Several case studies from a number of countries were presented during the workshop. They provide a range of specific lessons and results in terms of adaptive management, soil health assessment and capacity building on soil biodiversity and its ecological functions. They refer to different cropping systems, climate conditions and a range of economic situations from low- to high-input agriculture. The ecosystem approach is highlighted as an important concept for improving understanding and management of biodiversity and ecosystem services. Annex 7 presents some background about the ecosystem approach and its links to adaptive management.
Dr Clive Pankhurst of the Land and Water Division of the Commonwealth Scientific and Industrial Research Organisation (CSIRO), Australia, first provided a framework for consideration of the issue of assessment and monitoring. This addressed:
practical approaches and indicators for site assessment of land degradation, land values and services, and off-site impacts;
the capacity to interpret soil health information and develop guidelines and recommendations, using soil ecosystem parameters, simple visual bioindicators and laboratory-dependent bioindicators;
the need for integrative measures that respond to change in soil management in time scales relevant to land users.
He noted that the challenging question is: “What measurements should be made or what can be observed that will help to evaluate the effects of management on soil function now and in the future? There is still no universally accepted list, or minimum data set, of what soil attributes could or should be measured in a given situation.”
Conventional agricultural practices for maintaining and increasing crop and fibre production in many parts of the world are placing pressure on the soil’s capacity to maintain its function. They include increasingly specialized systems and even monocultures, mechanical cultivation and harvesting, high and sometimes excessive and indiscriminate use of mineral fertilizers and pesticides. In other areas, continuous nutrient mining and unsuitable land use systems and management practices are leading to severe soil productivity decline and land degradation. This situation highlights the urgent need to develop a capacity to assess both the degree of functional degradation of the soil and the rate at which it is occurring, and to develop a holistic ‘biological systems management’ approach to soil health and agricultural production.
The introduction was followed by three case studies: on soil health assessment and monitoring for industrial sugar-cane production; on assessment methods using practical tools and existing expertise and materials - the potential use of soil macrofauna as bioindicators of soil quality; and on the measurement of soil respiration as an indicator of soil life.
Cane yields have been declining for many years despite the development of new cane varieties and pesticide controls for known pests (e.g. cane grub). The yield decline was shown to be associated with poor soil health resulting chiefly from the growth of cane as a monoculture and excessive tillage at planting required to overcome soil compaction caused by heavy harvesting machinery. Using soil health indicators (e.g. soil activity and presence of beneficial or detrimental organisms), the extent to which the soils had become degraded physically, chemically and biologically could be demonstrated to cane growers. They were also advised that the only way to reverse this trend was to change the way they manage their soils. An essential component of this process was for researchers to work in close collaboration with groups of cane growers in order to develop a new systems approach. This new approach was based on the incorporation into the farming system of green manure rotation breaks (to improve the biological health of the soil), and reduced tillage (to keep areas trafficked away from growing plants). Demonstration trials together with an economic analysis of the new system compared with the old were also important tools for facilitating this process. The approach was based on providing the cane growers with information concerning the health of their soils and the principles and benefits of maintaining good soil health. It was not designed to provide them with recipes because what might work successfully in one region might not in another.
This sugar-cane experience is a good practical example on the use of bioindicators to enhance management practices. It also provides an important message: not to develop and use soil health indicators as tools to condemn land users for their inappropriate use of the soil resource, but to use them as tools to explain what is happening and facilitate a change towards more sustainable agricultural practices.
(Clive Pankhurst, CSIRO)
It is recognized that each organism in the soil drives soil processes in specific functional domains (e.g. rhizosphere, termitosphere) and that these organisms can be grouped into some 30-40 functional groups. In particular, soil macrofauna are important regulators of soil function and they are easy to measure and identify. The invertebrate communities are sensitive indicators of soil quality. Among the vast diversity of species, adaptive strategies and size range represented, the effects on the soil of the physical activities of a specific group, known as the ‘soil ecosystem engineers’, which also includes large invertebrates, determine activities of other, smaller soil organisms. Human management practices, such as soil tillage, affect soil macrofauna (abundance and diversity) and may create a disequilibrium that can be very difficult to correct. In addition, chemical pollution affects soil fauna adversely. Thus, the composition of faunal communities may be an accurate indicator of diffuse pollution (e.g. by heavy metals and pesticide residues) through indicator species sensu stricto or through bio-accumulators.
PLATE 1. Participatory sampling of soil macrofauna (TSBF methodology) in farming systems of Tanzania - [G. Brown]
Through extensive studies, the IBOY-Macrofauna Network has confirmed that macrofauna is relatively easy to collect. It used participatory methods to involve farmers groups in the process of sampling, collection and identification of soil macrofauna functional groups (Plate 1). The standard method of the Tropical Soil Biology and Fertility Institute (TSBF) was used to collect invertebrates at more than 1 000 sites, with a focus on tropical areas. Results so far have shown that macrofauna functional groups correlated very well with different soil chemical and physical situations as well as management conditions (in particular, organic matter inputs and mineral fertilization, e.g. N). This work has produced a database that characterizes more than 42 taxonomic groups of invertebrates and associated site variables (cropping system, management practices, season, climate region, soil type, depth, etc.).
