保护流域森林植被建立绿色防洪堤坝

根据 １９９８ 年我国洪灾的形成原因及特点, 分析森林植被的防洪作用, 包括防止水土流失、江河淤积、净化水源、改善水质、削减洪峰、调节水量等功能, 最后提出建立生态防洪堤坝的措施, 其中包括天然保护工程、森林植被恢复工程、坡地改造工程、小流域治理工程和绿色防洪堤坝建设的支撑体系。     

LEEP刀联合α-干扰素栓治疗宫颈糜烂疗效观察

目的探讨LEEP刀联合α-干扰素栓治疗宫颈糜烂的临床疗效及优越性。方法将96例宫颈糜烂患者分为观察组（54例）和对照组（42例）,对照组给予LEEP治疗,观察组给予LEEP联合α-干扰素治疗,观察两组患者治疗效果。结果观察组术后出血持续时间、创面愈合时间均明显早于对照组（P＜0.05）;观察组治疗总有效率为98.15%,明显高于对照组的80.95%（P＜0.05）。结论 LEEP联合α-干扰素栓治疗宫颈糜烂疗效好、恢复快,值得临床推广应用。     

中国水土流失的概况及其综合治理

本文以翔实的数据说明了我国水土流失严重的现状 ,并从良化生态环境 ,坚持综合整治、搞好小流域治理、提高防洪综合能力、加大执法力度、增强保水保土意识等方面 ,提出了防治我国水土流失的具体途径。     

坡耕地养分流失研究进展

文章重点论述了坡耕地养分流失的危害,以及降雨、坡度、土地利用方式和农作措施等因素对坡耕地养分流失的影响,并对坡耕地养分流失特征和主要防治措施进行了系统的归纳。     

Tourists’ representations of coastal managed realignment as a climate change adaptation strategy

In coastal destinations climate change adaptation is needed to address coastal erosion due to a combination of sea level rise and more frequent extreme weather events leading to loss of natural features and tourism infrastructure. Managed realignment is increasingly adopted as a strategy to address coastal change; however, this has often proved a contentious strategy with stakeholder groups. This study explores tourists' representational framework of managed realignment and how this frames understanding of the concept, understanding of how coastal resources might change and implications for future visitation. Data compiled using a questionnaire adopted a social representations theory perspective to analyse how collective tourists’ ideas may serve to mobilise the public in various ways. In general tourists have a poor understanding of managed realignment anchored to historic coastal management strategies and contextualised by use values with consequent implications for tourism planning and coastal management decision making.     

Economic benefit and ecological cost of enlarging tea cultivation in subtropical China: Characterizing the trade-off for policy implications

Cash crop expansion has become a global land use issue in recent decades. While the enlarging cash crop cultivation brings promising profitability, it can impair the delivery of various ecosystem services, with a risk of threat to sustainability and human well being. In order to make well-informed land use policy decisions, it requires elaborate efforts to characterize the trade-off between the benefit and cost of cash crop cultivation. This paper focuses on the enlarging tea cultivation in subtropical China, using a case of Anji County. We first monitor tea expansion from 1985 to 2016 based on time-series Landsat imageries, and then analyze the subsequent changes of water conservation service through an in-field survey of soil loss. Monetary approach is finally employed to evaluate the trade-off between economic benefit and ecological cost associated with the growing age of tea plantations. Results show that tea plantations expanded rapidly from 1985 to 2016 in Anji County. Delivery of water conservation service has been significantly impaired by the conversion from natural forests to tea plantations, but it can be gradually improved during the long rotational life cycles of tea plantations. For a given plot (1 ha at moderate slope), in theory, the economic benefit and ecological cost exhibit opposite trend associated the growing age of tea plantations, and an equilibrium point is approximately achieved at the 12-year growing age. In reality, ecological cost exceeds the economic benefit throughout the study period in Anji County. More specifically, the net difference increases from 11575 Yuan in 1985–1469167 Yuan in 2016. It denotes that economic benefit fails to compromise the ecological cost of the enlarging tea cultivation in Anji County. Conflicting land use policies (ecological conservation vs cash cropping promotion) and ‘household contract responsibility’ system should account for the unbalanced relationship between economic benefit and ecological conservation. We finally propose four major options towards the win–win possibilities between economic gain and ecological conservation associated with tea cultivation.     

