The role of social learning for soil conservation: the case of Amba Zuria land management,Ethiopia

Social learning plays key roles in sustainable natural resource management; however, studies on its role show mixed results. Even though most current studies highlight positive outcomes, there are also negative effects of social learning with respect to natural resource management. This paper explores the influence of social learning outcomes on the adoption of soil conservation practices in Amba Zuria, Ethiopia. Data were collected through semi-structured interviews, group discussions and in workshops. The interviews were transcribed and analysed with the qualitative data analysis software ATLAS.ti. In addition, a review of pertinent documents and literature complements the analysis. We found that social learning results in positive outcomes in interactions among the actors, broader understanding on soil conservation, trust and mutual understanding, and the creation of opportunities to apply both indigenous and scientific knowledge. These outcomes, in turn, foster the adoption of stone terraces to conserve soils. No such positive results were found for farmers who were not involved in the learning process and who did not adopt stone terraces. The non-adoption can partly be explained by their exclusion from sharing the positive outcomes of social learning. The study also shows limitations related to the short duration of the learning platforms, insufficient representation of women and irregular patterns of learning schedules. Hence, Ethiopian soil conservation strategies should put emphasis on social learning in order to strengthen the collective processes of soil conservation measures.     

Exploring co-investments in sustainable land management in the Central Rift Valley of Ethiopia

In Ethiopia, not only farmers but also the public and private sector partners are still hesitant to invest in sustainable land management (SLM). This study focuses on the Central Rift Valley and explores the potential for co-investments in SLM, where public and private sector partners support farmers with material, capital, knowledge, etc. A survey revealed current bottlenecks for co-investments and requirements needed to collaboratively invest in SLM. It covered 165 public sector partners (micro-, meso- and macro-level institutions) and 42 private sector partners (banks, exporters and local traders). Results for the public sector show a gap between macro- and micro-/meso-level actors concerning co-investments in SLM. Macro-level institutions do not acknowledge the bottlenecks identified by micro- and meso-level institutions (e.g. lack of accountability, top-down approaches and lack of good leadership). Similarly, opinions on requirements for co-investments in SLM differ considerably, showing that bridging the institutional micro–macro gap is crucial to co-investments. Most factors are related to the wider governance context and to different perceptions among micro- and macro-level actors as to the critical pre-conditions to co-investment in SLM. Improving governance at all institutional levels, capacity building and enhancing a common understanding on barriers to SLM is required. Results for the private sector reveal that economic bottlenecks limit possibilities to co-invest in SLM, and that enabling policies in the public sphere are required to trigger private investments. Hence, the potential for co-investments in SLM is available in Ethiopia at micro- and meso-level and within the private sector, but profound commitment and fundamental policy changes at the macro-level are required to exploit this potential.     

黄土高原小流域水土保持决策系统研究

以陕西省米脂县泉家沟流域为例,在黄土高原小流域水土保持实用技术的基础上,应用USLE修正式对梁峁边线以上梁峁坡地进行了水土保持技术决策;并在PCARCINFO系统支持下,设计了决策系统。     

Methodological integration for sustainable natural resource management beyond field/farm level: lessons from the ecoregional initiative for the humid and sub-humid tropics of Asia

SUMMARY

Integrated natural resources management (INRM) has to address both the livelihood goals of farmers and the ecological sustainability of agroecosystems and natural resources. Under the Ecoregional Initiative for the Humid and Sub-Humid Tropics of Asia — Ecor(1)Asia — one major set of activities has been the development of approaches, methodologies, and tools to meet the challenges of INRM research for sustainable agricultural development. Examples provided illustrate the role of these methodologies in the three main phases of knowledge development for improving INRM impact: knowledge generation, knowledge capitalization, and knowledge mobilization. The methodologies are designed for better integration across disciplines, spatial scales, and hierarchical levels of social organization. Attempts are made to quantify trade-offs between biophysical sustainability and socio-economic considerations. The case is made for using these methodologies in a more complementary manner to help bridge the topdown and bottom-up approaches in INRM. Inherent in the developing and implementing of these methodologies is the forging of partnerships and fostering linkages with multiple stakeholders, as well as using the knowledge base and integrative tools as communication platforms.     