FAO considers this macrofauna database a useful and unique source of information to build on practical indicators and index on macrofauna and has committed support for the further analysis of the database. Further analyses of these results promise the identification of groups that are specific indicators for a given type of system, including development of an index, considering a set of variables. Further analysis and validation is needed in order to consider the application limits and the standardization of such indices and potential macrofauna indicators. The aim is to make findings available in a practical guideline for farmers and technicians showing linkages between specific organisms, management and beneficial or detrimental effects on soil and plant health. This guideline will then be integrated into a manual on soil productivity improvement. The need to keep this database up-to-date was also raised.
(Patrick Lavelle, International Biodiversity Observation Year (IBOY) - Macrofauna Network)
A simple method for farmer assessment of overall biological activity of the soil and soil health has been tested in Bhutan and Kenya. This method is based on soil respiration (oxygen uptake or carbon dioxide production). It provides information on soil life activity, and can provide the basis for management decisions and for raising farmer awareness about the living nature of soils. A laboratory or field respirometer provides a measure of biological activity, nutrient mineralization, toxicity of chemicals to soil organisms and management effects. In addition to chemical and physical measures, soil respiration as a biological measure is included in the soil-quality test kit. There is a need to consider temporal and spatial changes and environmental conditions (temperature and moisture) and to measure them at comparable points in the crop cycle. Various soil test kits are available for such measurements. For example, the Solvita soil life kit indicates soil respiration by a colour indicator (http://www.solvita.co.uk/). It enables estimation of annual N release based on soil biological activity, evaluation of organic matter sufficiency of soils and overall judgements for ‘soil quality’ interpretation. This test procedure is as reliable as laboratory test methods and is currently the only alternative to more expensive Dräger tube procedures used in some soil investigations (US$125 excluding VAT for 12 test pack, US$97 for refill). The USDA Soil Quality Test Kit Guide (an 82-page booklet) contains procedures for 12 on-farm tests, interpretation, data recording sheets and details on how to build the kit. It can also be purchased (US$500) including initial supplies for tests of soil respiration using the Dräger tube, as well as salinity, aggregate stability, soil structure, infiltration, pH, earthworms, soil texture, bulk density, soil nitrate, compaction, water quality (http://soils.usda.gov.sqi/). However, these kits focus largely on chemical analysis.
(Martin Wood, University of Reading, The United Kingdom)
These three case studies stimulated discussion by the working group on several ideas and approaches regarding: sampling and measurement methodologies; interpretation (including definition of minimum threshold values for particular indicators); the frequency with which measurements should be made; and, above all, how to engage land users in the process of using soil health indicators. Special attention was given to methods and sampling procedures and tools. Problems in using soil organisms and their diversity as indicators of soil health include the inherent temporal and spatial heterogeneity of soil organism populations and the unpredictable interaction of soil organisms with climate factors. More comprehensive information on the impacts of different land management practices should be provided. Such information should complement information on soil organisms with other soil biological measures such as plant species and diversity, leaf litter, plant rooting system, and soil organic matter contents throughout the soil profile. Sampling scale and frequency thus affect cost and reliability. Soil bioindicators need to be robust and meaningful, and easy to measure and interpret. Work is needed to confirm which indicators, which types of organism and/or which soil biodiversity functions have these characteristics, in which environments they are reliable and how they can be monitored and the findings interpreted.
For sustainable and productive land management, soil organic matter is a critical factor in most soil types and agro-ecosystems. This is because it reflects not only soil C but also soil moisture retention, nutrient availability, resilience to erosion and the substrate for most soil biological activity. In recent years, increased attention has focused on methods of monitoring soil organic matter or soil C. This has been because of the recognition of the importance of C sequestration in soils to reducing or mitigating greenhouse gas emissions and in response to the Kyoto Protocol of the framework convention on climate change (including offsetting greenhouse gas emissions in other areas under the carbon trading mechanism).
Dr Lijbert Brussaard introduced the issue of adaptive management of soil ecosystems, referring to the proposals of Mr Kofi Annan, UN Secretary General, at the World Summit on Sustainable Development (WSSD, Johannesburg, 2002) and his emphasis on four issues: water and sanitation, energy, agricultural productivity, and biodiversity and ecosystem management, and his recognition of the importance of making knowledge and expertise work in order to achieve the sustainable development goals. Dr Brussaard emphasized the convergence of science and of inclusive technology innovation processes for better integrated crop and soil management. He noted the need to translate science into practice through identifying indicators of system performance that are useful for farmers and land managers in assessing the economic, ecological, environmental and social impacts of their management practices and land use systems. Annex 7 provides further information on the ecosystem approach and its links to adaptive management.
