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Soil health

Soil health is a particularly pressing issue in the ACP region as tropical soils are prone to rapid degradation, but more specifically, because of declining soil fertility, salt intrusion and limited availability of arable land for agricultural production. ACP policy makers in consultation with soil and other scientists must provide measured responses to agricultural stakeholders who are faced with competing and contradictory recommendations on soil fertility management and emerging issues such as biochar for improved soil productivity and carbon trading schemes. This dossier addresses all of these issues in its collection of carefully selected publications and interesting web links. Two lead articles are also featured. In Soil Fertility in Africa by Dr. André Bationo, the complexity of and the shift in managing soil fertility, from the external input paradigm during the 1960s and 1970s to the currently accepted Integrated Soil Fertility Management (ISFM) paradigm is discussed. Dr. Bationo concludes that for investments in improving soil fertility to yield benefits - including adequate returns on investments- social, political and economic issues including output markets and the market value of farm products must be considered. Prof. Nazeer Ahmad’s article on Tropical soils with focus on West Indian soils provides an insight into Caribbean soils which are not as severely degraded when compared to other tropical regions, the exception being Haiti. Prof. Ahmad recommends that urgent attention should be paid to developing sustainable land use plans based on the capability of the Caribbean soils.

This folder on soil health has been edited by Judith Francis (CTA) and Jacqueline Sluijs (KIT). June 2009


Soil Fertility – Paradigm shift through collective action

by Dr. André Bationo, Director, AGRA West Africa & Senior Programme Officer, Soil Health Program (Research & Extension)
Countries in Sub-Saharan Africa (SSA) are among those with the highest rates of nutrient depletion (Stoorvogel and Smaling, 1990; Smaling, 1993; Smaling et al., 1997). A few highly influential studies of land degradation in Africa have provided substantial evidence. The International Centre for Soil Fertility and Agricultural Development (IFDC) estimated that Africa loses 8 million metric tons of soil nutrients per year and over 95 million ha of land have been degraded to the point of greatly reduced productivity (Henao and Baanante, 2006). At least 85% of African countries are estimated to have nutrient mining of above 30 kg of nutrients per ha per year and 40% of countries experience losses of over 60 kg of nutrients per ha per year (World Bank, 2006; Henao and Baanante, 2006). Equally the Global Assessment of Soil Degradation (GLASOD) reports that degraded soils amount to about 494 millions ha in Africa (Oldeman et al. 1991; Batjes 2001). It is also estimated that 65 per cent of SSA's agricultural land is degraded because of water and soil erosion, chemical and physical degradation (Oldeman et al. 1991; UNEP 1992; Scherr 1995). 25/09/2009
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TropSCORE - Tropical Soil Cover and Organic Resources Exchange Consortium

TropSCORE's goal is to encourage more sustainable tropical soil management throughout the cropping and fallow periods, with particular emphasis on practices involving soil cover and organic inputs, through increasing exchange of information and facilitating the synthesis of information by stakeholders in the North and South including farmers, extensionists, researchers, donors and policy makers. The website includes on-line extension material on cover crops, green manure, and fallows for small-scale farming in the tropics from a number of African and Central American countries. 17/07/2009
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Tropical soils with focus on West Indian Soils

by Prof. Nazeer Ahmad. Professor Emeritus of Soil Science, The University of the West Indies, St. Augustine, Trinidad & Tobago
Weathering or rock disintegration is rapid in the tropics due to high temperatures and leaching of the released nutrient elements caused by high rainfall. This leaves a highly resistant residue poor in plant nutrients, from which the soil develops. Tropical soils are infertile and considered fragile because the small amount of nutrients that is mostly concentrated on the soil surface can be easily lost. Since the farmers have little resources with which to maintain the soil fertility, they practise fallow but there are problems with this method as the fallow periods have become progressively shorter. In the Caribbean, although the land area is comparatively relatively small, the geology, rocks and soils are highly variable and almost every important grouping of soils is represented. Geologically the area is not very old so weathering, leaching and soil formation are not very advanced and the resulting soils are not as fragile and prone to rapid degradation as elsewhere in the tropics. As a whole, the soils are more resilient than in other tropical areas. 25/09/2009
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Technologies for Soil Improvement

This chapter on soil improvement in “Emerging Technologies to Benefit Farmers in Sub-Saharan Africa and South Asia” examines technologies to restore and maintain the physical structure of soils, improve the efficiency of water and nutrient use, and manipulate the rhizosphere to enhance the soil and plant performance. It presents some well-known methods for protecting and building soils that have not been widely adopted in SSA and SA but are essential for soil health, and some novel, science-based concepts for improving soil that require research and additional exploration.Download the chapter 17/07/2009
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