对不同类型沟渠的植被群落组成、物种多样性与环境因子的关联性进行分析。结果显示：(1)哈尼梯田沟渠植物共118种,隶属45科100属,以菊科和禾本科植物为主,占总种数的28.81%;植物生态型构成以湿生植物为主(52种),中生植物次之(42种);(2)不同沟渠植物Shannon-Wiener指数、Margalef指数和Simpson指数大致表现为三级沟渠>断头渠>二级沟渠>一级沟渠;Pielou指数则表现为二级沟渠>三级沟渠>一级沟渠>断头渠;(3)冗余分析表明干扰程度对哈尼梯田沟渠植物多样性的影响最为显著,其次为海拔和土壤有机碳,而土壤全氮、全磷、全钾、pH和积水深度对沟渠植物多样性的影响相对较小。哈尼梯田沟渠生境受人为干扰程度的影响最为强烈,适度的人为干扰有助于维持与提高沟渠植物群落多样性水平。该研究结果可为哈尼梯田沟渠植物资源保护和梯田生态系统健康...     

对内蒙古黄河中游水土流失区生态环境治理工程的认识和实施建议

针对内蒙古黄河中游水土流失区治理这一大型生态工程,在论述项目建设的必要性和意义的基础上,进而提出了全面规划,综合治理,集中连片,连续治理,植物措施与工程措施相结合,田间工程与蓄水保土耕作措施相结合,以小流域为单元进行综合治理,落实承包责任制,加强管护,坚持水土流失治理的长期性,提高治理成功率和保存率的实施建议。     

云南山区整地方式对水土流失的影响

坡耕地耕作方法的不同与水士流失量的多少密切相关。本文通过对几种常见的整地方式地表迳流量和泥沙流失量的实测表明,顺坡全垦种植造成的水土流失现象最为严重,而水平台地的水土流失量很小。对陡坡地必须退耕还林,将坡地改为台地,以控制山地水土流失,改善山区生态环境。     

Effects of contour hedgerows on water and soil conservation,crop productivity and nutrient budget for slope farmland in the Three Gorges Region (TGR) of China

Soil erosion has long been recognized as a major environmental problem in the Three Gorges Region (TGR) where slope farming is commonly practiced but the local topography is hilly. In consideration of the poor socioeconomic position of local farmers, low cost hedgerows had been introduced as a soil conservation measure to the TGR in the late 1980s. A collaborative research programme was initiated by the Chinese University of Hong Kong, the Chinese Academy of Science, the Huazhong Agricultural University, and the Bureau of Soil and Water Conservation of Zigui County to study the potential of adopting hedgerows in the TGR. Six experimental plots (10 m × 2 m, gradient = 25°) were constructed at Zigui County, Hubei Province to study effects of hedgerows on erosion, nutrient loss and crop productivity. Results indicated that there were significant relationships between rainfall and runoff, and rainfall and soil loss, respectively. Conventional slope farming could not be considered a sustainable agricultural practice because it resulted in severe erosion and low crop yield. Hedgerows per se seemed not to be effective in reducing soil loss and boosting crop productivity, but performances could be greatly improved when they combined with the use of fertilizers. Current farming and fertilization practices, however, generally did not meet N demands of crops. Results and findings of this paper will contribute towards a technical reference for the promotion and adoption of hedgerows in the TGR.     

Effect of vegetation and land use on soil fertility in Wutai Mountains of Shanxi Province

IntroductionSoilpropertiesdependonclimate,vegetationtypes,parentmaterials,landformandsoilderivedage(Bei-jingForestryCoIlege1982).VegetationpIaysasig-nificantroIeintheformationofsoiIparticuIarIyforthepropertiespfSurfBcesoil.PlantsabsorbselectivelynutrientfromsoilandbuiIdtheirbodies.ThenutrientpartofIitterdecomposedgradualIybymicrobeswouldraturntoground-TheroOtsystemOfplantaIsoplaysasignificantroleinsoiIproperties.EffectofpIantsonsoildependonthevegdstiontype,speciescomposi-tion,age,dens…     

Manganese in tree rings of Norway spruce as an indicator for soil chemical changes in the past