The introduction was followed by a range of case studies on adaptive management. These included: technology innovation for integrated soil and crop management; biodynamic agriculture for desert reclamation; biofertilizers for mixed agriculture in the humid tropics; no-till agriculture for smallholder cropping; integrated pest and nutrition management for (i) armyworm control and (ii) nematode control; the role of soil macrofauna in soil rehabilitation in drylands; interaction between field and landscape levels in regard to conservation, sustainable use and ecosystem services; the use of vermicompost to enhance soil fertility (commercial tea production and horticulture) and the need for a communication and extension strategy for technology transfer; the importance of human dimensions of ecosystems, notably institutions and sociocultural processes and consideration of economic returns and valuing of ecosystem services. Such cases provide information that can be shared as a basis for technology transfer and improved management decisions.
Research on technology innovation processes for more integrated crop and soil management is being conducted through collaboration between the North-South Interdisciplinary Research and Education Fund (INREF), Wageningen, the Directorate General for International Cooperation, The Netherlands (DGIS-NET) and the FAO IPM Facility. In Mindanao, the biodiversity research programme was conducted along a landscape gradient from upland through lowland to coastal areas. It was found that agro-ecological innovations emerge from interactions among actors with potentially complementary roles, especially in marginal areas, where rural people rely on variety and variability and are active in managing the adaptation process. The process of acquiring and sharing information between the private and public sectors is very important and depends on the incentive regime, which will tend to favour certain approaches. Change is stimulated by non-satisfied needs of farmers and identification of options and experimentation to address these needs or problems.
(Lijbert Brussaard, Wageningen University, The Netherlands)
This programme has been extremely successful in reclaiming desert land for agriculture. Through regional cooperation among many actors, farmers and agricultural engineers receive training on the importance of micro-organisms for developing soil fertility. Farmers experience the importance of organic matter and compost (referred to as ‘black gold’) for organic farming and receive training in organic matter management and compost preparation (from small-scale to industrial systems) using agricultural waste and animal manure. Results include over 2 200 ha of biodynamically certified desert locations at the margins of the Nile Valley and elsewhere. The approach is strongly market oriented for the production of organic cotton, medicinal herbs and vegetables. Cotton has recently been intercropped successfully with basil and lemon grass. The project and connected smallholders are following international standards for organic agriculture (the European Community (EC), National Organic Program and Demeter). The added value fulfils standards of European Good Agricultural Practice, and Hazard Analysis and Critical Control Point. The project has recently received the Fair Trade Label award for some of its commodities.
Another network (not presented at Londrina) on organic matter management is the interdisciplinary group on the Management of Organic Inputs in Soils of the Tropics (MOIST), coordinated by Cornell University International Institute for Food, Agriculture and Development, The United States of America. The MOIST was set up to investigate and exchange information on cover crops, green manures, managed fallows and mulches in tropical farming systems. The aim is to optimize the management of organic inputs for harnessing the biological potential of legumes, manures, residues, and soil fauna in order to improve and sustain evolving agricultural systems in Asia, Africa and Latin America. It has developed searchable databases and encourages interregional exchange through seminars, electronic networking and extension materials (http://ppathw3.cals.cornell.edu/mba_project/moist/home2.html).
(Klaus Merckens, Vitality from the Sun (SEKEM): Egyptian Biodynamic Association (EBDA))
This work illustrates the commercial production, trials and extension and adoption of arbuscular mycorrhizal fungi (AMF) inoculants by farmers in Cuba. These aim to overcome problems of soil productivity and yield declines, economic constraints and lack of fertilizers. Practical research was conducted with farmers on the application of AMF, including on-farm trials with many crops (such as coffee, rice, vegetables and soybean) and on different soil types. Capacities are strengthened through agro-ecological fairs, education and extension. Improved organic matter management is central to the functioning of the techniques.
(Eolia Treto, Instituto Nacional de Ciencias Agrícolas)
The exemplary case of the farmer-driven process for the development and adoption of no-till agriculture in Brazil was outlined. A series of damaging frosts catalysed the replacement of coffee systems by annuals and especially monocultures of sorghum and soybean, which led to serious soil and water erosion and nutrient depletion. Initially, physical solutions were sought in the 1970s, until pioneer farmers, such as Herbert Bratz in Londrina, initiated experimentation with no-tillage practices. Research and extension initially criticized the spontaneous adoption of no-tillage agriculture by other farmers. However, after 30 years the no-tillage practices are being applied to millions of hectares of soybean, cotton, maize and sorghum with a range of cover crops (lupin, vetch, Crotalaria, pigeon pea, sorghum, pearl millet, Mucuna, etc.). Good practices of no-till farming provide higher yields through improved organic matter management and allelopathic effects of certain cover crops. An enabling environment is required to catalyse adoption, alleviate risk and promote stewardship and responsibility for the land. The Friends of the Land (earthworm) Club helps raise awareness of environmental concerns of urban and peri-urban consumers and community organizations. A dynamic collaborative process among farmers, extension (IAPAR) and research (EMBRAPA) combined with a supportive environment (farmer-extension-policy) has stimulated adoption by smallholders. (Care is required in interpreting these results as a smallholder farm in Brazil may be 40 ha, whereas a smallholder farm in Asia or Africa may be 0.5-1 ha).
