Geomorphic estimates of the stability of a uranium mill tailings containment cover: Nabarlek,Northern Territory,Australia

The geomorphic stability of the cover (cap) over the pit of Nabarlek Uranium Mine in Arnhem Land, Northern Australia, is important because radon gas and other long-lived radio-nuclides arising from mill tailings must be contained for long periods. The primary agents of denudation in the region's seasonally wet tropical environment of low relief are rainwash, overland flow, rilling and gullying. Other agents of erosion are of less concern, although biogenic agents of erosion (e.g. termites and windthrow) may enhance fluvial activity. A combination of modelling, using the Universal Soil Loss Equation, and analogue estimates of denudation and thresholds of rilling and gullying from areas with similar geology, topography and climate are used to estimate the stability of the Nabarlek cover. Denudation rates are conservatively estimated at less than 100mm ky⁻¹. It is suggested that with some minor design modifications the cover will retain its integrity for several thousand years.     

Assessing soil erosion after fire and rehabilitation treatments in NW Spain: Performance of rusle and revised Morgan–Morgan–Finney models

Although the Revised Universal Soil Loss Equation (RUSLE) and the revised Morgan–Morgan–Finney (MMF) are well‐known models, not much information is available as regards their suitability in predicting post‐fire soil erosion in forest soils. The lack of information is even more pronounced as regards post‐fire rehabilitation treatments. This study compared the soil erosion predicted by the RUSLE and the revised MMF model with the observed values of soil losses, for the first year following fire, in two burned areas in NW of Spain with different levels of fire severity. The applicability of both models to estimate soil losses after three rehabilitation treatments applied in a severely burned area was also tested. The MMF model presented reasonable accuracy in the predictions while the RUSLE clearly overestimated the observed erosion rates. When the R and C factors obtained by the RUSLE formulation were multiplied by 0·7 and 0.865, respectively, the efficiency of the equation improved. Both models showed their capability to be used as operational tools to help managers to determine action priorities in areas of high risk of degradation by erosion after fire. Copyright © 2010 John Wiley & Sons, Ltd.     

南方灌区工程水毁的特点、原因和修复对策

１９９８年的特大洪水给湖南、湖北等省的灌区工程造成严重毁坏,其中以渠道、渠系建筑物和圩堤工程水毁最为严重。除了暴雨超常、洪水组合恶劣等自然因素之外,渠道防洪设施缺乏、圩区盲目垦殖、工程建设标准偏低、设计不当、施工控制不严是造成灌区工程水毁的几个主要原因,也是水毁工程修复和重建过程中应引起重视的几个问题。     

农村污染缓流水体的修复研究

农村缓流水体是维系乡村生态平衡的重要组成部分, 水质污染已成为国内乡村缓流水体普遍现状。讨论了农村缓流水体的污染成因，并以水生植物大漂为水体修复主体，进行了大漂的水体修复特性的试验，讨论了在可控条件下用大漂对缓流污染水体进行修复治理的植物修复技术及大漂在水体修复中可能带来的生态风险及其防范。     

农业活动对景观格局的影响

景观格局是自然和人类共同作用的结果,并随着经济发展和人口增长,农业活动在景观格局中起着愈来愈大的作用。放牧过程导致土壤退化和生物群落的不稳定,间歇式放牧会提高物种丰富度,促进生态系统的进化;植树造林不但有利于生态恢复和重建,而且对经济建设有巨大作用,更是保护生物多样性的手段;农作物种植包括物理干扰和化学干扰过程,改变了微生物的活性,同时对土壤性质产生影响;土地整理是人为的、强制性、时效性强的一种干扰,能在短期内对生态系统及景观格局产生剧烈影响,通过调整景观结构、改善景观破碎化,改变农业土地利用结构,使得社会效益、生态效益和环境效益均有所增加     

