AGL/MISC/23/99 INTEGRATED SOIL MANAGEMENT FOR SUSTAINABLE AGRICULTURE AND FOOD SECURITY IN SOUTHERN AND EAST AFRICA

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1 AGL/MISC/23/99 INTEGRATED SOIL MANAGEMENT FOR SUSTAINABLE AGRICULTURE AND FOOD SECURITY IN SOUTHERN AND EAST AFRICA

2 AGL/MISC/23/99 INTEGRATED SOIL MANAGEMENT FOR SUSTAINABLE AGRICULTURE AND FOOD SECURITY IN SOUTHERN AND EAST AFRICA PROCEEDINGS OF THE EXPERT CONSULTATION Harare, Zimbabwe 8-12 December 1997 H. Nabhan A. M. Mashali A. R. Mermut FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS Rome, 1999

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4 Preface Land degradation, either natural or induced by humans, is a continuing process. It has become, however, an important issue through its adverse effects on national natural resources, food security, and the livelihood of the world population. Much has been said and documented about land degradation but there are still gaps of knowledge, due to the fact that only a few countries have really developed cost-effective technologies for mitigation. Inappropriate land use is a major cause of declining soil quality. In many countries, especially in sub Saharan Africa, there is continuous stress on the limited land resources due to population pressure. Food security is directly related to the ability of land to support the population. Causes for land degradation are numerous and include decline of soil fertility, development of acidity, salinization, alkalization, deterioration of soil structure, accelerated wind and water erosion, loss of organic matter and biodiversity. Efforts to restore productivity of a degraded land must be coupled with efforts to recognize productive capacity of soil resources. Restoring the soil quality for crop production through the appropriate soil management and conservation techniques is important for all nations, primarily those at risk with respect to food security. Although cost effective options are available to restore the soil quality and productivity, there is a need to increase awareness at high policy-making level with sound scientific evidence. It is, therefore, important to develop spatial or other databases about the extent of soil degradation, its biophysical, economic and social impacts, as well as successful examples of soil productivity improvement programmes. The FAO Land and Water Development Division (AGL), in collaboration with the Subregional Office for Southern and East Africa (SAFR) and the Agricultural Technical and Extension Services (AGRITEX) of Zimbabwe, organized this expert Consultation on "Integrated Soil Management for Sustainable Agriculture and Food Security" with the following main objectives: examine the status of land degradation under contrasting agro-ecological conditions; exchange experiences on constraints for controlling land degradation and examine possible solutions to overcome these constraints; discuss proposals for national and subregional programmes in support of land development schemes to enhance soil productivity, in support of food security in sub- Saharan Africa. During the Consultation, held in Harare from 8 to 12 December 1997, overview and country papers were presented by senior specialists from Eritrea, Ethiopia, Kenya, Malawi, Namibia, South Africa, Tanzania, Uganda, Zambia, and Zimbabwe, FAO Headquarters and from many national and international institutions. Besides the representatives from the ten countries, an additional ten soil scientists, agricultural land development planners, extensionists and farmers union officials from various Ministry of Agriculture departments of Zimbabwe, as well as eight scientists from the Tropical Soil Biology and Fertility Programme (TSBF), and FAO consultants and resource persons from the UK, Sweden and the International Soil Research and Information Centre (ISRIC) participated in the Consultation. The wide range of participants in the

5 iv consultation reflects the international interest in land degradation in sub Saharan Africa. These proceedings provide very useful information about land degradation in general and the situation in the ten countries of the region. In the light of discussions, recommendations are made to increase exchange of experience and activities in the area of research and technology development, especially the assessment methodologies, extension and training, policies and legislation, strategies, publications and networking.

6 Integrated soil management for sustainable agriculture and food security in Southern and East Africa v Contents SUMMARY REPORT 1 OVERVIEW PAPERS 15 Land degradation with focus on salinization and its management in Africa, by A.M. Mashali 17 Land degradation in relation to food security with focus on soil fertility management, by H. Nabhan 49 Erosion-induced loss in soil productivity and its impacts on agricultural production and food security, by M. Stocking and A. Tengberg 91 Soil degradation assessment and soil conservation inventory on a SOTER basis: Asian experience, by G.W.J. Van Lynden 121 Socio-economic impacts of soil management for sustainable agriculture and food security in Africa; with particular reference to Zimbabwe, by D. Tawonezi and P.N. Sithole 127 Soil and water conservation, soil moisture management and conservation tillage in Zimbabwe, by G. Nehanda 153 COUNTRY REPORTS 177 Eritrea 179 Ethiopia 197 Kenya 211 Malawi 231 Namibia 247 South Africa 263 Tanzania 295 Uganda 319 Zambia 337 Zimbabwe 355 page

7 vi Annex 1 Opening and closing addresses 383 Annex 2 Programme 389 Annex 3 List of participants 393 Annex 4 Maps 397

8 Integrated soil management for sustainable agriculture and food security in Southern and East Africa vii Acknowledgements The contribution through country and overview papers by the country specialists and resource persons is greatly acknowledged. The efforts of AGRITEX staff, Messrs H.Nabhan, A.Mashali, C.F Mushambi, A.Savva and Ms K. Franken in the organization of the Expert Consultation are highly appreciated. Special thanks are due to Messrs H.Nabhan, A.Mashali, M.Gosi,and A.R. Mermut for the compilation, review and editing of these proceedings.