(Ademir Calegari, Agronomic Institute of Paraná (IAPAR), Brazil)
The transition from coffee was initially to macadamia and sugar-cane production, and subsequently to degraded pasture, which was accompanied by a serious rural exodus. This case illustrated the critical issue of economic returns. Where a farming system becomes non-viable, farmers shift enterprises or even abandon farming, with resulting loss of rural economies and livelihoods. In addition to the primary agricultural goals of increased farm produce and sustained productivity, there is a growing need to better illustrate the value of ecosystem services and social and cultural benefits provided by sustainable agriculture. Thus, improved technologies, such as biological nitrogen fixation (BNF) to improve productivity, need to combine with business and environmental management, including the adequate valuation of the ecosystem services provided by farmers.
(Patrick Lavelle)
This case illustrated how plant flavonoids can suppress weeds, pathogens and pests, and promote nodulation and nutrient cycling. Flavonoids have been shown to promote microbial growth and induce nod genes in root nodule bacteria, to provide antibiotic molecules against insect pests and pathogens and suppress certain weeds such as the parasitic Striga. They also mobilize unavailable magnesium (Mg), calcium (Ca) and phosphorous (P) in alkaline soils as shown by the aluminium (Al) concentration in the cluster roots. These non-N-fixing benefits of nodulated legumes are greatest in cowpea, less in soybean and still less in common bean.
(Felix Dakora, University of Cape Town, South Africa)
Through a number of examples, this case emphasized how biomass is the engine for crop productivity and why balanced plant nutrition is crucial for enhanced productivity. The burning of rice- and wheat-straw in much of Southeast Asia (Viet Nam, Philippines, Indonesia and India) has been causing huge losses. Alternatives such as composting are available, depending on conditions. For example, a period of 35-45 days is required to compost dry straw in semi-arid conditions. There is a need to identify appropriate practices for use by cash-poor farmers and to integrate a range of low-cost practices, e.g. no-till with surface mulch, crop rotations and pest-tolerant cultivars. In addition, it is possible to be proactive, for example, seeding the soil with natural allies/beneficial micro-organisms and spraying crops with biopesticides as a prophylactic measure. There are important interactions between plant nutrition and pest management. For example, an increase in soluble N and free protein amino acids in the plant tissues, especially leaves, increases the risk of pest damage.
(O.P. Rupela, International Crops Research Institute for the Semi-Arid Topics [ICRISAT])
his study illustrated several strategies developed to control root-knot nematode on beans (Phaseolus vulgaris L.). The common bean is the most important legume crop in Kenya and the major constraint on bean production is nematode infection, causing yield losses of up to 60 percent. This case demonstrated the potential of organic amendments (chicken manure, compost, neem leaves, baobab remains and farmyard manure) to suppress root-knot nematodes and to increase bean yield in field conditions. The amendments showed varying levels of nematode suppression, with chicken manure ranking as the most effective. In addition, locally isolated Bacillus strains showed potential for use as biocontrol agents of root-knot nematodes. The ability of Bacillus isolates to suppress nematodes can be attributed to reduced egg hatching and modification of root exudates, which interferes with the host-finding processes of the nematodes or produces metabolites that are toxic to the nematodes.
(Nancy Karanja, University of Nairobi, in absentia)
The main purpose of this work was to evaluate the capacity of termites to improve the structure of crusted soils, including their ability to reduce soil compaction, increase soil porosity, and improve the water infiltration and retention capabilities of soils in the Sahel. The stimulation of soil fauna, especially termites, using locally available organic resources (straw, wood materials and manure) is a viable option for improving soil structure in semi-arid regions. Mulch application should be timed to coincide optimally with termite foraging periods, and should anticipate seasonal rainfall events, thereby allowing nutrient release to be better synchronized with plant growth demand. The restoration of a bare sealed soil with very high runoff rates could be seen through measuring pore numbers per square metre of soil surface. This study demonstrated that termites restored crusted Sahelian soils successfully when their bioturbating and decomposing activities were managed properly by careful organic matter additions.
(Abdoulaye Mando, Institut pour l’Environnement et la Recherche Agricole, Institut de Recherche pour le Developpement (IRD), France)
The purpose of this study was to restore soil fertility and improve tea production on six private tea estates in Tamil Nadu, India, using organic matter and earthworms. Trenching prunings, organic material, and earthworms between tea rows (bio-organic fertilization, or FBO) increased yields and profits dramatically and determined that FBO is an affordable tool, adaptable to situational needs and appropriate to commercial management scales from small farms to plantations. The major components of this technological package include: large-scale vermiculture production; adaptable management practices; rearing different functional types of earthworms for inoculation; selecting and placing organic matter by quality and quantity criteria. The current adoption of FBO techniques in very large-scale applications in India can already ensure positive responses of up to 50 percent enhancement in production. Based on the results obtained using FBO, a patent was deposited to protect the technique associated with this treatment. The patent, titled “Fertilization Bio-Organique dans les Plantations Arborees”, was developed by Parry Agro Industries Ltd. in association with the IRD and Sambalpur University. The patent document (ref. PCT/FR97/01363) provides details of the methodology for its application.
