Soils of the Main Ethiopian Rift Valley escarpment: A transect study

The mountainous environment of the Ethiopian highlands has a great variety of ecotopes and thus demands great flexibility in land management. Different climatic conditions and landscape positions induce different soil forming processes, leading to various soil types with specific risks and potentials. The present study portrays a soil sequence of the central section of the Main Ethiopian Rift Valley, from the footslopes of the eastern escarpment to the marginal volcano structures. Six profiles under natural vegetation are described for classification according to the USDA Soil Taxonomy and World Reference Base for Soil Resources classification systems, and special site characteristics are discussed. The Acacia savannah of the footslopes (1900 m a. s. l.) is characterized by Vertisols (Mazic Vertisols/Aridic Haplusterts), with often pronounced effects of seasonal waterlogging. All other soils are well-drained and reflect the general increase in rainfall with elevation and slope, causing a decline in topsoil pH and a change from cation-rich clay soils of the Podocarpus-dominated forest at 2300 m a. s. l. (Mollic Nitisols/Typic Palehumults) to strongly-leached Humic Umbrisols/Humic Dystrudepts of the Hagenia-dominated forest around 2600 m a. s. l. The highland savannah plain (2700 m a. s. l.) with a drier and cooler environment has typically Mollic Cambisols/Dystric Haplustepts, which are less leached and have a rather brownish colour. At 2900 m a. s. l., Niti-umbric Alisols/Andic Hapludalfs are found in the Hypericum forest at the midslopes of the marginal volcanoes receiving high rainfall, whereas soil development is at a more initial state in the Erica-dominated forest at 3200 m a. s. l. (Umbric Andosols/Alic Hapludands). Clay mineral composition is kaolinite-dominated for the upper five profiles, with a high proportion of poorly crystalline components in the upper savannah and the volcano upslopes. The lowermost profile probably has a polygenetic origin indicated by an abrupt change from a smectitic to a kaolinitic composition in the subsoil. Soil development on quite homogeneous bedrock appears essentially controlled by relief and climate, underlining the suitability of the region as a model area for in-depth gradient studies on ecosystem processes and land use.     

Physiological Response of Daphnia magna to Linear Anionic Polyacrylamide: Ecological Implications for Receiving Waters

Linear anionic polyacrylamide (LA-PAM) is being considered as a soil amendment to reduce seepage and infiltration in unlined earthen canals. While polyacrylamides have been extensively used for potable water treatment, dewatering sewage sludge, coal and mine processing, paper manufacturing, and agriculture, little is known about its ecological impact to aquatic ecosystems. Acute toxicity (LC₅₀, 24 and 48 h) and chronic exposure tests (limited and continuous exposures) were conducted on Daphnia magna. In the chronic limited exposure experiments, Daphnia were exposed to LA-PAM for only 24 h whereas for the chronic continuous exposure the concentrations of 0, 0.5, 1, 5, 10, and 100 mg/L were tested and the endpoints of growth, onset to reproduction, fecundity, and mortality were measured for the duration of 32 days. There was no significant difference among the chronic, limitedly exposed organisms. The acute toxicity for LA-PAM was measured at 100, 150, 200, 250, and 300 mg/L. The acute test showed that the LC₅₀ for LA-PAM was at 152 mg/L. Overall in the chronic, continuous exposure test, D. magna was negatively impacted by LA-PAM at levels as low as 1 mg/L. Growth was reduced by 37% and 89% at 1 and 100 mg/L, respectively. Fecundity and onset to reproduction was impaired at 10 and 100 mg/L. Kinematic viscosity ranged from 0.98 cSt at 1 mg/L to 2.9 at 100 mg/L. At these levels, mechanical and physiological impairments due to the viscous properties of LA-PAM are the proposed mechanisms of reduction in the life history traits of D. magna.     