丘陵红壤开发的水土资源保护及农业产业化经营模式

以湖南省桃源县为例,针对目前丘陵红壤开发存在的主要问题,在探明季节性干旱成因和发生规律、水资源合理调蓄利用依据的基础上,提出了红壤丘陵区抗御季节性干旱的水分管理对策和主要措施;通过不同经营模式的水土资源动态观测、分析,提出了红壤丘陵区土壤允许流失值应≤200 t·km-2·a-1、相应的降水径流系数<0.25 等水土资源协调发展的关键技术指标,并在丘陵红壤坡地上建立了土壤侵蚀模数<100 t·km-2·a-1 的“土壤-水分-生物”资源互利型的高效利用模式。同时,以市场为导向,优化产业结构为中心,应用上述研究成果,建立了茶叶、苎麻、果业、庭园高效生态农业等四大科技先导型的产业化规模经营体系,为我国红壤丘陵区的农业产业化开发提供实用模式与示范样板。     

Monitoring land use/land cover change impacts on soils in data scarce environments: a case of south-central Ethiopia

To monitor land-use/land-cover (LULC) change and assess its impact on the soil property, the availability of benchmark data is indispensable, which is hardly available in the intensively cultivated regions of developing countries. Our study attempts to solve this problem by generating a benchmark soil data through the development of modified spatial analogue (MSA) method in the context of the Upper Dijo River catchment, south-central Ethiopia. The magnitude and patterns of LULC changes were extracted from air photos and satellite imageries, along with the acquisition of soil samples from the reference and target sites through ground survey. Analysis of digital image processing shows significant LULC changes in a period that spanned three decades. The impact of LULC change on soil quality was assessed by comparing the soil physico-chemical properties sampled from the reference and target sites. The result shows a decline in total nitrogen, organic matter, available potassium and pH levels in soils collected from target sites, which conforms to results reported by studies conducted in data-rich environment. With careful validation, MSA could be useful for monitoring soil property changes in data-scarce environment and generate soil-related parameters for agro-ecological models.     

Positives and pathologies of natural resource management on private land‐conservation areas

In managed natural resource systems, such as fisheries and rangelands, there is a recognized trade‐off between managing for short‐term benefits and managing for longer term resilience. Management actions that stabilize ecological attributes or processes can improve productivity in the supply of ecosystem goods and services in the short term but erode system resilience at longer time scales. For example, fire suppression in rangelands can increase grass biomass initially but ultimately result in an undesirable, shrub‐dominated system. Analyses of this phenomenon have focused largely on how management actions influence slow‐changing biophysical system attributes (such as vegetation composition). Data on the frequency of management actions that reduce natural ecological variation on 66 private land‐conservation areas (PLCAs) in South Africa were used to investigate how management actions are influenced by manager decision‐making approaches, a largely ignored part of the problem. The pathology of natural resource management was evident on some PLCAs: increased focus on revenue‐generation in decision making resulted in an increased frequency of actions to stabilize short‐term variation in large mammal populations, which led to increased revenues from ecotourism or hunting. On many PLCAs, these management actions corresponded with a reduced focus on ecological monitoring and an increase in overstocking of game (i.e., ungulate species) and stocking of extralimitals (i.e., game species outside their historical range). Positives in natural resource management also existed. Some managers monitored slower changing ecological attributes, which resulted in less‐intensive management, fewer extralimital species, and lower stocking rates. Our unique, empirical investigation of monitoring‐management relationships illustrates that management decisions informed by revenue monitoring versus ecological monitoring can have opposing consequences for natural resource productivity and sustainability. Promoting management actions that maintain resilience in natural resource systems therefore requires cognizance of why managers act the way they do and how these actions can gradually shift managers toward unsustainable strategies.     