(Bikram K. Senapati, University of Sambalpur, India)
This was a case of technology adoption failure. To reduce Al toxicity, sawdust was inoculated with earthworms. This reduced Al toxicity effectively (from 85 to 45 percent exchangeable Al) and improved the cation exchange capacity (CEC) through the extraction of Ca and Mg cations. The technique was used successfully in urban horticulture for the production of tomatoes. However, in Brazil, the promising technology of processing sawdust through earthworm inoculation and use of chicken slurry, although of proven value, did not lead to adoption by the end user. The lack of adoption was believed to be because of an inadequate extension and communication strategy.
(Patrick Lavelle, IRD, France)
This study showed the interaction between field and watershed levels. The strategy to restore the ecosystem was based on the increase of available resident water in soil and the atmosphere, obtained by diversified vegetation (partially deep-rooted perennial plants), its shade, its root activity and the energetic litter for soil biota. The application of different technologies that increase available moisture through diversified plant management on a soil protected by litter and rooting network demonstrated how to improve soil biodiversity, biotic activity and ecosystem services.
(Odo Primavesi, Brazil)
This case emphasized the immeasurable variations of production systems and species diversity and managed landscapes, which comprise a range of human and natural ecosystem types. The relationship between biodiversity level and management level for a range of systems from plantations to mixed systems and unmanaged systems was considered (Figure 1). In Figure 1, Curve I and Curve II represent two extreme possibilities that seem to be unlikely. Curve III is a softer version of ecologists’ expectations. Curve IV seems to be more likely and it is the most interesting from the point of view of biodiversity conservation. Efforts for the sustainable development of these traditional agro-ecosystems should be based on conserving agricultural biodiversity within the system for resilience of the system with concerns for productivity.
This case highlighted the fact that there is no direct relationship between population and land degradation. The importance of institutions and socio-economic and sociocultural processes was emphasized, as well as their interaction with the ecological process.
Workshop participants considered the ongoing work and experiences presented through the above cases on biological management of soil ecosystems. They drew attention to the need to focus on farmers’ needs and on the opportunities to address soil biodiversity as a key element of an integrated soil productivity and land management strategy. It was noted that, in agricultural development, soil knowledge has been restricted largely to soil management for production (crops, pasture, trees) with a focus on the biophysical (structure, texture, soil moisture, organic matter) and chemical dimensions (soil nutrients, salinity, pH, CEC). There is a need to identify and facilitate understanding and the transfer of knowledge on the functioning of the soil ecosystem, including the management of soil biodiversity and its functions, and its adaptation and use for sustainable and productive agriculture.
Source: Swift et al. (1996).
In developing guidance for wider use on the basis of case studies, it was also recognized that there is a need to consider, inter alia: the type of farming system and level of intensification, the agro-ecological zone and the scale of intervention in space (farm, community, watershed) and time (growing season to several years). There is a need to identify the range of stakeholders and to provide practical tools and approaches that link soil quality and health with agricultural productivity and socio-economic considerations (integrated ecosystem approaches). These issues could be reflected in the revised format for the presentation of case studies.
An important consideration for agricultural productivity is the capacity to maintain and restore soil productivity, through nutrient cycling, under different land use and agro-ecological contexts. It is a misconception that the addition of organic matter leads automatically to improved soil structure. In reality, in a lifeless soil, organic matter persists unprocessed, offering little in the way of benefits until the biological components are able to thrive again. Improved soil structure is a consequence of the physical and chemical activity of soil organisms, including their processing of the organic matter through decomposition, and the delivery of available nutrients to the plant or crop.
Farmers may focus on soil biodiversity improvement through manipulations of organic inputs to improve soil fertility in their farming systems, obtain greater incomes and increase their livelihoods. Researchers should work together with farmers towards improvement of ongoing farmer initiatives for crop yield and soil productivity improvement as an immediate strategy for soil biodiversity improvement. Moreover, in order to achieve rapid development and dissemination of biodiversity conservation and management technologies, farmers must be empowered fully to train other farmers using their successful models, while researchers must work to improve existing farmer interventions (contribution from Fidelis Kaihura, Tanzania Coordinator, People, Land Management and Environmental Change (PLEC)).
Raised awareness and increased sharing of information and knowledge are necessary to strengthen farmers’ capability for the biological management of soil ecosystems. In particular, such knowledge should help them make decisions and evaluate the effects of their land management practices in regard to the effective use of soil life and sustainable management.
(P.S. Ramakrishnan, Jawaharlal Nehru University, India)
A range of case studies illustrated the needs for capacity building for agricultural education through farmer-centred training programmes that include soil ecology and soil biological management. Examples of capacity building included: a farmer-centred natural resources management approach in Latin America; a global below-ground biodiversity research and networking project; an organic resources database to guide the selection and management of organic inputs; the piloting of farmer field school (FFS) approaches for soil productivity improvement in Africa, and a regional network for promoting conservation agriculture in Africa.