Systematically Investigated the Influences of Permeable Pavement Materials on the Water Quality of Runoff: Batch and Column Experiments

To investigate the effect of permeable pavement surface materials (PPSMs) on the influences of pollutant removal in urban storm runoff, six commonly used PPSMs (porous asphalt, porous concrete, cement brick, ceramic brick, sand base brick, and shale brick) were selected and the research was carried out by batch and column experiments. Results indicated that in batch experiments, except for the shale brick, most of the PPSM will release different pollutants continuously with the contact time increasing. Compared with other materials, porous asphalt and ceramic brick could increase the concentration of pollutants in the runoff greatly. With the contact time increased to 48 h, the concentration of NO₃-N and TN increased to 13.0 and 23.1 mg/L for ceramic brick and 13.3 and 32.3 mg/L for porous asphalt, respectively. This is mainly due to the artificial activity that accelerates the wear of the PPSM. Furthermore, results showed that PPSM could eliminate pollutants and influenced the removal efficiency greatly in column experiments. Most PPSMs have a noticeable purification effect on different pollutants, among them the purification effect of porous asphalt is the best. The concentrations of COD, NH₃-N, and TN are 139.6, 1.32, and 7.79 mg/L in the effluent, respectively. These results may be attributed to the relatively stable environment in column experiments which is more suitable for the removal of pollutants. This study could offer new insight into the transformation of pollutants in damaged PPSM and provide useful guidelines for the better design of permeable pavement system.

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Influence of Volcanic Ash Deposition on the Classification,Fertility, and Suitability of Some Soils of West Sarawak,Malaysia

Abstract

A study was conducted to determine the influence of the volcanic ash deposition on the physicochemical characteristics of some soils of West Sarawak and to evaluate their suitability for some common crops. A total of seven common soil series of different geology and locations from West Sarawak were collected and analyzed for their physicochemical and dissolution analysis. For comparison, similar analytical procedures were conducted on selected volcanic ash soils of Indonesia and the Philippines. The Sarawak soils were classified as Inceptisol, Ultisol, and Oxisol. The soils were acidic and had relatively low CEC and exchangeable bases. The other laboratory analysis, however, were not conclusive in the results. The soils were evaluated for crops such as rubber, oil palm, rice, pepper, banana and tapioca. Most of these soils were rated as moderate (S₂) to marginally suitable (S₃), indicating insignificant contribution of volcanic ash into the fertility status of soils of west Sarawak regions.     

三万年来卤阳湖湖泊沉积物地球化学元素变化特征及其环境意义

利用荧光光谱仪、等离子发射光谱,测定关中盆地卤阳湖区沉积物(0~280cm)元素含量变化,在光释光定年与R型聚类分析基础上,探讨3万年来该区26种元素的地球化学行为特征及环境意义。结果表明:卤阳湖沉积物元素大致可分4类:第1类Si、Zr、Hf、Na,指示4.6ka B.P.后湖泊萎缩,外源沉积减少;第2类Ga、U、Sr,指示4.6ka B.P.和2.0ka B.P.前后的湖区干旱气候;第3类Cu、Hg、Mn、Mg,指示4.6ka B.P.后湖水咸度的增加;第4类Ti、Sb、Pb、V、Th、Co、Fe、Bi、Cs、Zn、Ni、Rb、Ga、K、Al,这15种元素指示湖水咸度与周边人为活动的增加。元素变化特征说明,卤阳湖在33~10.4ka B.P.之间,沉积环境稳定,全新世前期(10.4~4.6ka B.P.)湖水变淡,4.6ka B.P.后,外源沉积减少,湖水咸度升高,在2.0ka B.P.前后,湖泊干旱造成大量盐分生成,之后,虽气候转湿,但人为活动增加使湖泊快速走向衰亡。     

Effects of Additional Layer(s) on the Mobility of Arsenic from Hydrothermally Altered Rock in Laboratory Column Experiments