9 Integrated soil management for sustainable agriculture and food security in Southern and East Africa 1 Summary report Nearly one thousand million ha of vegetated land in developing countries are subjected to various forms of degradation, resulting in moderate or severe decline in productivity. About 490 million ha in Africa are affected by different types of degradation from the approximately million ha total land area in Africa. Of this total land, 72% (2 146 million ha) are problem soils with different production constraints (soil acidity, vertic properties, low fertility, shallow soils, saline and poorly drained soils). Poor and inappropriate soil management is the main cause of physical and chemical degradation of cultivated land. Soil degradation is the most serious environmental problem affecting sub-saharan Africa (SSA). In many parts of SSA fallow periods are being reduced considerably and farmers are increasingly cultivating marginal lands susceptible to various forms of degradation. Increasing population pressure, particularly in vulnerable regions has caused serious soil productivity decline especially under extensive farming practices. This is manifested by declining yields, decreasing vegetation cover, salinization, fertility decline and increasing erosion. With recent emphasis on the priority programme of FAO on Food Production in Support of Food Security (SPFS), issues related to land degradation and its negative impact on food production as well as land improvement for enhanced productivity are receiving special attention. Rectifying soil degradation and sustaining crop production through appropriate management and conservation are, therefore, important components in the effort towards security. Successful experience and initiatives for soil improvement in specific countries or socio-economic and agroecological environments have taken place but their wider dissemination for the benefit of other countries, even in the same region, is rather limited. There is an urgent need to develop and implement sub-regional and national programmes, as well as projects at community level to control land degradation and to improve land productivity. Therefore, the FAO Land and Water Development Division (AGL), in collaboration with the Subregional Office for Southern and East Africa (SAFR) and the Agricultural Technical Extension Services (AGRITEX) of Zimbabwe, has organized this Expert Consultation The FAO Subregional Office for Southern and East Africa represents 21 countries. Of these, four are in the Indian Ocean and 17 are within the continent of Africa (Figure 1). Out of the 21 countries, ten were given the opportunity to participate in this important Expert Consultative Workshop on Integrated Soil Management for Sustainable Agriculture and Food Security. The main objectives of the workshop were: Discuss the status of land degradation under contrasting agro-ecological and socio-economic conditions. Exchange experiences on constraints for controlling land degradation and examine possible solutions to overcome these constraints. Develop national and sub-regional programmes in support of land development schemes to enhance productivity in support of food security in the region.

10 2 Summary report FIGURE 1 Countries served by the FAO Subregional Office for Southern and East Africa Reversing the process of soil degradation and sustaining crop productivity through soil management and biodiversity conservation are important aspects of food security. Although cost effective options are available, there is a need to increase the awareness campaign at high policymaking level as well as maintain the determination of agriculturists to achieve their goals. It is, therefore, important to document the information on the extent of soil degradation, its biophysical, economic and social impacts as well as successful examples of soil improvement programmes within the region. ATTENDANCE The Expert Consultation was attended by senior specialists from ten African countries of the Subregion for Southern and East Africa: Eritrea, Ethiopia, Kenya, Malawi, Namibia, South Africa, Tanzania, Uganda, Zambia and Zimbabwe. Besides representatives from the mentioned countries, some ten soil scientists, agricultural land development planners, extension and farmers'

11 Integrated soil management for sustainable agriculture and food security in Southern and East Africa 3 unions from relevant departments of Zimbabwe, as well as eight scientists from the Tropical Soil Biology and Fertility Programme (TSBF) - Kenya, Malawi, Tanzania Zambia, Zimbabwe and Uganda - and officials from FAO Headquarters (2), FAO Subregional Office for Southern and East Africa (2), Regional Office for Africa (1) and FAO consultants and resource persons from England, Sweden and the International Soil Research and Information Centre (ISRIC) participated in the Consultation, with a total of 35 participants. OPENING OF THE EXPERT CONSULTATION On Monday, 8 December, after registration of the participants, the Opening Session took place at St. Lucia Park Training and Development Center, where H.E. the Minister of Lands and Agriculture, Cde Kumbirai Kangai and the Chief of the Soil Resources, Management and Conservation Service of FAO Headquarters, Dr P. Koohafkan (on behalf of the Land and Water Development Division of FAO, and the Southern and East Africa Subregional FAO Representative, Ms V. Sekitoleko), addressed the Expert Consultation. The opening session was followed by three overview papers on (i) Land degradation and its impact with focus on salinity and fertility decline and their management; (ii) Erosion induced loss productivity, its implication on land use and food security; and (iii) Methodologies of soil degradation assessment with focus on GLASSOD /SOTER using the Asian experience (ASSOD). COUNTRY PAPERS Three technical sessions were devoted to discussion of country papers on: Evaluation of country production and projected demands Evaluation of per caput arable land, crop yields and causes of yield stagnation Assessment of soil degradation: its causes and its bio-physical and socio-economic impact Available technological options for controlling soil degradation and for productivity Successful cases on improved soil management scheme and reasons for success Institutional, socio-economic and policy issues related to land resources and degradation. Three papers were also presented from Zimbabwe on: Socio-economic aspects of soil management for sustainable agriculture and food security in Africa Soil and water conservation, soil moisture management and conservation tillage in Zimbabwe Water harvesting and small-scale irrigation. OTHER BUSINESS A video show of the 14th meeting of the Soil Science Society of East Africa (SSSEA) on "Enhancing farmers efforts to combat soil degradation has been demonstrated to the Consultation participants. The video indicated that scientists, administrators, policy makers and farmers were concerned with the issue of soil degradation in the sub-region (Uganda and Tanzania participated in that meeting). Commitment of Uganda Government and other sub-regional governments to the issue of soil degradation was outlined. The SSSEA members were happy to note that FAO would