Drawing on experience in Ecuador, it was noted that soil biological considerations are not considered in the agricultural education process and that soil microbiology and agro-ecology should be integrated into university curricula. There is also a need to bring about a policy change in order to promote more integrated agricultural approaches and to lobby governments that fertilizers are not the solution for sustaining yields. Workshop participants agreed that these are widespread problems. CAMAREN, a consortium for natural resources management training and capacity building processes in Ecuador, uses a step-by-step methodology. The process starts with a week of fieldwork for problem diagnosis, sharing experiences and visits in the field, and interaction with farmers to learn of indigenous knowledge and practices. This is followed by the development of a theoretical framework through group work and interaction in the classroom and, finally, practical work and capacity building throughout the season. This methodology, based on a farmer-centred approach, has contributed effectively to the development of sustainable agricultural practices in several regions in Ecuador. There is an opportunity to improve the work of CAMAREN by enhancing training on biological management of soil fertility, e.g. through training trainers on soil ecology, exchange of expertise, improving regional and national collaboration, etc.
(Gustavo Bernal, National Institute of Agricultural Research, and Rusvel Rios, CAMAREN)
The Below-ground Biodiversity (BGBD) project is an important contribution to assessment and adaptive management. It has recently been launched in Brazil, Mexico, Côte d’Ivoire, Uganda, Kenya, India and Indonesia. The objective is to enhance awareness, knowledge and understanding of below-ground biological diversity, important to sustainable agricultural production in tropical landscapes, by the demonstration of methods for conservation and sustainable management. The project will explore the hypothesis that, by appropriate management of above- and below- ground biota, optimal conservation of biodiversity for national and global benefits can be achieved in mosaics of land uses at differing intensities of management with simultaneous gains in sustainable agricultural production. The expected project outcomes are:
internationally accepted standard methods for the characterization and evaluation of BGBD, including a set of indicators for BGBD loss;
inventory and evaluation of BGBD in benchmark sites representing a range of globally significant ecosystems and land uses;
a global information exchange network for BGBD;
sustainable and replicable management practices for BGBD conservation identified and implemented in pilot demonstration sites in representative tropical forest landscapes in seven countries;
recommendations on alternative land use practices, and an advisory support system for policies that will enhance the conservation of BGBD;
improved capacity of all relevant institutions and stakeholders to implement conservation and management of BGBD in a sustainable and efficient manner.
The BGBD project strategy recognizes that soil biota require selective study because there is no single method for studying soil biodiversity and it is not possible to study simultaneously all functional groups: macrofauna/ecosystem engineers, e.g. termites and earthworms; microregulators, e.g. nematodes; microsymbionts, e.g. mycorrhiza, rhizobia; soil-borne pests and diseases, e.g. fungi, invertebrates; C and nutrient transformers, e.g. methanogens, nitrifiers; and decomposers, e.g. cellulose degraders. Benchmark sites will be established to represent a gradient of land use intensification. The forest system will be taken as a baseline for the inventory and BGBD evaluation, using site selection criteria and site characterization and participatory assessment processes.
The BGBD partnership project provides an important basis for coordinating further research work in developing countries with a view to its practical application for agricultural development. It will address the two main pathways of soil biological management: (i) direct biological control by inoculation, or genetic manipulation; and (ii) indirect ecological control by manipulation of the cropping system, the plant, organic matter and the environment. A range of soil biotechnologies will be considered, including the use of: Rhizobium for N2 fixation, mycorrhiza for nutrient uptake, biological control for plant health, rhizobacteria for plant growth, decomposers for nutrient use, and macrofauna for soil structure. Cropping system designs favouring BGBD will be identified, including the link between diversity above- and below-ground and emphasizing the central role of soil organic matter. A range of optional management practices for soil conservation and enhancement of soil organic matter and soil biodiversity will be assessed such as: intercropping, legume cover crops, agroforestry, conservation tillage, livestock linkages and farmyard manure. Soil-based ecosystem services will also be addressed, including: nutrient cycles; gas exchange and climate regulation; hydrological flows and water supply; and biological control of pests.
(George Brown, on behalf of Mike Swift, TSBF Coordinator, in coordination with Fátima Guimarães, BGBD Project Brazil)
This database, prepared by the TSBF and the University of Wye, the United Kingdom, is available through a Web site and on diskette. This database was recognized as a valuable tool. It comprises over 250 different organic materials characterized by a range of standard methods and parameters: N, P, potassium (K), Ca, lignin, polyphenols; soil and climate; decomposition and digestibility. It illustrates how N-release patterns and fertilizer equivalency values, and thus crop responses, are determined by organic resource type and quality as well as by climate and soil biodiversity. Guidelines are available for the selection and management of organic inputs through direct incorporation, mixing with fertilizers and other materials, or surface application (http://www.wye.ac.uk/sme/projects/soil/ord2.htm).
The FFS process was developed for IPM in Asia, replicated successfully across many regions and expanded to include production considerations. FAO is adapting the FFS process with partners in Uganda, Tanzania and Zimbabwe to promote farmer experimentation on techniques and options for soil productivity improvement (Plate 2). A curriculum and training materials are being developed for soil productivity improvement (SPI) and the approach is being piloted through training of trainers (farmers and extensionists) and adapted to local farming systems and contexts. Involvement of national agricultural research, extension, university and a range of projects is expected to lead to its wider adoption and adaptation to other farming systems. The TSBF is a partner and the Rockefeller Foundation is providing funding support. The farmer-driven approach is based on participatory diagnosis of constraints and opportunities and adapted training curricula. It is expected to facilitate rapid expansion by building on experiences. Conservation agriculture approaches including no-till, cover crops and crop rotations are being introduced among the various options for soil productivity improvement. This is expected to include a focus on soil biological management when training materials become available. A joint workshop for partners (February/March 2003) is intended to build on lessons learned in the development of a wider programme for sub-Saharan Africa (http://www.fao.org/landandwater/agll/farmspi/).