Hydrothermally altered rocks are frequently encountered when tunnels are constructed in Hokkaido, Japan. High concentraions of hazardous elements, such as arsenic (As), are often released from these rocks into the surrounding environments. Therefore, the rocks are considered potentially hazardous waste. This article describes the effects of water content and oxygen (O₂) concentration in relation to additional layer(s), i.e., surface covering and bottom adsorption layers, on As leaching by using laboratory columns with water content and O₂ concentration sensors. The results show that the use of additional layer(s) has a significant effect on lowering As migration. This was due not only to the adsorption capacity of As by the adsorption layer but also to the water content and O₂ concentration inside the rock layer. The accumulation of pore water was increased in the rock layer in cases with additional layer(s), which resulted in lower O₂ concentration in the rock layer. Consequently, the leaching of As by the oxidation of As-bearing minerals in the rock layer was reduced. Moreover, a longer water-resident time in the rock layer may induce precipitation of Fe oxy-hydroxide/oxide. These results suggest that the geochemical conditions of the rock layer affect As leaching and migration.     

Stone bunds for soil conservation in the northern Ethiopian highlands: Impacts on soil fertility and crop yield

In the Ethiopian highlands, large-scale stone bund building programs are implemented to curb severe soil erosion. Development of soil fertility gradients is often mentioned as the major drawback of stone bund implementation, as it would result in a dramatic lowering of crop yield. Therefore, the objectives of this study are to assess soil fertility gradients on progressive terraces and their influence on crop yield, in order to evaluate the long-term sustainability of stone bunds in the Ethiopian Highlands.

The study was performed near Hagere Selam, Tigray and comprises (i) measurement of P_av, N_tot and C_org along the slope on 20 representative plots and (ii) crop response measurement on 143 plots. Results indicate that levels of P_av, N_tot and C_org in the plough layer are highly variable between plots and mainly determined by small-scale soil and environmental features, plot history and management. After correcting for this “plot effect” a significant relationship (p < 0.01) was found between the position in the plot relative to the stone bund and levels of P_av and N_tot, which are higher near the lower stone bund, especially on limestone parent material. For C_org and on basalt-derived soils in general no significant relationship was found. Although soil fertility gradients are present, they are not problematic and can be compensated by adapted soil management. Only in areas where a Calcaric or Calcic horizon is present at shallow depth, care should be taken. Crop Yields increased by 7% compared to the situation without stone bunds, if a land occupation of 8% by the structures is accounted for. Yield increased from 632 to 683 kg ha⁻¹ for cereals, from 501 to 556 kg ha⁻¹ (11%) for Eragrostis tef and from 335 to 351 kg ha⁻¹ for Cicer arietinum.

No negative effects reducing stone-bund sustainability were found in this study. Soil erosion on the other hand, poses a major threat to agricultural productivity. Stone bund implementation therefore is of vital importance in fighting desertification and establishing sustainable agriculture in the Ethiopian highlands.     

Phosphorus Response and Fertilizer Recommendations for Wheat Grown on Nitisols in the Central Ethiopian Highlands

The provision of farmers with proper and balanced fertilizer recommendations is becoming increasingly important, for reasons of crop productivity, food security, and sustainability. Phosphorus (P) response trials with wheat were conducted on Nitisols at 14 sites in the central Ethiopian highlands during the 2010 and 2011 cropping seasons. The treatments, comprising six levels of P fertilizer (0, 10, 20, 30, 40, and 50 kg P ha^?1), were arranged in a randomized complete block design with three replicates. Based on a yield difference between the control and the P treatments, 90% of sites responded to P fertilizer. Application of P fertilizer increased wheat grain yield, up to 30% more than the control. Extractable soil P concentrations (Bray 2, 0–15 cm deep) 3 weeks after planting significantly responded to P fertilizer rate. The critical P concentration (for 90% relative yield) was 13.5 mg kg^?1. Most sites tested had Bray 2 P values <10 mg kg^?1. In the absence of a soil test, a recommendation of 40 kg P ha^?1, resulting in the best response overall, could be made for the first year of application. We also recommend that to prevent a potential loss of wheat yield, a maintenance application of at least 5–12 kg P ha^?1 be applied every year, irrespective of the calculated recommended rate, in order to replace P exported from the field in produce. Further field trials are required to determine interactions between P response and the effects of climate, soil properties, and other management practices.     