Integrating local knowledge with science and technology in management of soil,water and nutrients: implications for management of natural capital for sustainable rural livelihoods

Harnessing local knowledge and practices for sustainable management of soil, water and nutrients is important for sustainable development. This work aims to understand soil productivity in traditional open-ridging practices and integrate scientific ideas and technologies into traditional practices for enhancing management of soil productivity. Participatory assessments, household surveys, field experiments, observations and analyses of outcomes were used. Participatory assessments revealed declining natural soil fertility and maize productivity over time, a concern reiterated by 82.5% of respondents. Evaluation of ridge tillage practices showed that bean yields were significantly (p?<?0.05) higher by 19–35% in traditional open ridges and increased by 23–38% when ties were integrated. Integration of fertilizers resulted in significantly (p?<?0.05) higher subsequent maize yields in tied ridges than in traditional open ridge and flat cultivation practices. Improved integrated tillage practices resulted in increased soil and water conservation, soil fertility and crop tolerance to prolonged no-rainfall spells. National development policies should create enabling environments for smallholder farmers to integrate modern knowledge and technologies with their traditional knowledge and practices in land management for high and sustained quality of natural capital for secure and sustainable livelihoods.     

Determination of the levels of selected metals in seeds,flowers and fruits of medicinal plants used for tapeworm treatment in Ethiopia

The level of accumulation of selected essential and non-essential metals, namely; Ca, Cu, Fe, Zn, Mn, Cd, Pb, and Cr have been investigated in the seeds, fruits, and flowers of some medicinal plants utilized for tapeworm treatment in Ethiopia and their respective soil samples. These include seed of Cucurbita maxima (Duba), fruit of Embelia abyssinica (Ankoko), flowers of Hagenia abyssinica (Kosso), and fruits of Rosa abyssinica (Kega) and their respective soil samples. A wet digestion procedure with a mixture of conc. HNO₃ and HClO₄ for the plant samples and a mixture of conc. HNO₃, HCl, and H₂O₂ for soil samples were used to solubilize the metals. Ca (1280–12,670?mg?kg^?1) was the predominant metal followed by Fe (104–420?mg?kg^?1), and Zn (18–185?mg?kg^?1) in all the plant materials except for Hagenia abyssinica flower from Hirna in which Mn (16–42?mg?kg^?1) followed by Fe. Among the non-essential toxic metals, Pb was not detected in Cucurbita maxima of Boji, Gedo and Hirna origins and in Rosa abyssinica of Hirna site. Similarly, Cr was not detected in Rosa abyssinica fruits of Boji and Gedo sites. The sampled soils were found to be between strongly acidic to weakly basic (pH: 4.7–7.1). In the soil samples, Ca (8528–18,900?mg?kg^?1) was the most abundant metal followed by Fe (417–912?mg?kg^?1), Zn (155–588?mg?kg^?1), Mn (54–220?mg?kg^?1), Cr (21–105. mg?kg^?1), Cu (11–58?mg?kg^?1), Pb (13–32?mg?kg^?1) and Cd (2.8–4.8?mg?kg^?1). The levels of most of the metals determined in the medicinal plants and the respective soil samples are in good agreement with those reported in the literature and the standards set for the soil by various legislative authorities.     

Fishery resource management in Chilika lagoon: a study on coastal conservation in the Eastern Coast of India

A significant proportion of the fishing population comprises small-scale fishermen and many studies illustrate that these people are exploited by middlemen in the process of fish marketing combined with money lending. The negative dependency gives rise to poverty and triggers indiscriminate fish catch that threatens fishery resources depletion. This article explores the root causes of failures in resource-led development from the viewpoint of coastal resource conservation. The study presents a case study of Chilika lagoon, India and focuses on the interaction between small-scale fishermen and middlemen. The findings reveal that most of the small-scale fishermen have been exploited by specific middlemen and the underlying causes of the present fish marketing structure stem from (i) indebtedness and (ii) the unstable situation because of perpetual conflicts over fishery resources among the fishers across Chilika lagoon. Based on these observations, this article presents some recommendations on fishery resource conservation from the perspective of a fish marketing structure.