(Sally Bunning, Land and Water Development Division, FAO)
Plate 2. Extensionists participating in a farmer field school - soil productivity improvement (FFS-SPI) process in East Africa - [S. Bunning]
The African Conservation Tillage (ACT) network facilitates information exchange and the sharing of experiences of the introduction of conservation agriculture approaches, including expertise, equipment and tools adaptation, soil management and cropping systems and cover crop selection and adaptation (www.fao.org/act-network or e-mail: [email protected]). The ACT is supported by FAO, the German Technical Cooperation Organization (GTZ) and other partners. It also benefits from experiences in other regions, for example, through South-South cooperation with experts from Brazil. In order to facilitate a multistakeholder process, several workshops have been organized: mechanization (Jinja, Uganda 2002), and training at extension and technical levels (Harare, 2000 and Zambia, 2002).
Ademir Calegari emphasized that the success behind no-tillage in Brazil was the wise selection of cover crops including properties to suppress diseases. In Africa, as farmers need to produce food and cash crops, it may be difficult to convince farmers of the need for cover crops. One can start with crop residues as surface mulch while researching solutions that demonstrate clear economic, social and environmental benefits. This illustrates the importance of research-farmer interaction as well as an enabling environment (germplasm, seeds, tools, etc.).
These cases illustrated the importance of using existing tools and methods and of ensuring participatory approaches for introducing soil biological management as a means of addressing low and declining productivity and soil degradation. Through close collaboration with the seven country teams, the TSBF BGBD Network project will provide an important base of research and expertise for further development of the Soil Biodiversity Initiative (SBI). The results from this project could be disseminated and built on in other countries through effective collaboration and partnerships.
(Richard Fowler)
This theme was covered by four presentations on: innovative methods for monitoring soil biological activity and pest-pathogen interactions; the link between soil biological activity, sustainable land use systems and C sequestration; the proposed research programme of the Consultative Group for International Agricultural Research (CGIAR) system for the promotion of BNF; and soil and water conservation in the Sahel through enhanced biomass production.
The challenges involved in the measurement and manipulation of soil biodiversity are considerable, but measurement is essential to managing manipulation. For some groups of organisms, functional characterization, such as determination of trophic groups of nematodes, provides good basic information on their diversity without identification of individual specimens. For microbial taxa, modern molecular tools show considerable promise in the measurement and characterization of soil biodiversity. Techniques that are well established for bacteria, such as differential gradient gel electrophoresis (DGGE) of DNA profiles extracted from soil, are starting to be used for fungi and have potential for diversity measurement in other important organism groups as well. Molecular methods can also detect particular species such as pathogens, and are potentially much more reliable than traditional baiting or isolation techniques. Modern and traditional tools can combine to give a more complete picture of soil biodiversity. These techniques can help measure differences in soil biodiversity following perturbations or changes in management practices, and help understand the relationship between pest or pathogen levels and saprobic competitors. There is evidence that agricultural practices that promote saprobic fungal diversity and biomass also lead to a reduction in pest and pathogen problems, especially in the seedling establishment stage. There is great potential for the addition of biotic supplements to sown seed to aid establishment, and to use fungal antagonists such as Trichoderma species to protect vulnerable plants.
(Paul Cannon, CAB International [CABI])
Climate change predictions suggest a temperature rise of 2-4 percent and changes in rainfall. What are the implications on soil carbon stocks and dynamics? Dr Lal illustrated the important impact of soil aggregation by earthworms on soil organic C and the close relationship between soil biodiversity and C sequestration (Plate 3). Hence, there is a need to enhance soil biological activity through improved management practices. Agriculture manipulates soil C through uptake (CU), fixation (CF), emissions (CE), and transfer (CT), where CU + CF = CE + CT. When decomposed, organic residues provide CO2 (60-80 percent) and complex humic compounds (10-30 percent) which are more stable at depth (a 0.1-percent change in soil organic C is equivalent to 1 ppm atmospheric C). A no-till system can optimize soil organic C through the return of crop residues to the soil, cover crops and precise use of external inputs and water. There are hidden C costs in conventional tillage through residue removal, erosion from bare fallow or poor crop cover, emissions in fertilizer manufacture (0.86 kg C/kg N fertilizer), and pesticides. Carbon sequestration requires more sustainable agriculture and land use systems including conservation agriculture approaches, grazing land management and erosion control. This is so that soil degradation trends are reversed, soil quality and resilience improved, biomass production increased, and the rate of enrichment of atmospheric concentration of greenhouse gases decreased.