Element concentrations in tree rings can be used to monitor changes in environmental quality. With regard to the detection of incipient soil acidification, the manganese concentration in soils and plants is a significant marker for the switch of acid buffering in soils mainly with the exchange of base cations or with the dissolution of aluminium oxides. This is a site-specific non-linear event, indicating the onset of Al³⁺ dominance in the soil solution, were damages to vegetation due to acid stress become possible. This turning point is also a marker for the attainment of pH 4.2 in soils, the critical threshold used for critical load calculations. On a plot of the German environmental monitoring in forests the element concentrations in tree rings of 60-year-old spruces reveal a distinct decline in the Mn concentration, beginning in the late 1960s ending in the late 1970s. With this information it was possible to assume a base saturation in the soil of about 15–20% in the late 1960s, and to model the development of the base saturation of the site. A decline from 17.5 to 6% within one decade could be related to the deposition. This is in accordance with the base saturation of 6.5%, measured in 1993 for this site, but also for adjacent spruce sites on the same geological substrate. The knowledge of the time span were this site-specific non-linear event occurred is essential for the reconstruction of the soil chemistry of a site. Moreover, it enables the assignment of observations like ‘forest damages’ to the onset of changes in environmental quality.     

贵州西部水土流失现状及治理模式初探

对贵州西部毕节、六盘水等县(市)的水土流失状况进行分析,同时对该地区实施的各种治理模式进行调查。结果表明:岩溶石山区治理模式主要有全面封山育林植被自然恢复模式、人工促进封山育林植被恢复模式、生态移民模式、小流域综合治理模式;陡坡退耕地生物治理模式主要有林草结合模式、针阔混交模式、经济林模式、林竹模式。     

Mineral nutrition, soil factors and growth rates of Gmelina arborea plantations in the humid lowlands of northern Costa Rica

The purpose of this study was to determine the factors which are responsible for clearly visible growth irregularities in Gmelina arborea stands by relating growth rates to soil and site properties. All Gmelina plantations under study, established on degraded pasture soils in the Atlantic lowlands of Costa Rica, showed the same growth pattern: very poor growth and chlorotic foliage of trees in mid-slope positions, and fast growth and healthy leaves of trees on hilltops and hillbases. The variation in site and soil properties and tree growth rates was analysed, investigating 24 plots in eight different plantations. Leaf samples were taken from 120 trees (five trees per site). Foliar analysis revealed that the tree growth is highly dependent on the supply of N, P, K and S, indicating that poorly growing trees suffer from a multiple nutrient disorder. To identify the most restricting soil factor, simple correlations between growth rates and soil chemical and physical properties were applied to the entire data set. The best correlation was obtained with exchangeable soil K (r=0.78, P<0.001). Subdivision of the data set into plots on brown soils (eight) and plots on red soils (16) and subsequent correlation analysis resulted in much stronger relationships. Growth depressions in mid-slope positions had other causes on brown soils than on red soils. On the acid brown soils the combination of the variables Al saturation and bulk density could explain 82% of the variation of tree growth. Al saturation of up to 80% in brown soils inhibits nutrient uptake, particularly of N and P. The red soils dominate on Ca---Mg-enriched, alluvial terraces and were among the first soils to be cultivated in the region. During the agricultural use and at the establishment of the tree plantations, they received dolomitic lime to reduce Al toxicity. Here, very low K/Mg ratios (less than 0.03) may induce K deficiency. Therefore, the best multiple regression model for tree growth rates on red soils is obtained with K/Mg ratio and thickness of the humic A-layer (r²=0.75, P<0.001). Inclusion of the variable bulk density resulted in a clear improvement of the model, explaining 91% of the growth variability.     

大红山铁矿林草植被水土保持效益的研究

以裸地为对照,分别对土壤物理性状及土壤的渗透性,土壤中含水量的动态变化,地表径流及土壤流失量等进行了定点定量观测。研究结果表明,林地与草地能有效改善土壤物理性状、增强土壤渗透性和降低土壤水分含量;能通过提高土壤抗蚀性、改善土壤养分含量来充分发挥水土保持效益。研究结果还表明,林地和草地减少侵蚀效益较好,裸地的土壤流失最严重。与裸地相比,林地和草地对地表径流的控制率达到63%～89%,对土壤流失的控制率达到69%～94%。     

Protective effect of floor cover against soil erosion on steep slopes forested with <Emphasis Type="Italic">Chamaecyparis obtusa</Emphasis> (hinoki) and other species