12 4 Summary report respond to the deterioration of soil productivity through the establishment of a new Southern and East Africa Subregional Network on Management of Degraded Soils. One day (10 December) was devoted to field visits and on-site discussions. The participants were driven to Mangwende Communal Area in Murehua and shown three programmes on soil fertility: The effect-of low and high quality manure on the improvement of soil fertility on crop. The effect of storage practices on the quality of communal area manure. The use of legume inoculant on a crop of soybeans and the effect of residual N (Nitrogen) on crop rotation. After discussions on each programme, the participants were shown active and reclaimed gullies in the same area. Lastly, the group visited a stream bank conservation programme, where farmers are encouraged to cultivate pieces of land situated away from the river bank. On this piece of land, these farmers were provided with fencing materials by the Department of Natural Resources and a well for drawing water was dug using funds from a donor agent. The water is used for irrigating the gardens. PARTICIPATORY WORKING GROUP DISCUSSIONS One and-a-half days have been devoted to group discussions. The participants were divided into three groups to discuss the following issues: present and outlook for food production and security in the participating countries, identification of land degradation and degraded soils - quantification of magnitude and distribution, assessment of human-induced soil degradation, proposals, methodologies for assessment. Soil vulnerability to different degradation processes (as early warning system). If methodologies are available, how they can be used for the sub-region (data availability to carry out such assessment), dominant types of land degradation, (chemical, physical, biological), causes and processes, research, measuring, interpretation and prediction methods including new technologies (modelling, GIS, expert system, decision support system, remote sensing, etc.), bio-physical-environmental and socio-economic impacts of soil degradation: (i) evidence and indicators of impacts of degradation on productivity, and (ii) assessment of economic impacts of degradation, technologies available for improving the productivity of degraded soils: constraints and solutions. Sustainable integrated management of degraded soils (techniques): (i) available technologies for addressing or controlling various types of degradation: and physical degradation - fertility decline salinization and (ii) analysis of factors which are limiting wider adoption of improved technologies to above major types of degradation, policy and land tenure issues: institution set-up and coordination at local subnational and national level, farmers' participation in land improvement schemes, role of associations, cooperatives, extension services: (i) government responsibility: monitoring of soil degradation, control at country and regional level (regulation, legislation, etc.) and (ii)

13 Integrated soil management for sustainable agriculture and food security in Southern and East Africa 5 influencing, decision makers/increasing awareness about land degradation and solutions for land productivity improvement, research and monitoring requirements: (i) applied research, decision support system, integrated approach, monitoring system, requiring more research, mechanism, programmes and government support and interest, (ii) the role of private (multinational) companies, large farms, and (iii) the role of farmer associations, organizations, national and regional plans for improvement and control of soil degradation, proposal for a network on management of degraded and problem soils in the subregion - objectives, activities, mechanisms, membership and expected outputs including newsletters/publications, pilot field activities (demonstration of trials on improved management techniques), training, workshop, etc. At the end of these group discussions, three summary reports were produced. RECOMMENDATIONS In the light of the discussions, the Expert Consultation agreed on the following recommendations as the basis of future activities. Technologies and Research Further investigation and understanding of existing indigenous technologies, Compiling available technologies, Pursue integrated and sustainable soil management issues such as biophysical, economic and social viability, Develop problem oriented and farmer participatory research approach to tackle land degradation problems in the sub-region. Extension and Training Both demonstrations and training of people (research, extension, farmer) should be part of the introduction of new technologies, Technologies should be made available to farmers through extension programmes in the country wherever applicable, Support for farmer conservation groups. Policies, Institutions and Laws Formulate effective land tenure and land use policies to create conducive environment for improved integrated management technology for land degradation control, Creation of enabling policies to encourage management, conservation and sustainability of land resources should include land tenure, environmental protection and a set of framework for conservation, Countries should commit themselves to review natural resources and implementation of the policies,

14 6 Summary report People should be trained to implement these policies, Create strong institutions to backstop management and conservation initiatives at local level, Strengthen institutional capacity to adopt and utilize new and improved technologies. Strategies Causes of food insecurity should be identified as well as strategies to address these causes and the possible constraints to these strategies. Models Prediction models should be used as possible scenarios to monitor land degradation. Standard Analytical Methods Quality control and standardized analytical methods are required to make comparison of results between countries within the sub-region. Assessment of methodologies Available methodologies for the assessment of land degradation include WOCAT, GLASOD, ASSOD, etc. It is recommended that in using similar methods for the sub-region, the following should be considered: The scale on which the information is presented should be revised on a regional basis, utilizing the polygon concept as is done in Asia studies (ASSOD), Countries should concentrate on the quantification of land degradation processes, Countries should consider the utilization of the ASSOD impact evaluation methodology and modify it when deemed necessary for the sub-region conditions, Existing impact assessment technologies may be reviewed and utilized wherever applicable (reference Jan de Graaff, Stocking, etc.), The state-of-the-art of existing technologies should be compiled through modified and more effective mechanisms suitable for the sub-region, i.e. modification of WOCAT methodologies. Projects First priority: projects to keep good land conserved. Dissemination and implementation of good practices, Rehabilitation of degraded land - target "hot spots" and "potential hot spots. Use of best technologies (irrigation, improved fallow, etc., adapted to local social and economic circumstances), Use of food security scenarios as tools to design and target implementation projects and appropriate interventions. Publications Prepare a state-of-the-art/overview document on management of degraded soils in Africa with particular reference to the Southern and East Africa sub-region conditions.