Using the RUSLE to identify factors controlling erosion rates of mine soils

Observable differences in particle size, smoothness and compaction between cap site (slope 2·8 per cent) and batter site (slope 20·7 per cent) surfaces on the waste rock dump at Ranger Uranium Mine were quantified in terms of revised universal soil loss equation (RUSLE) parameter values. Cap site surface material had a K_m (erodibility corrected for sediment density) of 0·030 and batter site surface material had a K_m of 0·0056. Using these K_m values (derived from particle size distributions), slope length and steepness (LS) factors of 0·36 for the cap site and 3·66 for the batter site, and a cover (C) factor of 0·45 for the cap site and 0·16 for the batter site, the RUSLE predicts an erosion rate from the cap site that is 1·9 times greater than erosion from the much steeper batter site. The RUSLE indicates that the finer particle size and blocky soil structure of the cap site (D₅₀ = 0·91 mm) compared with the looser granular structure of the batter site (D₅₀ = 1·74 mm) strongly influence erosion. The predictions are similar to observed soil losses from erosion plots on these sites under rainfall simulation events, for which the measured erosion rate from the cap site was approximately twice that from the batter site. For the RUSLE to predict the observed erosion rates, the support practice (P) factor for the cap site would have to be approximately 30 per cent greater than the P factor for the batter site. The higher cap site P factor probably results from smoothing and compaction caused by vehicle movement across the surface. Compaction is considered to have greatly reduced infiltration capacity, thus increasing the erodibility of the cap site. Vehicles probably also crushed the surface material at the cap site, creating the observed finer particle size distribution and further increasing the erodibility. Compaction, through its effects on erodibility (K_m) and surface roughness (P), is concluded to be the major cause of higher erosion from the cap site, even though the slope steepness is 10 times less. Parameterisation of the RUSLE quantifies the differences between sites and explains the unexpected erosion rates observed. The results highlight the need for careful management of rehabilitated sites to avoid increases in erosion which may arise from compaction by machinery.     

贡嘎山旅游景区泥石流灾害及减灾对策

采用文献资料法和理论分析法,探讨了矿区沉陷地复垦与生态重建的若干问题,目的在于提高矿区环境治理投资效果,促进矿区可持续发展.构建了矿区沉陷地复垦与生态重建的主要理论、关键技术和投资效果评价方法.最后指出,矿区沉陷地环境治理中,应将土地复垦与生态重建相结合.     

Offsetting global CO2 emissions by restoration of degraded soils and intensification of world agriculture and forestry

Increase in atmospheric concentration of CO₂ from 285 parts per million by volume (ppmv) in 1850 to 370 ppm in 2000 is attributed to emissions of 270 ± 30 Pg carbon (C) from fossil fuel combustion and 136 ± 55 Pg C by land‐use change. Present levels of anthropogenic emissions involve 6·3 Pg C by fossil fuel emissions and 1·8 Pg C by land‐use change. Out of the historic loss of terrestrial C pool of 136 ± 55 Pg, 78 ± 12 Pg is due to depletion of soil organic carbon (SOC) pool comprising 26 ± 9 Pg due to accelerated soil erosion. A large proportion of the historic SOC lost can be resequestered by enhancing the SOC pool through converting to an appropriate land use and adopting recommended management practices (RMPs). The strategy is to return biomass to the soil in excess of the mineralization capacity through restoration of degraded/desertified soils and intensification of agricultural and forestry lands. Technological options for agricultural intensification include conservation tillage and residue mulching, integrated nutrient management, crop rotations involving cover crops, practices which enhance the efficiency of water, plant nutrients and energy use, improved pasture and tree species, controlled grazing, and judicious use of inptus. The potential of SOC sequestration is estimated at 1–2 Pg C yr⁻¹ for the world, 0·3–0·6 Pg C yr⁻¹ for Asia, 0·2–0·5 Pg C yr⁻¹ for Africa and 0·1–0·3 Pg C yr⁻¹ for North and Central America and South America, 0·1–0·3 Pg C yr⁻¹ for Europe and 0·1–0·2 Pg C yr⁻¹ for Oceania. Soil C sequestration is a win–win strategy; it enhances productivity, improves environment moderation capacity, and mitigates global warming. Copyright © 2003 John Wiley & Sons, Ltd.     

山毛豆、木豆、猪屎豆在高速公路边坡生态恢复工程中的应用

山毛豆、木豆、猪屎豆这三种灌木耐旱耐瘠、抗逆性强、根系发达、枝叶繁茂、生长迅速,可涵养水土,提高地力。在云南元磨、思小等高速公路边坡生态恢复中的应用结果表明:以山毛豆、木豆、猪屎豆这三种灌木为主进行绿化,所形成的植物群落较稳定,绿化护坡效果好,对干旱、风沙等的抗逆性强,特别适用于热带、亚热带公路、堤坝的边坡水土保持及生态恢复工程。     

山西省实施封禁治理的做法与效果

水土保持综合治理中的封禁治理 ,是恢复生态、改善环境最有效、最快捷的办法。近年来山西省在封禁治理中进行的探索与实践 ,已取得良好的社会效果 ,促进了社会生产力的发展和生产关系的调整 ,引发了一系列深刻的变化。封禁治理需要一定的扶持资金作为保障 ,须建立起高素质的科技服务体系