 We evaluated the protective effects of floor cover against soil erosion in three types of forest located on steep slopes under a humid climate: 22- and 34-year-old Chamaecyparis obtusa (hinoki), 34-year-old Cryptomeria japonica (sugi), and 62-year-old Pinus densiflora (red pine) stands. We measured sediment transport rates (sediment mass passing through one meter of contour width per millimeter of rainfall), using sediment traps, before and after removing floor cover. Raindrop splash erosion was dominant in the experimental stands. Floor cover percentage (FCP) during the preremoval stage varied from 50% to 100% among the four stands, and sediment transport rates ranged from 0.0079 to 1.7 g m⁻¹ mm⁻¹. The rates increased to 1.5–5.6 g m⁻¹ mm⁻¹ immediately after removing floor cover, and remained high throughout the experiment. The presence of physical cover near the ground has a crucial effect on sediment transport on forested slopes. The protective effect ratio (the ratio of the sediment transport rate in a control plot to that in the removal plot) in a young hinoki stand, in which the FCP decreased markedly, was 0.3 at most, which is close to the rate for bare ground. The protective effect ratio in the red pine stand was ≤0.003. We concluded that the protective effect of floor cover in undisturbed forests in Japan differs by over two orders of magnitude, based on comparisons with previous studies. Received: March 11, 2002 / Accepted: August 16, 2002 Present address: Department of Forest Site Environment, Forestry and Forest Products Research Institute, Ibaraki 305-8687 Japan Tel. +81-298-73-3211; Fax +81-298-74-3720 e-mail: miura@affrc.go.jp Present address: Department of Forest Site Environment, Forestry and Forest Products Research Institute, Ibaraki 305-8687 Japan Tel. +81-298-73-3211; Fax +81-298-74-3720 e-mail: miura@affrc.go.jp Acknowledgments This study was supported by the Research Council of the Ministry of Agriculture, Forestry, and Fisheries, of Japan. We thank H. Ujihara, S. Ujihara, and M. Ogasawara in Otoyo, Kochi, who provided the experimental stands used in this study. We also thank K. Hirai, S. Kuramoto, E. Kodani, and the rest of the staff at the Shikoku Research Center, Forestry and Forest Products Research Institute, for their help in conducting the experiments. Correspondence to:S. Miura     

A combined rainfall simulator and tracer approach to assess the role of Best Management Practices in minimising sediment redistribution and loss in forests after harvesting

In this paper, we use the combined results from two contrasting methods to investigate the effectiveness of Best Management Practices (BMPs) on sediment erosion and redistribution in managed forestry environments in southeastern New South Wales (NSW), Australia. The first method employed a rainfall simulator at the skid track (snig track)—water bar (cross-bank)—general harvest area (GHA) spatial scale. This showed the majority of production and redistribution occurring from the skid tracks and coinciding with the period after initial disturbance. However, 5 years after harvesting, little redistribution between these elements was occurring. Furthermore, water bar structures were effective in trapping coarse sediment generated from skid tracks but markedly less so for fine <63 μm material. The second method involved constructing a tracer budget. This was based on measuring the ¹³⁷Cs content in each of the landscape elements of an entire watershed, which also enclosed a 5-year forest coupe selected for the simulator experiments. The ¹³⁷Cs budget effectively balanced with 61.1±4 and 59.2±4 MBq present prior to, and after, harvesting, respectively. Total recovery was 97±10%, which indicated no net loss of sediment from the study basin over the 6-year post-harvesting period within uncertainties. Of the total sediment redistribution, some 13±4% in losses occurred from the skid tracks and log landings, whilst net gains of 10±1% occurred in the GHA, filter strip and water bars. On a per unit area basis, the filter strip retained 8 times the ¹³⁷Cs and associated sediment of the GHA; however, the greatest overall trapping of fine sediment occurred in the GHA. Combining these two approaches suggests that management of filter areas is paramount, although the GHA remains the primary sediment buffer for the system. Greater effort to disconnect flow paths, retain roughness and reduce overland flow volumes in order to increase sediment deposition should occur here.     

浅议贵州森林分类经营及政策

本文通过对贵州省森林资源状况、结构和特点的分析,在研究森林分类经营现状的基础上,提出了贵州省未来森林分类经营目标和开展森林经营的政策措施。