15 Integrated soil management for sustainable agriculture and food security in Southern and East Africa 7 Networking The group agreed to create a new network on the management of degraded soils. The first activity of this network should include the evaluation of ongoing networks in the region as TSBF (Tropical Soil Biology and Fertility), ALASA, CIMMYT (soil fertility), etc. Based on this evaluation, activities of the proposed network will be identified including supplementary field work to control other land degradation processes not included ongoing networks, newsletters, internet, workshops, farmer-to-farmer visits and prediction models. GROUP DISCUSSION REPORTS Group discussion report for Group One (Tanzania, Kenya, Ethiopia, Eritrea) Outlook of food situation Eritrea and Ethiopia experience food deficit. Tanzania and Kenya are self-sufficient at country level but not at household level. All countries require improved technology for future food production. Types and extent of soil degradation Type Eritrea Ethiopia Kenya Tanzania Erosion Fertility decline Acidification Sodicity/salinity Compaction and crusting Water logging : Low, ++ : Moderate, +++ : High Technologies applied to control degradation Technology Eritrea Ethiopia Kenya Tanzania Soil & water conservation Minimum tillage + + Inorganic fertilizer Liming + Manure & organic + fertilizer BNF Agroforestry : Low, ++ : Moderate, +++ : High Assessment of land degradation Kenya has identified indicators of land degradation but the assessment techniques need to be developed in the four countries. Modelling and GIS facilities are in place but need to be utilized effectively. The socio-economic impact of degradation in the four countries is high. However, the quantitative assessment has not been adequately undertaken. Soil degradation indicators identified Yield decline Reduced fallow periods

16 8 Summary report Deforestation Encroachment on marginal land Erosion features (gullies, siltation of dams) Loss of biodiversity Shrinkage of agricultural land Availability of technology Technologies Eritrea Ethiopia Kenya Tanzania Soil & water conservation Minimum tillage Inorganic fertilizer Liming Manure & organic + fertilizer BNF Agroforestry Salinity reclamation : Low, ++ : Moderate, +++ : High Adoption of technologies Technologies Eritrea Ethiopia Kenya Tanzania Soil & water conservation Minimum tillage Inorganic fertilizer Liming Manure & organic + fertilizer BNF Agroforestry Salinity reclamation : Low, ++ : Moderate, +++ : High Constraints limiting adoption Soil and Water Conservation: Labour shortage, lack of training, lack of awareness, decrease in size of agricultural land, lack of credit, poor extension, poor infrastructure, poor linkage, land tenure systems Minimum Tillage: Lack of information, lack of extension services, lack of inputs (herbicides and equipment) Inorganic Fertilizers: High costs, limited availability, lack of knowledge, adverse effects on soils Liming and Liming Materials: Not adequately researched, lack of information, high costs, lack of awareness on acidity problems Manure and Organic Fertilizers: Unavailability, alternative uses (fuel), lack of transport, poor storage, preservation, ow nutrient content Biological Nitrogen Fixation: Lack of adequate research, lack of seed inoculants, poor fixation (low P), lack of information

17 Integrated soil management for sustainable agriculture and food security in Southern and East Africa 9 Agroforestry: Competition with crops (light, moisture nutrients), incomplete package, lack of awareness, land shortage, lack of seedlings, lack of convincing results Salinity reclamation: Lack of awareness, technology not well developed, high input costs Policy issues Land use policies and tenure systems exist in the four countries but they vary Existing instruments to enforce land use policies are not effective Farmer participation in all countries exists, but needs to be further promoted Cooperatives and farmer associations exist but they are poorly managed The ratio of extension/farmers is very wide and at the same time facilities for effective extension are very limited Research and monitoring requirements Private sector supports research on cash crops in Kenya and Tanzania All research in Ethiopia and Eritrea is supported by Government NGOs are actively involved in research in all countries Applied research, decision support and monitoring systems are in place in the four countries, but they need to be strengthened National and regional plans Regional Programmes in Soil and Water Conservation include IGAD, ICRAF, CAHI (AHI, AFRENA), SWNM (soil, water, nutrient management and others) Group discussion report for Group Two (Zambia, Zimbabwe and Uganda) Status of food security Issues and problems National: seasonal fluctuations in food security - imports of food, post-harvest storage and distribution Subnational: accessibility and availability, post-harvest storage and distribution Type of food, preference: Matoke (Uganda), Maize - monocrop (Zimbabwe and Zambia) Household: affordability and availability e.g. draught power h/h structure, entrepreneurship/resources/land, labour, capital, seasonal deficits, access to technology Does land degradation cause food insecurity? How? Fertility decline Population migration

