[en] Some strategies for improving cost-effectiveness of wellsite reclamation programs were described. For example, pre-construction site assessments (PSA) are helpful in documenting soil and vegetation conditions prior to drilling. Data obtained in these assessments could be used to determine possible risk factors such as soil erosivity, chemical or textural concerns. Drilled and abandoned well sites can also provide useful tools for evaluating current construction practices. Equally important is to maintain communication with all parties responsible for the reclamation process including land agents, supervisors, reclamation contractors, landowners and the conservation and reclamation inspector. Some methods for dealing with the long-term storage of topsoil removed from the working area of an operating site were also described

[en] All earth dams require protection against erosion due to wave action on the upstream slope and protection against runoff from rain, snowmelt or wave splash on the downstream shell. Erosion protection is a major cost factor in embankment dams, typically varying from 5-15% of the dam cost, although it can approach 50% of embankment cost for long low dikes. The most common type of erosion protection is dumped rock riprap. Current practice in riprap design is based on rational analysis of factors affecting riprap stability, and the performance of existing riprap protection. Historical development of riprap design is reviewed, beginning with U.S. Army Corps of Engineers dams in the 1940s. Riprap design parameters are based on slope steepness and severity of wave action, which depends on reservoir geometry and location. A common cause of riprap deterioration is loss of underlying bedding as a result of inadequate design or segregation of riprap and bedding during construction. The most common form of riprap failures include: loss of filter material through riprap if it is too fine; inadequate rock size to resist wave action, resulting in beaching; segregation during construction, resulting in pockets of undersized rock which can expose the underlying filter, and pockets of oversized rock through which bedding can wash out; breakdown of poor quality stone due to prolonged exposure and wave action; and failure to extend the primary riprap far enough downslope to be below the level of wave action at low reservoir levels. 26 refs., 8 figs

[en] As we go into 2001, it is an opportune time to review the work of the Sub-programme in 2000 and to look ahead to the tasks and activities planned for 2001 and beyond. Two Research Co-ordination Meetings (RCMs) were held in 2000, one in Vienna and one in Tunis, Tunisia. The Vienna RCM was the first meeting of the ''acid soils'' Coordinated Research Project (CRP) while the Tunis RCM was the 2nd meeting of the ''rainfed'' CRP. A Consultants' meeting on ''Integrated Soil, Water and Nutrient Management for Sustainable Rice-Wheat Cropping Systems in Asia'' was held in FAO, Rome, to plan for a future CRP. FAO Headquarters staff from the Plant Production and Protection Division (AGP) and the Land and Water Development Division (AGL) as well as staff from Regional Offices in Asia participated fully in the meeting. A major event for the Sub-programme in 2000 was the FAO/IAEA International Symposium on ''Nuclear Techniques in Integrated Plant Nutrient, Water and Soil Management'' which is held in Vienna once every five years. Presentations were of a high standard and highlighted recent advances in the development and applications of nuclear techniques in agronomic and environmental studies. Four RCMs are planned for 2001. Final RCMs are scheduled for the ''organic matter'' CRP (Kuala Lumpur, Malaysia) and the ''soil erosion'' CRP (Vienna). The 2nd RCM of the ''agroforestry'' CRP and the 3rd RCM of the ''rainfed'' CRP will be held in Kuala Lumpur and Vienna, respectively. Initial contracts for the ''rice-wheat'' CRP will be awarded in 2001 with the first RCM to be held early in 2002 in Vienna in conjunction with a training workshop. A Consultants' Meeting on biological nitrogen fixation is being jointly organised with AGL in early 2001 in Rome and planning has already commenced for a half-day Symposium titled ''Towards integrated soil, water and nutrient management in cropping systems: the role of nuclear techniques'' to be held under the aegis of the 17th World Congress of Soil Science in Bangkok in 2002. The Sub-programme provided support to 22 Technical Co-operation Projects worth more than US $4 million during 1999-2000 compared with 23 projects in 1997-98. Four projects in the current biennium were regional and one was interregional. The projection for 2001-02 is 25 projects, including 3 regional and one interregional. Thus, the Subprogramme's portfolio of TC projects has remained relatively stable during the 1997-2002 period. The regional projects for 2001-02 include fertigation (Europe), desertification (Africa) and nutrient management (Asia). Sub-programme inputs to the FAO Medium Term Plan (2001-07) and to the IAEA and FAO Programmes of Work and Budget (2002-03 biennium) were finalised during 2000. Two new CRPs will commence in 2003. One project will be concerned with the practical application of the Cs-137 technique to assess soil conservation measures and the other is targeted at improved irrigation practices. Three TECDOCS and a range of articles were published by the Sub-programme in 2000, details of which can be found in the current and the previous Newsletters

[en] Short communication

[en] A study was conducted to evaluate sand dune plants in order to determine which plant species have the potential to naturally establish and grow in oil sand tailings near Fort McMurray, Alberta. In this study the seeds and roots of eight species of psammophilous plants, native to the local boreal ecosystem, were collected and tested for growth in tailings sands under controlled conditions. Four species (Astragalus aboriginum, Stellaria arenicola, Salix brachycarpa, and Deschampsia mackenzieana) germinated over 70 per cent of the initial germination tests. All four species survived well in field trials in the first growing season. It was concluded that each of the four primary species had potential use in revegetating oil sands tailings. 5 refs., 4 tabs

