Determination of yield and erosion damage functions using subjectively elicited data: application to small holder tea in Sri Lanka

Tea has been Sri Lanka's major export earner for several decades. However, soil erosion on tea-producing land has had considerable on-site and off-site effects. This study quantifies soil erosion impacts for smallholder tea farms in Sri Lanka by estimating a yield damage function and an erosion damage function using a subjective elicitation technique. The Mitscherlich-Spillman type of function was found to yield acceptable results. The study indicates that high rates of soil erosion require earlier adoption of soil conservation measures than do low rates of erosion. Sensitivity analysis shows the optimum year to change to a conservation practice is very sensitive to the discount rate but less sensitive to the cost of production and price of tea.

Estimating the user cost of soil erosion in tea smallholdings in Sri Lanka

Soil erosion in developing countries is a widespread problem causing considerable economic damage. It still remains an intractable problem in many countries. Available research findings on costs of soil erosion indicate them to be high. Soil erosion continues to be a problem due to the difficulties of estimating the economic damages and attendant difficulties in developing effective control policies. This paper considers soil to be a nonrenewable resource and estimates the marginal user costs using a yield damage function. Results indicate user costs to be low for individual farms. The low user costs are due to some of the assumptions made with respect to a number of parameters such as prices of tea, costs, and technological developments. The results also indicate that marginal user costs are sensitive to prices, soil depth and soil loss.

Soil erosion in developing countries: a socio-economic appraisal

Soil erosion is the single most important environmental degradation problem in the developing world. Despite the plethora of literature that exists on the incidence, causes and impacts of soil erosion, a concrete understanding of this complex problem is lacking. This paper examines the soil erosion problem in developing countries in order to understand the complex inter-relationships between population pressure, poverty and environmental-institutional dynamics. Two recent theoretical developments, namely Boserup's theory on population pressure, poverty and soil erosion and Lopez's theory on environmental and institutional dynamics have been reviewed. The analysis reveals that negative impacts of technical change, inappropriate government policies and poor institutions are largely responsible for the continued soil erosion in developing countries. On the other hand, potential for market-based approaches to mitigate the problem is also low due to the negative externalities involved. A deeper appreciation of institutional and environmental dynamics and policy reforms to strengthen weak institutions may help mitigate the problem.

Effect of increased temperature on erosion-corrosion under turbulent conditions in Bayer liquor

A study of the behaviour of mild steel in synthetic Bayer liquor at 25 °C and 95 °C showed that turbulent conditions had a small effect on the anodic currents at 25 °C, but caused large increases in currents at 95 °C. This may be due to the increased solubility of magnetite at the higher temperature.

Adaptation planning for coastal inundation and erosion at the local level : a knowledge systems perspective

Scientific projections for climate change induced sea level rise highlight the potential for serious consequences in low lying coastal areas, through impacts upon: built infrastructure; beneficial uses; and ecological values. An area of particular concern relates to the ways in which issues associated with land may be subject to future inundation and, or, erosion. Responding to such issues is complex and challenging, requiring consideration of multiple sources of evidence (with varying levels of certainty), diverse organisational settings and priorities, and multiple perspectives on what the evidence means. Further, limited attention has been directed towards exploring the knowledge dynamics associated with coastal adaption planning. In this paper we explore the knowledge dynamics associated with coastal adaption planning, in order to highlight the inter-organisational and inter-personal challenges involved. We do so by drawing on the views expressed in semi structured interviews by stakeholders with an interest in coastal climate change. The particular focus is on exploring how different actors perceive coastal adaption planning process, and the tensions, challenges, and implications associated with, and arising from, the way in which coastal adaptation knowledge is exchanged.

Measurement error causes scale-dependent threshold erosion of biological signals in animal movement data

Recent advances in telemetry technology have created a wealth of tracking data available for many animal species moving over spatial scales from tens of meters to tens of thousands of kilometers. Increasingly, such data sets are being used for quantitative movement analyses aimed at extracting fundamental biological signals such as optimal searching behavior and scale-dependent foraging decisions. We show here that the location error inherent in various tracking technologies reduces the ability to detect patterns of behavior within movements. Our analyses endeavored to set out a series of initial ground rules for ecologists to help ensure that sampling noise is not misinterpreted as a real biological signal. We simulated animal movement tracks using specialized random walks known as Lévy flights at three spatial scales of investigation: 100-km, 10-km, and 1-km maximum daily step lengths. The locations generated in the simulations were then blurred using known error distributions associated with commonly applied tracking methods: the Global Positioning System (GPS), Argos polar-orbiting satellites, and light-level geolocation. Deviations from the idealized Lévy flight pattern were assessed for each track after incrementing levels of location error were applied at each spatial scale, with additional assessments of the effect of error on scale-dependent movement patterns measured using fractal mean dimension and first-passage time (FPT) analyses. The accuracy of parameter estimation (Lévy μ, fractal mean D, and variance in FPT) declined precipitously at threshold errors relative to each spatial scale. At 100-km maximum daily step lengths, error standard deviations of ≥10 km seriously eroded the biological patterns evident in the simulated tracks, with analogous thresholds at the 10-km and 1-km scales (error SD ≥ 1.3 km and 0.07 km, respectively). Temporal subsampling of the simulated tracks maintained some elements of the biological signals depending on error level and spatial scale. Failure to account for large errors relative to the scale of movement can produce substantial biases in the interpretation of movement patterns. This study provides researchers with a framework for understanding the limitations of their data and identifies how temporal subsampling can help to reduce the influence of spatial error on their conclusions.

Guarding against the erosion of competitive advantage: a knowledge leakage mitigation model

A critical objective of knowledge-intensive organizations is to prevent erosion of their competitive knowledge base through leakage. Our review of the literature highlights the need for a more refined conceptualization of perceived leakage risk. We propose a Knowledge Leakage Mitigation (KLM) model to explain the incongruity between perceived high-risk of leakage and lack of protective actions. We argue that an organization's perceived risk of leakage increases if competitors can benefit from leakage incidents. Further, perceived leakage risk decreases if the organization is shielded from impact due to their diversity of knowledge assets and their ability to reconfigure knowledge resources to refresh their competitive knowledge base. We describe our approach to the design of a large-scale survey instrument that has been tested and refined in two stakeholder communities: 1) knowledge managers responsible for organizational strategy, and 2) Information security management consultants.