Modeling and Evaluating the Performance of River Sediment on Immobilizing Arsenic from Hydrothermally Altered Rock in Laboratory Column Experiments with Hydrus-1D

Large volumes of excavated rock are produced as a result of road and railway tunnel construction in Hokkaido, Japan. Due to the geological condition of this region, these rocks have often undergone hydrothermal alterations, causing them to contain elevated amounts of hazardous elements including arsenic (As). Therefore, these excavated rocks are potentially hazardous waste, and proper disposal methods are required. In this article, performance of unsaturated river sediment on immobilizing As from hydrothermally altered rock is evaluated using laboratory column experiments and Hydrus-1D. The results reveal that the river sediment significantly reduces As migration. Arsenic retarded by river sediment was observed in three patterns. The first was an adsorption onto minerals originally contained in the river sediment. The next pattern was a combination of reduction of As generation by oxidation of As bearing-minerals, irreversible adsorption, and adsorption onto newly precipitated Fe oxy-hydroxide/oxide. The last pattern led to a further depletion of As leached from the rock layer due to a shift in the majority of the As generation mechanism from dissolution to oxidation in combination with a low concentration of oxygen in the rock layer. These patterns were satisfactorily evaluated by a Hydrus-1D model with reversible and irreversible adsorptions. The information from this work is effective in designing and establishing a reasonable technique for the disposal of hydrothermally altered rocks.     

水环境中有机磷农药生物标志物的研究进展

有机磷农药（OPs）的大量施用导致水环境的污染,影响到非靶生物特别是鱼类的生存。因此,需要对OPs进行快速、灵敏、准确监测,以便及时采取必要的措施。近二十年来,国内外学者在利用生物标志物监测水体OPs方面进行了大量研究。本文对这些生物标志物的分布、结构、特点及其对OPs的响应特征进行了综述,并提出了生物标志物监测水体OPs存在的问题及进一步研究的方向。     

不同种类微生物及其碳酸酐酶对土壤-灰岩系统钙镁锌元素迁移作用的土柱模拟实验研究

通过土柱模拟实验研究了筛选自西南岩溶区的典型细菌、真菌、放线菌对石灰岩的溶蚀动态及作用效果,并研究了这3种类群微生物及其碳酸酐酶(CA)对土壤-灰岩系统Ca、Mg、Zn元素迁移的影响。结果表明:①实验所用的典型细菌、真菌、放线菌均对石灰岩有较强的溶蚀作用,但是不同类群的微生物对石灰岩的溶蚀效果不同,溶蚀后石灰岩的表面形貌变化不同,其中,真菌的溶蚀效果最显著,放线菌和细菌次之;②典型细菌、真菌、放线菌对不同元素迁移的影响不同,对于Zn2 、Ca2 的迁移影响而言,真菌>放线菌>细菌>无菌对照组;对于Mg2 的迁移影响而言,细菌>真菌>放线菌>无菌对照组;③一定范围内温度增加对Ca、Mg、Zn3种元素的迁移有不同程度的促进作用;④土柱淋出液中CA平均活性与Ca、Mg、Zn3种元素的总淋失量之间存在一定的正相关关系,说明CA对这3种元素的迁移具有一定的影响,且因不同元素而异。本研究结果对于评价不同类群微生物在生物岩溶及岩溶系统元素迁移中的作用和地位提供了一定的科学依据。     

Factors Influencing the Quality of Dietary Proteins: Implications for Pulses

Protein content has been a leading trend in product development in recent years. Similarly, a growing desire for non‐animal‐based protein sources has led to an interest in plant‐based protein such as cereals and pulses. Pulses constitute the dried seeds of nonoilseed legume crops, including dried peas, chickpeas, beans, and lentils. Their crude protein content (typically 21–26% by weight) positions pulses as plant‐based alternatives to meats within international dietary guidelines. A major consideration with respect to the inclusion of pulses in processed foods relates to the quality of the dietary protein. Protein quality is generally assessed as a function of the ability of the constituent amino acids found within the food to meet the biological needs of the consumer. Different methods exist to determine the quality of dietary proteins, each with their own advantages and disadvantages. Because preparation methods also alter the product's protein quality, these factors must also be considered. This review will discuss recent advances in the determination of protein quality and the factors that influence the quality of pulse proteins for use in human foods.     