[en] One of the key elements of sustainable cropping systems is the integration of crops and/or crop cultivars with high tolerance of soil acidity and which make most efficient use of the nutrients supplied by soil and fertilizer. This paper is based mainly on on-going work within an EU-funded project combining basic research on plant adaptation mechanisms by plant physiologists, and field experimentation on acid soils in Brazil, Cameroon, Colombia and Guadeloupe by breeders, soil scientists and a agronomists. The results suggest that large genetic variability exists in adaptation of plants to acid soils. A range of morphological and physiological plant characteristics contribute to tolerance of acid soils, elucidation of which has contributed to the development of rapid techniques for screening for tolerance. Incorporation of acid-soil-tolerant species and cultivars into cropping systems contributes to improved nutrient efficiency overall, and thus reduces fertilizer needs. This may help to minimize maintenance applications of fertiliser through various pathways: (i) deeper root growth resulting in more-efficient uptake of nutrients from the sub-soil and less leaching, (ii) more biomass production resulting in less seepage and less leaching, with more intensive nutrient cycling, maintenance of higher soil organic-matter content, and, consequently, less erosion owing to better soil protection by vegetation and mulch. (author)

[en] Physical models were tested in a wind tunnel to determine optimum surface-ravel admixtures for protecting silt-loam soil from erosion by, wind and saltating, sand stresses. The tests were performed to support the development of a natural-material surface barrier for and waste sites. Plans call for a 2-m deep silt-loam soil reservoir to retain infiltrating water from rainfall and snowmelt. The objective of the study was to develop a gravel admixture that would produce an erosion-resistant surface layer during, periods of extended dry climatic stress. Thus, tests were performed using simulated surfaces representing dry, unvegetated conditions present just after construction, after a wildfire, or during an extended drought. Surfaces were prepared using silt-loam soil mixed with various grades of sand and Travel. Wind-induced surface shear stresses were controlled over the test surfaces, as were saltating, sand mass flow rates and intensities. Tests were performed at wind speeds that approximated and exceeded local 100-year peak gust intensities. Surface armors produced by pea gravel admixtures were shown to provide the best protection from wind and saltating sand stresses. Compared with unprotected silt-loam surfaces, armored surfaces reduced erosion rates by more than 96%. Based in part on wind tunnel results, a pea gravel admixture of 15% will be added to the top 1 in of soil in a prototype barrier under construction in 1994. Field tests are planned at the prototype site to provide data for comparison with wind tunnel results

[en] A general review of the measures involved in restoring abandoned access road sites in British Columbia was presented. Permits and licences are needed for the use of crown land for roads used by the petroleum and natural gas industry for exploration activities. However, the regulatory framework for road site reclamation is not well developed. The nature of access road reclamation is very site-specific. Some of the issues that are considered for all reclamation projects include slope stability, water control, revegetation, soil rehabilitation, access management and monitoring. The primary objective of reclaiming access road sites is to return the site to conditions that are equal or better than pre-disturbance conditions. Restoration measures must be approved by BC Environment and by the Department of Fisheries and Oceans where federal fisheries responsibilities are involved. 54 refs., 5 tabs., 3 figs

[en] Careful selection of crop species, among other aspects, is very helpful in enhancing energy production by way of increased biomass yields from agricultural land. A wide range of C₃ and C₄ plant species has been introduced and investigated for their environmental and climatic impact. The results indicate already that some perennial C₄ crop species posses high yield potential, lower erosion-index, better CO₂ reduction rates and need less fertiliser, water and chemicals. (Author)

[en] This study attempts to describe, interpret and analyze, in depth, the varied geomorphological hazards and their impacts prevailing in the swat valley locate in the northern hilly and mountainous regions of Pakistan. The hills and mountains re zones of high geomorphological activity with rapid rates of weathering, active tectonic activities, abundant precipitation, rapid runoff and heavy sediment transport. Due to the varied topography, lithology, steep slope, erodible soil, heavy winter snowfall and intensive rainfall in the spring and summer seasons, several kinds of geomorphological hazards, such as geomorphic gravitational hazards, Fluvial hazards, Glacial hazards, Geo tectonic hazards, are occurring frequently in swat valley. Amongst them, geomorphic gravitational hazards, such as rock fall rock slide, debris slide mud flow avalanches, are major hazards in mountains and hills while fluvial hazards and sedimentation are mainly confined to the alluvial plain and lowlands of the valley. The Getechtonic hazards, on the other hand, have wide spread distribution in the valley the magnitude and occurrence of each king of hazard is thus, varied according to intensity of process and physical geographic environment. This paper discusses the type distribution and damage due to the various geomorphological hazards and their reduction treatments. The study would to be of particular importance and interest to both natural and social scientists, as well as planner, environmentalists and decision-makers for successful developmental interventions in the region. (author)