云南元谋干热河谷区土壤侵蚀对土壤肥力的影响

探讨了云南元谋干热河谷区土壤侵蚀对土壤肥力性质的影响．研究表明，土壤侵蚀使土壤中全氮、全磷、全钾以及碱解氮、速效磷、速效钾等养分淋失；同时，有机质含量减少，土壤有机无机复合量降低，松结态腐殖质减少．Ａ／Ｃ值下降；土壤中的过氧化氢酶、蔗糖酶、脲酶等活性也因侵蚀而降低．土壤侵蚀越强烈，土壤肥力退化愈严重．     

洞庭湖区的湖垸农业与可持续发展对策

在调查分析洞庭湖区围湖垦殖和湖垸农业形成的历史的基础上，归纳了湖垸农业面临的生态环境问题：洪涝灾害发生频率加大；水面减少，生物多样性降低；环境污染严重，湿地生态功能衰退；土壤退化和潜育化严重；血吸虫病死灰复燃。并结合已有的经验，提出了湖垸农业可持续发展的对策措施：认真实施生态保护工程，减少泥沙淤积；调整湖垸农业结构，建立有利于避灾、减灾新模式；退田还湖，发展替代农业，发展莲藕、籽藕、茭白等水生经济植物种植；与企业结合，发展油菜、马铃薯、亚麻等工业原料作物；利用欧美杨耐涝性强的特点，在地势较高的季节性淹没的洲滩地，发展以林为主的林农复合经营模式，湖洲草地发展草食畜禽替代模式。     

川中丘陵区紫色土坡耕地土壤侵蚀特征

利用137Cs示踪方法与耕作侵蚀模型评价了川中丘陵区紫色土坡耕地土壤侵蚀速率,并通过比较分析方法探讨了2种典型坡耕地-短陡坡与缓长坡耕地-土壤侵蚀特征差异。结果表明,短陡坡耕地土壤侵蚀速率高达52.6 t.hm-2.a-1,是缓长坡耕地土壤侵蚀速率（26.7 t.hm-2.a-1）的2倍。耕作侵蚀是短陡坡耕地的主要侵蚀过程,它整体性搬运土壤,其对土壤总侵蚀的贡献高达74%。水蚀是缓长坡耕地的主要侵蚀过程,其分选性搬运土壤,对土壤总侵蚀的贡献为55%。短陡坡耕地与缓长坡耕地土壤侵蚀速率均沿着向下坡方向逐渐降低,但短陡坡耕地土壤侵蚀速率下降梯度明显高于缓长坡耕地。耕作侵蚀导致两种坡耕地的坡顶土壤损失最为严重。因此,川中丘陵区的耕作侵蚀风险应该引起重视。     

耕作措施对三峡库区土壤侵蚀和养分流失的影响

为研究三峡库区土地耕作措施对土壤侵蚀和营养物质流失的影响,在三峡库区张家冲小流域设置10个不同土地利用方式的试验小区,在自然降雨条件下,进行为期1 a的小区试验,研究不同土地利用方式下土壤侵蚀和径流中氮、磷流失特征.结果表明:在10个试验小区中,土坎梯种柑小区年均径流量和土壤侵蚀量最大,土坎篱种柑小区年均径流量最小,坡地种粮小区土壤侵蚀量最小;坡篱种粮小区总氮和总磷年流失量最大,坡地种柑小区年流失量最小;土壤侵蚀和营养物质流失主要发生在6-8月降雨集中的暴雨季节.在类似于研究区域的其他农业区域,适合于坡地种柑,而坡篱种粮和土坎梯种柑是不适合推广的种植方式.     

关中东部缓坡地面全新世土壤侵蚀与沉积发展演变规律研究

对华县古洪积扇全新世黄土一土壤剖面的磁化率、粒度进行分析研究，揭示了全新世以来缓坡地面面状流水侵蚀和沉积的发生规律。研究结果表明，晚更新世末期，由于黄土土质疏松，植被薄弱，在即将进入全新世时有自然侵蚀沉积发生；在全新世4000aB．P.之前，洪积扇特殊的环境生态条件造成土壤堆积时期土壤水分缺乏，成壤较弱，面状流水侵蚀与沉积活动不明显。自夏商时代以来，农业耕垦活动影响古洪积扇地表，促进了坡面流水侵蚀堆积过程，发生了面状流水侵蚀；从3100aB．P.开始气候干旱，人类活动强烈地影响着当地的生态环境，加速了面状流水侵蚀沉积；隋唐以来人类活动引起的加速侵蚀沉积则更进一步增强，这个过程反映土壤侵蚀呈现阶段性加速的趋势。由此可见，土壤侵蚀的加速是与人类的活动相伴随，随着人类活动强度的增强，土壤侵蚀在自然侵蚀的基础上，呈现加速趋势。     

三峡库区生态系统服务功能重要性评价及其空间分布研究

以长江上游重点生态脆弱区三峡库区(重庆段)为研究区,结合RS和GIS软件,选取生物多样性维护功能、水源涵养功能和水土保持功能为评价指标,采用植被净初级生产力(vegetation net primary productivity,NPP)定量指标评估法,综合分析研究区2020年生态系统服务功能的重要性程度以及空间分异特...     