18 10 Summary report Shift from cropping to livestock which promotes overgrazing Higher albedo and higher soil surface temperatures Greater vulnerability to drought Positive effects of land degradation (trigger) Adaptation Diversification Technology uptake and intensification Examples from the region: smallholder irrigation (Zimbabwe - Mvuma), banana mulching (Uganda - Kabale), agroforestry (Zambia, Chipata), smalholder irrigation (Uganda - Mbuka). Conditions for positive outcome Enabling policy environment Institutional and legal framework Political (in)stability Marketing and economic incentives Degradation Case Studies Hot Spots Zambia: Southern province, smallholder rainfed monocropping of maize (fertility decline and soil erosion) (4 to 5 years of cropping before critical level is reached). Farm size: ha Soil type: Acrisol Crop: maize Erosion rates: 20 tonnes/ha/year Farm family: 2 adults + 4 children Production potential: 3,600 kg/ha Zimbabwe: North eastern part (Mutoko), natural region 4, soil erosion Soil type: Acrisols Farm size: 1-2 ha Erosion rates: tonnes/ha Crop: Maize Farm family: 2 adults + 4 children Production potential: 3 tonnes/ha Uganda: Kabale, soil erosion because of steep slopes (water erosion) Crop: Sorghum (less susceptible to bad conditions than maize) Soil type: Ferralsol Erosion rate: tonnes/ha Yield potential: 2 tonnes/ha Farm size: 1 ha

19 Integrated soil management for sustainable agriculture and food security in Southern and East Africa 11 Successful Spots Uganda: Nangabo (near Kampala) Local institutions and strong farmer-to-farmer interaction Access to technology Good marketing infrastructure Crop: sweet potatoes Management: crop rotation, mulching, livestock interaction Zimbabwe: smallholder irrigation in Mushandike near Maswingo, 1 ha per farmer, abandoned dryland farming in surrounding areas Crops: maize and rice Soil type: Cambisol Erosion rate: tonnes/ha Yield potential under irrigation: 6-7 tonnes/ha Zambia: Eastern Zambia, Saeli, Chipata South, maize - previously serious soil erosion Soil type: Cambisols, 5% slope (pockets of Acrisols) Agroforestry technology approach Farm Size: 0.25 ha Erosion rate: 45 tonnes/ha before, now 5-10 tonnes/ha lots of biological measures Yields now: 4.5 tonnes/ha (formerly 1.5 tonnes/ha) crop rotation Potential Hot Spots: Zambia: northern province (acidification) Soil type: Ferralsol/Acrisol Sub-humid, shifting cultivation zone Uganda: Mount Elgon/ Mbale area (water erosion on steep slopes) Zimbabwe: Zambezi Valley, shallow and erodible soils, tsetse clearance encourages immigration General Degradation Issues Fertility depletion - presently N, P, and S deficits (cropping, erosion, leaching, humification), potentially K by the same processes Organic matter depletion - affects plant available water, soil structure, erodibility, nutrient supply, biodiversity, soil moisture and soil humidity (erosion, burning, conventional ploughing) Acidification - Al toxicity, nutrient imbalance, P-fixation (leaching, acid parent material, cropping and organic matter depletion, fertilizers) Devegetation - wind and water erosion, siltation, desertification, reduced base flow of rivers, reduced biodiversity and ozone depletion, organic matter and nutrient supply (shifting cultivation and shortened fallow cycle, wood fuel, overgrazing, construction, fire, land clearing)

20 12 Summary report Recommendations Technologies, research and monitoring Further investigation and understanding of existing indigenous technologies Compiling (inventorying) available technologies Integrated sustainable soil management - biophysical, economic and social viability Policies, Laws, Institutions, and Extension Formulation/ Creation of enabling policies to encourage conservation and sustainable land use should include: land tenure, support for farmer conservation groups - need to set a legal framework for conservation rather than setting it against degradation Creation of strong institutions to backstop conservation initiatives at local level Networking Sharing information, experiences, good practice and expectations Formalize and strengthen existing networks between and among all stakeholders (not only between scientists), e.g. newsletters, internet, forums, workshops, farmer-to-farmer visits Networking the networks at local level Projects First priority: projects to keep good land conserved through dissemination and implementation of good practice Rehabilitation of degraded land to target hot spots and potential hot spots through use of best technologies (irrigation, improved fallows etc. adapted to social and economic circumstances - see Table 1) Construction of food security scenarios to design and target implementation projects and appropriate interventions Group discussion report for Group Three (Malawi, Namibia, Zimbabwe, South Africa) Identification, quantification, extent, distribution and assessment of land degradation For Malawi, Namibia, Zimbabwe and South Africa the major forms of degradation are erosion and fertility decline and depending on the country soil acidity (South Africa), sodicity and salinity (Namibia). There is doubt on the validity of the assessments since it was done for some countries qualitatively and also only for cereal production. With certain reservations the countries agreed that the information on the above topics is acceptable when the heading of Table 3 (given in Summary analysis of country papers by C.F. Mushambi; page 175) is changed to include for cereal production and the footnotes may be changed as follows: (i) sodicitv/salinity to sodication/salinization; (ii) causes of degradation be changed to include impacts; (iii) nutrient loss due to erosion be added as an indicator of soil fertility decline and (iv) that improper irrigation management be added as a cause of sodification and salinization.

