Michael Stocking

Handbook for the field assessment of land degradation.

Preface * Acknowledgements * List of Acronyms and Abbreviations * Gaining a Farmer-perspective on Land Degradation * What is Land Degradation? * What About the Land User? * Indicators of Soil Loss * Indicators of Production Constraints * Combining Indicators * Consequences of Land Degradation for Land Users * The Benefits of Conservation * Appendix I: Visual Indicators of Land Degradation * Appendix II: Forms for Field Measurements * Appendix III: Glossary - Terms Closely Related to Assessment of Land Degradation * Appendix IV: Annotated Bibliography * Appendix V: Major Tropical Soils and their Susceptibility to Land Degradation * Appendix VI: Investment Appraisal * Appendix VII: Suggested Outline for a Two Week Training Workshop in Land Degradation Field Assessment * Notes * Index

Knowledge in action: local knowledge as a development resource and barriers to its incorporation in natural resource research and development

Local knowledge (LK) cannot be assumed to be a necessary resource in development. The case must be argued successfully in the face of other development approaches which are indifferent or hostile to it. This paper identifies three distinct development approaches (or paradigms), the classic, neo-liberal, and neo-populist, which view the role of LK in the dynamics of technical change in different ways. Each approach often incorporates elements of various paradigms into strategy statements and policy or project documents. This paper focuses on the role of LK in natural resource (NR) research and development at the ‘development interface’. Here, stakeholders bring both local and scientific knowledge to the interface and, in relation to the dominant paradigm within which external actors operate, together produce an outcome termed ‘Knowledge-in-Action’ (KIA). Six ways in which KIA is produced are characterised, and it is recommended that priority be given to those likely to produce synergy. The paper also reviews the degree to which the ODA (UK) has so far integrated LK into natural resource development projects. The paper identifies a number of structural and behavioural barriers to a greater role for LK in natural resource research and development.

Agrodiversity: definition, description and design

Abstract ‘Agrodiversity’, a term of the 1990s, refers to interactions between agricultural management practices, farmers’ resource endowments, bio-physical resources, and species. If it is to have practical use, it must be codified as a basis for analysis. A division into overlapping and interrelated components is proposed, which distinguish spatial and temporal variations as well as related developmental issues such as livelihoods and food security.

Land rehabilitation by urban refuse amendments in a semi-arid environment: effect on soil chemical properties

Abstract The constituents of urban refuse may have potential chemical benifits in reclaiming degraded soils and improving plant growth, but this may be offset by chemical problems such as increased soil salinity and the accumulation of heavy metals. A series of experiments was conducted in the Fortuna Basin in semi-arid south-east Spain on a Xeric Torriorthent to investigate changes in soil properties with urban refuse amendments varying from 6.5 to 26 kg·m−2. Soil chemical properties were monitored during three years after the application of solid, largely organic, urban refuse. Changes in the contents of potassium, phosphorus, nitrogen, organic carbon, exchangeable sodium, electrical conductivity, and the sodium, chlorine and sulphates in the saturation extract, as well as a number of heavy metals are reported. Salts are quickly leached out, whereas essential plant nutrients are retained. There is a clear medium-term benefit to soil fertility with the use of urban refuse. Potential off-site impacts of diluted toxic contaminants are discussed

Soil erosion in developing countries:where geomorphology fears to tread!

Abstract Geomorphology claims an expertise in the study of soil erosion and the development of conservation solutions. Yet what are presented as “facts” about erosion, especially in developing countries where the need for conservation is greatest, is usually unhelpful and sometimes wrong. To understand why the scientific message becomes distorted, geomorphologists should see themselves as actors on a political economic stage, constrained in their role by ideological modes of analysis which themselves shift as science adopts particular ways of promoting itself. The answers given by geomorphological analysis are as much a product of ideology as they are of the process being studied. As applied scientists, geomorphologists could assist their cause greatly by providing quality information on erosion process rates and their impact in a timely and applicable way. Descriptive and predictive models hold scope for extending geomorphological information beyond empirical confines. Examples throughout the paper are drawn from projects in South Asia, South America and southern Africa.

Comparative evaluation of two models in predicting storm soil loss from erosion plots in semi-arid Spain

Abstract Soil loss models are commonly applied to obtain estimates of erosion for planning purposes. This paper asks whether it is safe to utilise two widely-used models, the Universal Soil Loss Equation (USLE) and the Soil Loss Estimation Model for Southern Africa (SLEMSA), to conditions for which they were not designed. Three mini-catchment erosion plots in semi-arid SE Spain are reported, which between them gave 24 measured storm soil loss events. Comparing this actual soil loss with what would be predicted by USLE and SLEMSA indicated that neither model can completely be applied with current knowledge of equation factor values. USLE gave approximately the right magnitude for prediction but with too low a spread in values and SLEMSA gave the better prediction of rank order of soil loss but greatly underestimated magnitude. It must be concluded that the blind application of empirical models to unmeasured situations will not give reliable predictions of soil loss.

A rapid method for assessing rates of soil erosion from rangeland: an example from Botswana.

Tbc erosion of rangeland soile is a widespread problem in Africa. Yet, there are few methods for estimating its rate. Using data fkom 2 catcbmenb in Botswana, a technique for esthuting erosion and sediment yield is demonstrated. It involvea low level pbotographk sampling of veget8tion cover, krighg to interpol8te percentage cover from sample points, and tbe application of a simplified soil IOM estimation procedure called SLEMSA. This modelling l pproocb gives gross soil loss and allows tbe estimation of sediment yield. It is easy and cheap to apply and gave results in line with field experience.

Soil degradation and its impact on desertification:A research design for Mediterranean environments

Summary Much is said but little is known of the processes and linkages of soil degradation with desertification. With particular emphasis on South-East Spain, a research design is proposed to characterize the processes, their dynamics and effect on productivity. Through detailed monitoring of plot experiments at three slope positions, changes in soil physical and chemical parameters and analyses of runoff and eroded sediments will be related to induced destruction of the vegetation. Knowing the cause and process will lead to the identification of management techniques that may protect vulnerable Mediterranean environments.

Farming and environmental degradation in Zambia: the human dimension

Abstract Farming and environmental degradation are inextricably linked through a complex of political, social, economic and physical forces. A connection is drawn between the initiation and maintenance of distinct farming systems (commercial, emergent and subsistence) by largely human influences, and the effect these farming systems have in turn on the environment. There are important implications for the environment through indirect effects on plant cover, cultivation methods and systems of bush fallowing. In many respects subsistence cultivation is probably the safest. A case study from Mkushi District, Central Province exemplifies the influence of external factors on environmental degradation in general, and soil erosion in particular. In the survey, traditional practices show fewer signs of soil erosion than commercial farming because of rational decisions taken by each group of farmers. The implication for conservation strategies is briefly reviewed.

Ecological and environmental indicators for the rapid appraisal of natural resources

Abstract Natural resource assessment is traditionally of a long-term nature. This paper examines some of the underlying assumptions and proxy measures involved in their rapid appraisal. Three case studies on soil colour, plant indicators and soil erosion illustrate a range of possibilities in using ecological and environmental indicators to appraise aspects of the physical environment which might normally be assessed by longer methods or not at all. It is concluded that the interdependence of environmental factors is high and hence suitable proxy measures can be found. Rapid—and thus low cost—monitoring of change is discussed. The importance of a clear statement of assumptions is stressed.