The impacts of Robinia pseudoacacia litter cover and roots on soil erosion in the Loess Plateau,China

The impacts of vegetation on soil erosion are closely associated with the combined effects of above- and below-ground components. In this study, we explore the effects and contributions of Robinia pseudoacacia litter cover and roots on soil erosion. Experiment sites under natural conditions with vegetation cover, plant roots and bare ground plots were investigated for overland flow discharges of 0.5, 1.0 and 2.0?L?s^?1 and slope gradients of 8.7%, 17.6%, 26.8%, 36.4% and 46.6%. Results indicate that litter cover and roots have a significant impact on sediment reduction; soil loss was reduced by about 57% and plant roots had a greater impact on the reduction of soil erosion than litter cover. The combination of litter cover and plant roots had a significant effect on decreasing K_r, increasing τ_c and consequently strengthening soil resistance capacity to erosion. When plants and roots existed on the slopes, K_r decreased by 81% and 66%, and τ_c increased by 319% and 246%, respectively, in comparison with bare slopes. These results illustrate the importance of high-forest in controlling soil erosion by quantifying the specific contributions of litter cover and plant roots in erosion reduction in the Loess Plateau.     

Bayesian predictive inference for the proportion of eroded land in a small area in Iowa

There is an increasing interest in the quality of soil, especially for small geographical areas. We present a method to estimate the percent of the area in a county or hydrological basin that is eroded. There are sample data (for several counties in eastern Iowa) from the National Resources Inventory and population data on land use, land capability class, rainfall and slope length and steepness. Using the Gibbs sampler we perform Bayesian predictive inference to obtain estimates for the non-sampled units. These estimates, together with the sample data, provide an estimate of the proportion of the total area that is eroded. We assess the quality of fit of our model using two cross-validation exercises and graphical methods.     

基于RUSLE模型的三峡库区腹地土壤侵蚀演变研究

基于RS、GIS技术与RUSLE土壤流失模型相结合的方法分析研究巫山—奉节地区土壤侵蚀时空演变规律,为巫奉两县水土保持措施提供参考依据.研究表明:1)1988—2015年间,研究区土壤侵蚀模数呈现先增后减的变化趋势,2000年侵蚀最为严重,平均侵蚀模数达到4030.99 t/(km2·a).2)三峡库区建设初期和中期土...     

Assessment of land degradation and its impact on crop production in the Dry Zone of Myanmar

Land degradation in terms of soil degradation is a major environmental issue posing threat to sustainable livelihood in the semi-arid region of Central Myanmar. However, the studies on soil degradation status and its impacts in this region are very scanty. The objective of this study was to determine the impact of land degradation on crop production both in terms of area and yield in the Dry Zone of Myanmar. Remote sensing and geographic information system-based modelling was utilized to assess and map soil erosion rates. Household survey was conducted to understand the causes of land degradation and its impacts on crop productivity and livelihoods. It has been found out that the current rate of soil erosion ranged from 0 to 114 t ha^–1 yr^–1, and that the average rate of soil erosion increased from 14.2 to 54.6 t ha^–1 yr^–1 over a period from 2000 to 2012. The major types of land degradation were physical and chemical soil degradation. Farmers identified topographic condition, soil types, improper crop management practices and climatic factors as the main causes of soil erosion. The observed crop yields of monsoon rice, groundnut, sesame and cotton in the highly degraded area were 3–12 times lower compared with the yields of these crops grown in less degraded area. Livelihoods of the farmers in the high-degraded area were affected by crop yield reduction, increased cultivation cost and increased uncultivable land area. The impact of land degradation on crop production was dependent on the severity of degradation. This suggests that advanced conservation measures are immediately required and the supportive policy strategies need to be implemented to educate farmers and to strengthen extension services for sustainable land management in the Dry Zone of Myanmar.