21 Integrated soil management for sustainable agriculture and food security in Southern and East Africa 13 TABLE 1 Examples of best practice technologies Technology (examples) Conservation tillage (minimum tillage, including ripping, subsoiling and residue management and ridging) Improved fallow (green manure, cover crops - Stylo) Soil amelioration (liming, manuring, composting, inorganic fertilizers, termite earth) Grazing management (zero grazing, short duration, paddocking, improved pastures - legumes, perennial grasses) Irrigation (surface - canals, borders, basins; sprinkler; trinkler/drip (micro)) Contour bunds; grass strips and terraces Crop rotation (grass fallow, sweet potatoes) Conditions - Weed control - herbicidal or mechanical - Grazing control - Appropriate equipment - Research station only to date/ more on-farm research is needed - Sufficient land - Not becoming invasive/ a weed - Integration with livestock - Availability and cost of materials - Expert knowledge - Analytical services - Skills, technical knowledge - Materials - Sufficient land - Water - Community participation - Veterinary service - Water availability - Capital - Knowledge and technology - Suitable land and soil - Community participation - Institutional support - Labour - Equipment - Land - Enough land - Labour for mounding Bio-physical and economic impacts Quantitative data on impacts are not available for many degradation processes. Outlook for food production and security The production and requirement data (see below) presented are open to criticism. A certain time frame might not be representative of the true picture. We should not get involved in detailed food production scenarios since other institutions are already doing this. It is not to say that national food security figures are relevant to household food security figures. Technologies available for improving the productivity of degraded soils Networks are absent for inventories of existing technologies. Factors limiting application of technology are: (i) lack of information; (ii) cost and (iii) lack of knowledge with respect to cost-benefits (illiteracy). Research and monitoring requirements There is in general a lack of expertise/skills to utilize new technologies and also an unavailability of these technologies exists.

22 14 Summary report Policy and land tenure issues, national and regional plans There is a need for countries to make evaluations of existing policies on land use planning, incorporating sustainable utilization of natural resources. Networks and project proposals/programmes RSA Sustainable Utilization of Natural Resources; Biodiversity Namibia Ecosystems Conservation and Protection Programme; Agro-ecological Zone Programme Regional ELIMS

23 Integrated soil management for sustainable agriculture and food security in Southern and East Africa 15 Overview papers

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25 Integrated soil management for sustainable agriculture and food security in Southern and East Africa 17 Land degradation with focus on salinization and its management in Africa Recent estimates indicate that the global demand for food, fibre and bio-energy products is growing at an annual rate of 2.5% and that of developing countries at 3.7% (FAO 1993). World population has doubled in the past 40 years and may double again in the next century to approach 11 thousand million by the year 2100 (World Resources Institute 1992). The population in Africa is expected to increase to million in Historical evidence suggests that an annual growth in output of only 1% can be expected from area increase at global level. Hence optimization of the productive potential of land including degraded land must form a major contribution to meeting the increased demand. However, the greatest challenge for the coming decades lies in the fact that many production environments are unstable and degrading. At risk from starvation, farmers are forced to strive for maximum production from the limited land resources available; this is leading to neglect of the long-term husbandry needs of the soil and water resources. Exhaustion of these resources is the result: decrease of inherent soil fertility, erosion by wind or water and salinization. Africa's lands are suffering from poor and inappropriate land management resulting in rapid land degradation, massive soil loss, falling yields, deforestation, the disruption of water resources and the destruction of natural pastures. About 490 million hectares in Africa are affected by different types of degradation. In rainfed areas, fallow periods are declining below safe limits and marginal land and problem soil with severe production constraints are being put under cultivation in an attempt to meet demands without adoption of proper and efficient water and soil management practices. Of the approximately million hectares total land in Africa, million hectares are problem soils (72%) with different production constraints (soil acidity, vertic properties, low fertility, shallow soils, saline and poorly drained soils). On irrigated lands, improper water use and system management not only detract from attainment of potentials, but also cause productive land to be withdrawn from cultivation through waterlogging and increasing salinity and sodicity. Salinization in Africa is one of the degradation processes and affects widespread areas mainly in arid and semi-arid regions. Drought combined with the different forms of land degradation is seriously contributing to considerable yield decline and loss in food production, and hence the food security at household and country level, particularly in countries which cannot easily finance increased need of food imports. Land degradation is proceeding so fast that few African countries can hope to achieve sustainable agriculture in the foreseeable future. A.M. Mashali Technical Officer, Soil Reclamation, Soil Resources, Management and Conservation Service, Land and Water Development Division, FAO, Rome, Italy