Subject Access for a Culinary Collection: Experiments at the Longone Center for American Culinary Research

ABSTRACT

A collection of culinary and related materials at the William L. Clements Library has potential uses beyond the niche of culinary history, expanding into and beyond the emerging interdiscipline of food studies. The library is considering other holdings for related content. Such collections are inadequately served by existing subject access. Experiments with plentiful subject access are being tried, including an unusual use of MARC records for ephemera, a database recording mentions of food-related phenomena in Civil War correspondence, and experimentation with a controlled vocabulary. These experiments have drawn on a “community of interest,” including subject specialists and volunteer docents.     

Hunting habitat selection by hen harriers on moorland: Implications for conservation management

We examine habitat use by hunting hen harriers Circus cyaneus at three study sites in Scotland to evaluate whether foraging patterns differ between sexes, sites, and stages of the breeding period. We modelled time spent hunting in focal plots as a function of habitat and nest proximity. Male hunting intensity (time spent hunting per hour of observation and km²) varied between sites and breeding periods, being lower during the nestling than the incubation period. Habitat use patterns were mostly consistent among study sites, which is important for developing species management recommendations applicable over the species’ range. Males avoided improved grassland, and selected areas of mixed heather and rough grass (with an optimum at ca. 50% heather cover). The effect of nest proximity was small. In contrast, females hunted mainly within 300-500 m of the nest, with a small additive effect of vegetation cover, areas of fragmented heather being preferred. Habitat management to benefit foraging harriers will involve creating (or maintaining) mosaics of heather/grassland around nest areas. Additionally, it might be possible to manipulate habitat to reduce conflict in areas where harrier predation on red grouse is important by segregating areas holding highest grouse densities (with high heather cover) from those favoured for harrier foraging (heather-grass mosaics). However, it would be necessary to test whether these manipulations might also influence harrier nest distribution, an effect which could negate any benefits from this strategy.     

人参果主要病毒检测方法研究

为了给人参果病毒检验及抗病性研究提供支持,对人参果采用ELISA和RT-PCR两种检测方法对8份田间材料中的马铃薯M病毒(PVM)、番茄花叶病毒(ToMV)和烟草花叶病毒(TMV)进行检测,对比筛选病毒检测方法。结果表明,ELISA法检测PVM的阳性检出率为87.5%;ToMV为37.5%,疑似率为12.5%;TMV为37.5%。通过RT-PCR检测体系,从人参果样品中分别扩增出与试验设计大小相符的特异条带,PVM阳性检出率为100%,ToMV为 50.0%,TMV为37.5%,检测灵敏性和准确性更高,检测结果符合率在87.5%以上。对扩增阳性产物进行凝胶回收测序,确定为目标条带。     

吉林西部生态农业基地土壤环境地球化学背景研究

吉林西部生态农业基地土壤样品地球化学指标分析结果表明,区内N和K元素与全球土壤背景值基本相当,P,Mg,S,Mn,Cu,Zn,Mo,Cd,Cr元素质量分数低于全球土壤平均值,土壤营养元素P、B、Zn、Mo缺乏,F、Se、As、Pb、Hg元素质量分数高于全球土壤平均值。近20年来,土壤背景中F质量分数下降0.41倍,P增加1.30倍。B、Zn、Mo有效量低于土壤临界值,为显著贫化。     

Farmer attitudes toward wolves: Implications for the role of predators in managing disease