(Rattan Lal, University of Ohio, The United States of America)
PLATE 3. Gallery of an anecic earthworm from the Colombian “Llanos” filled with casts, the upper part having been split by a smaller endogeic earthworm species. Root development is enhanced and the implications of this process in C sequestration warrant further consideration - [P. Lavelle]
This research programme was proposed in 2002 on the basis of a stakeholder workshop (Montpellier, 2001) (http://www.icrisat.org/bnf/Reports.htm). It was expected to involve several CGIAR centres, international agricultural research centres (IARCs), NGOs, national agricultural research organization (NARs), and international BNF networks in the development of global strategies for the promotion of BNF technologies and the enhancement of soil fertility, focusing on the most vulnerable agro-ecosystems. One of its objectives is to enhance and sustain soil fertility through the development and adoption of integrated nutrient management practices and appropriate BNF technologies. The research programme would develop holistic strategies that combine appropriate technologies and policy options aimed at narrowing the soil fertility gap with a better understanding of the main biophysical and socio-economic factors and constraints. It was expected to foster scientific and technological cooperation between developing countries and leading research institutions, which are developing most of the innovative technologies. The development and adoption of new options of sustainable soil fertility management would also result in increased crop productivity and would help the resource farmers of developing countries to improve their livelihood. Although the programme was not retained as a CGIAR priority, a number of research bodies and CGIAR centres in collaboration with FAO are still soliciting funding support to promote BNF in Central and South America and East and West Africa.
(Rachid Serraj, ICRISAT)
Mention was made of the approach of a soil and water conservation research project in the Central Plateau, Burkina Faso, supported by the International Fund for Agricultural Development (IFAD) with several partners. It focuses on enhancing biomass through the use of local species, water harvesting with stone bunds, and raising awareness of the need to regenerate the primary production process.
(Abdoulaye Mando, Institut pour l’Environnement et la Recherche Agricole [INERA])
These capacity-building case studies illustrated two important points. First, the development of research and training capacities to jointly address critical economic, social and environmental issues is essential for the transition to sustainable development. Such integrated scientific and training capacities can help countries better understand their current situation and devise effective responses to meet future challenges. Scientific research may be global in scope but its applications work best when tailored to national and subnational settings. Second, coordinated efforts through the strengthening of South-South and North-South institutional partnerships would help foster the mobility of scientists and technologists as part of a larger strategy for promoting the exchange of knowledge and experiences to advance the transition towards sustainable development.
One aspect that was not well highlighted in the Londrina case studies was the use of improved understanding of soil biodiversity and soil ecosystem functioning for influencing policy. A good example is provided by BIODEPTH, a pan-European experiment investigating the impacts of biodiversity on ecosystem function in model grassland systems. It has yielded powerful data and results supporting the importance of biodiversity for providing ecosystem energy flow with implications for European environmental policy on grasslands management. Small meadow plots were created by exterminating existing plants and seed bank and then sowing wildflower and grass seeds (constant seed rate) in different species mixtures. The highest diversity of sowing was based on local species richness, with five levels of diversity reducing richness down to single species monocultures. This mimicked the gradual extinction of plant species from grasslands. Energy flow was monitored by measuring ecosystem processes, such as plant growth (above-ground and rooting) and harvest yield (productivity); breakdown of dead leaves (decomposition); and nutrient amounts in plants and soils (recycling and retention). After the establishment year, over the first two years of the experiment, a clear relationship was found between reduced ecosystem function and reduced species diversity for a wide range of ecosystem processes (across all eight field sites with different climate, soil and plant types). Table 1 shows the initial analysis of this research.
Table 1. Initial results of BIODEPTH research on the effects of biodiversity loss on ecosystem function in model grassland systems
|
Ecosystem process response to declining biodiversity |
Environmental implications and policy relevance |
|
Plant productivity |
Agricultural sustainability |
|
Decrease in above-ground biomass production, plant canopy architecture and below-ground root production |
Reduced harvest yields of low-input agriculture Implications on sustainable nutrient and water use |
|
Nutrient dynamics |
Ecosystem sustainability |
|
Decrease in N retention in plant biomass and soil nutrients Increase in soil nitrate leaching and varied affect on soil moisture |
Reduced agricultural productivity and N sequestering Reduced groundwater quality and reduced drought resistance and reduction of runoff |
|
Decomposition processes |
Ecosystem sustainability |
|
Not clear response of plant litter, cellulose, cotton methods |
Longer term studies necessary |
|
Plant community dynamics |
Agricultural sustainability |
|
Increase in community invasibility by weeds and in plant parasites and fungal pathogens |
Reduced resistance to weed/alien invasion and to crop pests |
|
Soil microbial dynamics |
Global change |
|
Decrease in soil respiration, soil microbial biomass, bacterial functional diversity/activity and mycorrhizae (root fungi) |
Reduced C sequestering and energy flow, reduced plant-soil interactions and N sequestering |
|
Invertebrate communities |
Biodiversity conservation and resilience |
|
No clear response to above- and below-ground invertebrate diversity Varied response to abundance of different invertebrate groups and to above-ground herbivore damage |
Possible relationship with nutrient cycling and food web dynamics |
Source: Extracted from: http://www.cpb.bio.ic.ac.uk/BIODEPTH/.
){kind=link}