Regional erosion risk mapping for decision support: A case study from West Africa

Effective soil and water management strategies require regional-scale assessment of erosion risk in order to locate prioritized area of intervention. Our study focuses on the Atacora mountain and surrounding areas (covering more than 18% of the total land area of Republic of Benin) which face a serious erosion threat despite their ecological and economic importance. To appraise the level of soil erosion risk of large area, we rely on the Instituto Nacional para la Conservación de la Naturaleza (ICONA) erosion model and use data from geographic information system (GIS). The erosion risk model requires four main inputs, namely, information on slope, lithofacies, land use and vegetation cover. The slope layer computed from ASTER digital elevation model (DEM) and the lithofacies layer inferred from digital pedogeological map are combined to draw soil erodibility map. To build soil protection map, we use land use/land cover layer extracted from LANDSAT 7 ETM + images in addition to vegetation cover layer derived from MODIS NDVI product. The final erosion risk map (with a resolution of 1 arc second) is obtained by overlapping erodibility and soil protection maps. We find that 21.8%, 58.5%, and 19.5% of the study area presents very low to low, medium, and high to very high level of erosion risk, respectively. Moreover, our findings are aggregated at the district-level (administrative unit). We observe that erosion risk is more acute in Boukoumbe district. Kerou, Kobli and Natitingou districts are mildly affected by erosion risk, while Kouande, Materi, Pehunco, Tanguieta and Toucountouna districts face a low risk. Ultimately, the proposed erosion risk map can help researchers and decision makers design and implement effective soil and water management interventions in the study area.     

Understanding the influence of farmer motivations on changes to soil erosion risk on sites of former serious erosion in the South Downs National Park,UK

Serious soil erosion occurred in the South Downs National Park, southern England in the years 1982–2006 and details of around 400 sites are contained in a database. In 2010 we revisited 85 of the most serious sites where erosion of >10 m³ ha⁻¹ y⁻¹ had been recorded in order to assess land use change and any conservation measures undertaken. At 79% of the sites land use change had resulted in a reduction in the risk of erosion, most notably at 28 sites with a shift to permanent grass from winter cereals. At only 21% of sites was the risk of erosion unchanged. Twenty two farmers responsible for 66 of the sites were interviewed. Land management practices had changed on all of the fields of interest to this study since the time of the serious erosion events, to those which have the potential to lower soil erosion risk. Sixteen interviewees claimed that erosion was a motivating reason for changing their practices, due to either experiencing on or on- and off-farm impacts firsthand (12), having knowledge or suspicion of serious erosion having occurred on their land prior to their management (three), or having no knowledge of any serious erosion on their land but just wanting to reduce overall erosion risk (one). Amongst the main changes reported are changes of land use from winter cereals to grass or to overwinter stubble which have undoubtedly reduced the risk of erosion. However, some changed practices claimed by farmers, such as along-the-contour-working, earlier sowing and the use of rollers may be of little value. Furthermore, deeper analysis of farmers’ motivations regarding changes in land management practices suggests a complex picture in which a range of socio-economic influences come into play over time including financial incentives offered by agri-environmental schemes which were found to be an important driver of change. Future changes in farming economics may therefore undermine the reduction in erosion risk in the longer term.     

Changes in Brazil’s Forest Code can erode the potential of riparian buffers to supply watershed services

In Brazil, the Forest Code requires landholders to maintain fixed-width buffers of native vegetation along watercourses – legally called Areas of Permanent Preservation (APPs). In 2012, agricultural activities started to be partially allowed in APPs, but only if best management practices on soil and water conservation are adopted and if a narrow buffer strip with native vegetation is restored adjacently to the watercourse. In this paper, we present a modeling framework to investigate the capacity of legal compliant APPs to supply watershed services (erosion control and stream bank stabilization) in a 2,200 ha watershed in São Paulo State, Brazil. Our results suggest that the narrower the riparian buffer the lower the control of soil erosion dynamic within APPs, and that riparian buffers smaller than 8 m can act as a source of sediments to streams. The adoption of best management practices can contribute to controlling soil erosion within APPs but the presence of native forests in the first 15 m is necessary to guarantee equivalent protection to streams when compared to APPs completely covered by forests. Moreover, we observed that forest restoration within APPs helped to reduce the average soil loss of the watershed by only 20 %, compared to a reduction of 55 % when best practices are implemented in all watershed agricultural areas. We conclude that (i) the reduced requirements for APP restoration may contribute to stream sedimentation, which will likely affect the supply of watershed services by stream ecosystems; (ii) the implementation of best management practices in APPs will not have the same effect as native forests to reduce stream sedimentation; and (iii) the adoption of best management practices in all agricultural production areas – and not only within APPs as required by law – is the best strategy to promote the supply of watershed services to society.     

Book review

Smallholder farmers who grow diverse landraces in centres of crop diversity contribute to sustaining the capacity of agricultural and food systems to adapt to change by maintaining crop evolution in their fields today, thus enabling humanity to continue to have the broad genetic variation needed to adapt crops to changes tomorrow. Given this fact, the last 20 years have witnessed an ever-growing interest in on-farm conservation of crop infra-specific diversity. While numerous projects to support it have been, and continue to be, implemented worldwide, there has been very little systematic assessment of the extent to which these projects have been effective at contributing to the maintenance of crop diversity on-farm and the creation of associated benefits for the farmers involved. The factors and relationships implicated in attaining conservation and livelihood results are complex, so that a conceptual scheme that brings them together in a simplified but coherent fashion can be extremely useful for the scientists, donors, policy-makers and practitioners concerned. This paper presents a conceptual framework for analysing on-farm projects, the trade-offs involved and assesses their success in a more systematic way.