The potential for disease transmission between wild and domestic animals may interfere with wildlife and habitat conservation on lands surrounding protected areas. Recently, possible transmission of bovine tuberculosis (Mycobacterium bovis) from wild ungulates to domestic livestock has affected the Riding Mountain National Park region in Manitoba, Canada. Wolf (Canis lupus) predation on ungulate populations may help lessen the risk of disease transmission to livestock. We conducted an exploratory analysis of causal factors associated with farmer attitudes toward observing wolves on their farms. A survey to 4 220 farms within 50 km of the Park resulted in an adjusted response rate of 25%. We constructed several logistic regression models with factors hypothesized to influence whether farmers agreed with the statement “I enjoy seeing wolves on my land”, and three candidate models received reasonable support. Factors most affecting attitudes were, in order of importance, perceived wolf population size, frequency of seeing wolves, perceived seriousness of wolf damage, distance to Park boundary and number of beef cattle (Bos taurus) owned. The factors least influential on attitudes were education and age. Concern over bovine tuberculosis in wild elk also had minimal influence. Of respondents who perceived the wolf population as “too high”, 60% were extremely concerned about bovine tuberculosis in wild elk. Although the role of wolf predation as a potential natural regulator of disease in wild ungulates might not be widely recognized in many areas, we believe this provides a unique opportunity to re-examine the significance of maintaining viable wolf populations.     

Energy or nutrient regulation of decomposition: Implications for the mineralization-immobilization response to perturbations

A model developed previously to describe the turnover of forest soil nitrogen is modified here to explain the effects of carbon and nitrogen additions on their dynamics. The model, which is structurally very simple, seems to explain correctly, among other phenomena, the negative correlation between N mineralization and CO₂ evolution observed in many experimental situations. An important variable used to explain this behaviour is the deficiency factor, which is related to the critical C-to-nutrient ratio and which gives a measure of the C or nutrient deficiency in the substrate with respect to the needs of the decomposers. Ways are discussed in which the model output can be used to explain the observed retention in the soil of fertilizer N added to mature forest soils.     

Knowledge and attitudes of children of the Rupununi: Implications for conservation in Guyana

Knowledge and attitudes of children towards wildlife and the environment were assessed through questionnaires given to 366 children in 9 schools in southwest Guyana. Children’s responses revealed that they had a general knowledge of wildlife but knew few details about specific species. Respondents thought that wildlife was important but were nonetheless tolerant of several forms of environmental exploitation. Visits by conservation organizations, Conservation International and Foster Parrots, were shown to increase appreciation of wildlife and the need to set up more protected areas, but unless programmes were concentrated and sustained they had little effect on attitudes towards environmental utilization and exploitation. Experience of the natural world in terms of owning a domestic animal or pet, having visited a zoo, or being a member of a wildlife club had little impact on children’s knowledge of wildlife and did not change attitudes to utilization and exploitation. Surprisingly, Guyanese children did not have particularly positive views about classic flagship species, such as jaguars, giant anteaters and tapirs, when compared to other species. Our findings suggest that zoos, wildlife clubs and conservation organizations could enhance the dissemination of their message through making more frequent and sustained visits, imparting more detailed knowledge, and exposing children to the potential dangers of utilization and exploitation; also that conservation organizations should reassess their use of standard flagship species in South America.     

Multi-scale effect of landscape processes and habitat quality on newt abundance: Implications for conservation

Recent studies in population dynamics suggest that landscape processes and habitat quality act at different scales on population abundances, but very few have modelled their simultaneous effects. However, at a time of large declines in natural populations, it is essential to understand such multivariate components. We tested the hypothesis that natural populations of palmate newts (Triturus helveticus) are affected on three scales: breeding patch (pond), habitat complementation (terrestrial cover), and metapopulation structure (density of ponds, surrounding populations). We conducted our survey in 130 ponds from southern France (Larzac) and analysed data with generalized additive models (GAM). Two main novel results emerge from these models: (1) the three landscape scales have significant effects on newt abundance, with more newts in deep, vegetated ponds, devoid of fish and surrounded by wooded areas and inhabited ponds; (2) the quality of the surrounding breeding patches is of primary importance in determining the abundance at core sites in a complex way: high abundances are associated positively with high densities of inhabited ponds, but negatively with the number of surrounding ponds. Deforestation, invasive species and abandonment of ponds all have negative impacts on the persistence of palmate newt populations. Future studies should encompass landscapes at different scales and incorporate the habitat quality in surrounding sites to better understand population dynamics and provide adequate conservation measures.