26 18 Land degradation with focus on salinization and its management in Africa Neither traditional systems of using the land, nor the responses of traditional societies to increasingly severe pressures on the land, have been able to cope with the rapid growth of population and degradation processes in Africa for most of this century. The problem is usually identified only after the situation has become serious. Large quantities of soil have already been lost and the productivity of land seriously impaired. Governments have to recognize that their productive land is a limited and irreplaceable resource which should be carefully managed and protected against all forms of degradation and thus desertification. Only when the seriousness of degradation is recognized and its causes properly identified is it possible to develop agricultural practices and management measures that will ensure safe use of the land. Unfortunately wider dissemination of results from successful experiments and initiatives for soil improvement of degraded land in one country for the benefit of other countries (even in the same region) is rather limited. In order to alert policy makers, there is a need to provide evidence and justification for corrective methods which are based on in-depth assessment of the extent, severity of land degradation and their economic and social impacts. Issues related to land degradation and its negative impacts on food production and food security as well as development of appropriate technologies to enhance productivity of degraded soils are receiving special attention and are an important part of the priority programmes of FAO. DEFINITION OF SOIL DEGRADATION, DESERTIFICATION AND SALINITY PROBLEMS Soil degradation and desertification Soil degradation is defined as a "process which lowers the current or the potential capability of soil to produce (quantitatively or qualitatively) goods or services". Soil degradation implies a regression from a higher to lower state - a deterioration in productive capability. The process is not necessarily continuous and may take place between periods of ecological stability or equilibrium. It is usually a complex process in which several features can be recognized as contributing to a loss of productive capacity. It can result from land uses or from processes arising from human activities such as: erosion, deterioration of physical, chemical and biological properties of the soil or long-term loss of natural vegetation. Recently degraded land is defined as land which due to natural process or human activity is no longer able to properly sustain an economic function or the original natural ecological function. Vast areas of Africa continue to be eroded and the degradation of the arid and semi-arid and dry sub-humid regions becomes so serious (resulting from adverse human activities and climate variations) that a new word, desertification, was coined to describe the gravity of the situation. Soil degradation processes whether chemical, biological or physical may occur simultaneously or sequentially and they are interrelated. A definition of desertification is "the intensification or extension of desert conditions". It is a process leading to reduced biological productivity with consequent reduction in plant biomass and destruction of the equilibrium of soil, vegetation, air and water in the areas subject to edaphic or climatic aridity (FAO 1984). Desertification hazards refer to the natural susceptibility of the land to desertification and manmade factors (ISRIC/UNEP 1990). It is considered as a comprehensive expression of economic and social processes as well as those of natural or man-induced processes. An important difference between soil degradation and desertification is that soil degradation is not necessarily continuous; it takes place over relatively short periods and can be reversed. Also desertification or the danger of it, is confined to the arid, semi-arid and sub-humid areas, whereas soil degradation can occur in all climates. Furthermore, certain processes important to the concept of soil degradation are not considered desertification, i.e. waterlogging, depletion of plant nutrients and acidification.

27 Integrated soil management for sustainable agriculture and food security in Southern and East Africa 19 Soil salinization Soil salinization as a process of land degradation is defined as the accumulation of excess salts in the root zone resulting in partial or complete loss of soil productivity and eventual disappearance of the vegetation. Salt-affected soil is simply defined as a soil that has been adversely modified for the growth of most crop plants by the presence of soluble salts, exchangeable sodium or both. Any quantitative definition, however, must be arbitrary because of the broad range of crop salt tolerance. Salt-affected soils are normally divided into three broad categories: saline, sodic and saline sodic. Other categories of salt-affected soils though less extensive are commonly met in different parts of the world and include acid sulphate soils, acid soils, degraded sodic soils and magnesium solonetz. The problems of soil salinity occur in all continents and under all climate conditions. They are most widespread in the arid and semi-arid regions, but salt-affected soils also exist extensively in sub-humid climates, particularly in coastal regions where intrusion of seawater through estuaries and rivers, and through groundwater, causes large-scale salinization. Soil salinity is a problem in irrigated lands particularly where saline water is used for irrigation. Salinity problems occur as well where crops are grown under rainfed conditions. There salinity has several local names, but is most commonly known as dryland salinity or saline seeps. Although weathering of rocks and primary minerals is the main source of all salt, salt-affected soil rarely forms through accumulation of salts in situ. EXTENT OF LAND DEGRADATION, DESERTIFICATION AND SALINIZATION Land degradation and desertification Though soil degradation is largely manmade, its pace being governed primarily by the speed at which population pressure mounts, irregular natural events, such as droughts, exacerbate the situation. Such a sequence of events is not just a thing of the past. In many countries of the tropics and sub-tropics it is happening right now, and at an alarming scale. The 1982/1985 drought, for example, had a dramatic effect on the speed of land degradation in most African countries. Human activities usually aggravate the effect of the physical processes leading to desertification through an inadequate system and policy of land tenure, bad communications, and lack of awareness of acute problems and economic and social conditions. Much of Africa's land base is environmentally delicate and easily damaged. Large areas of cropland, grassland, woodland and forest are already seriously degraded. FAO reported in 1981 that in Africa north of the Equator more than 35% of the land was affected by either erosion or salinization. While it is now generally recognized that land degradation in general, and soil erosion and salinization in particular, are widespread and serious, very few reliable data are available on its extent or degree. Part of the problem is that much of the available data are reported in different ways and not in readily comparable forms (Sanders 1991). An indication of the extent to which the African continent (Figure 1) is subject to soil constraints is given in Table 1. It should be noted that the extents shown in this table are not cumulative since certain constraints overlap one another (FAO 1986). The table indicates that major constraints are caused by steep slopes and erosion. In semi-arid areas where exploitation of the land has continued for thousands of years, accumulation of soluble salts created a serious constraint to production, particularly in Egypt, Libya, Morocco, Tunisia, Somalia, Algeria, Sudan, Ethiopia, Eritrea, Botswana, Chad, Kenya, Tanzania and South Africa. Table 2 gives a summary of most degradation problems in the six climatic regions of Africa.

28 20 Land degradation with focus on salinization and its management in Africa FIGURE 1 Main agro-ecological zones of sub-saharan Africa More recently ISRIC (International Soil Reference and Information Centre), under the aegis of UNEP and in collaboration with FAO, has produced a World Map of the Status of Human- Induced Soil Degradation at a scale of 1:10 m (ISRIC/UNEP 1990) known as GLASOD. It identifies 4 degrees of degradation (light, moderate, strong and extreme). Five types of human intervention were identified as resulting in soil degradation: deforestation and removal of natural vegetation (579 million hectares), overgrazing of vegetation by livestock (679 million hectares), improper management of agricultural land (552 million hectares), over exploitation of vegetative cover for domestic use (133 million hectares), and industrial activities leading to chemical pollution (32 million hectares). According to GLASOD, 1964 million hectares of agricultural land worldwide are degraded (Table 3), of which 494 million hectares (25%) in Africa. Table 4 gives an indication of the extent and severity of land degradation problems in Africa.

29 Integrated soil management for sustainable agriculture and food security in Southern and East Africa 21

30 22 Land degradation with focus on salinization and its management in Africa TABLE 2 Summary of most serious degradation problems by region Region Arable land Grazing land Forest land Mediterranean and North Africa Sudano-Sahelian Africa Humid and Subhumid Africa Humid Central Africa Sub-humid and mountain East Africa Sub-humid and semi-arid Southern Africa Declining soil fertility Wind and water erosion Salinization on irrigated lands Decline in nutrient levels of the soils Decline in soil physical properties Wind and water erosion Decline in nutrient levels of the soils Decline in soil physical properties Water erosion Degraded soil physical properties Degraded soil chemical properties Water erosion Degradation of soil physical properties Degradation of soil chemical properties Water erosion Degradation of soil physical properties Degradation of soil chemical properties General degradation of vegetation both in quality and in quantity Wind and water erosion General degradation of vegetation both in quality and in quantity Wind erosion in subhumid areas Degradation of vegetation Wind erosion in subhumid areas Degradation in quality and in quantity of vegetation Water erosion Degradation in quality and in quantity of vegetation Wind erosion Water erosion Degradation of vegetation as the deficit in fuelwood and timber increases Water erosion on degraded forest land Degradation of vegetation Degradation of vegetation Degradation of vegetation Water erosion Degradation of vegetation Erosion TABLE 3 Human-induced soil degradation for the world (GLASOD) Type Light Moderate Strong Extreme Total Total (Mha) (Mha) (Mha) (Mha) (Mha) (%) Loss of topsoil Terrain deformation WATER Loss of topsoil Terrain deformation Overblowing WIND Loss of nutrients Salinization Pollution Acidification CHEMICAL Compaction Waterlogging Subsidence of organic soils PHYSICAL TOTAL (Mha) (percent)

31 Integrated soil management for sustainable agriculture and food security in Southern and East Africa 23 TABLE 4 Human-induced soil degradation in Africa, GLASOD (in million hectares) Type/Degree Light Moderate Strong Extreme ~Total Water erosion (46%) Wind erosion (38%) Chemical deg (12%) Loss of nutrients Salinization Pollution Acidification Physical degr (4%) Compaction Waterlogging Total* 174 (35%) 192 (39%) 124 (25%) 5 (1%) 494 (100%) TABLE 5 Regional distribution of salt-affected soils in hectares Regions Solonchaks/ saline phase Solonetz/ sodic phase Total % of the total area affected North America 6,191 9,564 15, Mexico and Central America 1,965-1, South America 69,410 59, , Africa 53,492 26,946 80, South and West Asia 83,310 1,798 85, South East Asia 19,983-19, North and Central Asia 91, , , Australasia 17, , , Europe* 9,121 21,105 52, Total 352, , , * The difference between the total salt-affected soils and existing saline and sodic soils in Europe represents the potential salt-affected soils (20856 million hectares). Salinization Land salinization has been identified as a major process of degradation. Information on the exact extent, distribution and degree of degradation is not available for all soils of countries affected by salinity. In some countries, even the existence of these soils was discovered only through a survey or the pressing demand for agricultural utilization of a region. As a general figure about 7% of the total soil surface of the world is covered by salt-affected soils: Australia 45%, Asia 21%, South America 7.6%, Africa 8.5%, North America 0.9%, Central America 0.7%, and Europe 4.6%. Based on the FAO/UNESCO Soil Map of the World, Table 5 shows regional distribution and percentage of salt-affected soils. It should be borne in mind that areas given in Table 5 are not necessarily arable but cover all the salt-affected lands. In Africa the problem is particularly serious in the countries north of the Sahara, in the Sahel, in East Africa, Botswana, South Africa and Namibia. Salt-affected soils are known also in Ethiopia, Kenya, Tanzania and Zimbabwe (Table 6). Table 7 shows that globally more than 76 million hectares of land is human induced salt-affected soil, out of which 52.7 million hectares (69%) is in Asia, 14.8 million hectares (19%) in Africa and 3.8 million hectares (5%) in Europe (Oldeman et al 1991). The four degrees of light, moderate, strong and extreme salt-affected land cover 34.6 million hectares, 20.8 million hectares, 20.4 million hectares and 0.8 million hectares, respectively.