Utilisation of wastewater for fuel and fodder production and environmental and social benefits in semi-arid, peri-urban zones of sub-Saharan Africa. Final Report 1/12/2002 - 30/11/2007 Contract number ICA4-CT-2002-10017

The overall objective was to develop low-tech water treatment and irrigation systems and test their use for the production of fuel wood and fodder in semi-arid sub-Saharan Africa. Sites for waste water treatment plants and irrigation systems were identified and the systems were constructed in Burkina Faso, Mali and Niger. Project partners were trained in how to use and maintain the systems. The irrigation sites were characterised in advance of tree planting, and soil and water analyses are being conducted regularly. Tree species with potential for use in irrigated conditions in each country were identified and experimental designs for the trials produced. Some species were used in common in all three countries. Nursery screening trials were conducted and plants were then planted at the irrigation sites. Trees grew quickly under the irrigated conditions and many species performed well. Species which were selected for their good performance in the nursery were not necessarily the best performers in the field. Biomass production was determined and the effects of different coppicing treatments on regrowth were assessed. Parameters of planting stock quality were assessed and incidence of pest attacks determined. Partners were also trained in the use of sap flow and associated equipment. Considerable variation between tree species in water use was noted, together with differential effects according to the inoculation history of the plants. Working in controlled glasshouse conditions, using sterilised soil media, considerable variation in effectiveness of different mycorrhizal strains on different tree species was detected. When plant response to simulated irrigation water was measured, uninoculated plants grew very poorly irrespective of whether they are receiving the simulated irrigation water or not. Thus mycorrhizal infection enabled plants to make use of the nutrients in the irrigation water. Initially, nursery and field studies gave much less clear results. However, assessments during the final year of the project demonstrated positive effects of inoculation on tree growth in Mali and Niger. These observations were reinforced on the rhizobial side by molecular studies, using strain-specific probes for nodule analysis. In Ouagadougou it was estimated that 225,004 tons of fuel wood and 6708 tons of charcoal per year are transported to the city. The average price of firewood was approximately 21 F CFA per kg, and charcoal was 60 – 110 F CFA per kg. Sellers can achieve a substantial income from sales. The large quantities of fuel imported into Ouagadougou highlight the pressure on fuel resources. This is further indicated by the observations in Niger and Mali. Dissemination to stakeholders has been conducted and is continuing. The irrigation sites are continuing to be run. An important development is the formation of a partnership with representative farmers’ organizations regrouped under the umbrella of ROPPA (Réseau des Organisations Paysannes et des Producteurs Agricoles d’Afrique de l’Ouest, who federates millions of farmers through twelve west African countries, with the objective of bringing symbionts to farmers

Utilisation of wastewater for fuel and fodder production and environmental and social benefits in semi-arid, peri-urban zones of sub-Saharan Africa. Fifth Annual Report: 1/12/2006 – 30/11/2007

Summary Report Since the beginning of the contract, the results achieved are as follows: Work package 1 Water treatment and irrigation Sites for waste water treatment plants and irrigation systems were identified and the systems have been constructed in Burkina Faso, Mali and Niger. Progress was slower than planned for a variety of reasons, including delays to obtaining permits for construction, delays associated with importation and shipping of components and delays in purchase of expensive items due to cash flow problems. Staff have been trained in how to use and maintain the systems. Some modifications and refinements and repairs have been necessary, but systems are functioning in each country. The irrigation sites were characterised in advance of tree planting, and soil and water analyses are being conducted regularly. Work package 2 Tree growth and management Tree species with potential for use in irrigated conditions in each country were identified and experimental designs for these trials were produced. Some species are being used in common in all three countries. Nursery screening trials were conducted and plants were then out planted to the irrigation sites. Trees have grown quickly under the irrigated conditions and many species are performing well. Few problems have been detected. Species which were selected for their performance in the nursery are not necessarily the best performers in the field plots. In this year, biomass production has been determined and the effects of coppicing at 2 different heights on regrowth have been assessed. Work package 3 Tree water use and soil water status Staff in all three countries with irrigation systems have received training in the use of sap flow, soil water and associated measuring equipment. In Mali, considerable variation between tree species in soil water use has been noted, together with differential effects according to the inoculation history of the plants. Acacia angustissima appears to have particularly high water use and is easily water-stressed, whereas A. mangium appears to be more robust in its performance. Even with irrigation, tree water use is declining by the late morning, indicating stomatal closure. In Burkina Faso, L. hybrid showed the highest transpiration rate (1.09 L cm-2 day-1), followed by L. leucocephala (0.93 L cm-2 day-1), G. sepium (0.93 L cm-2 day-1) and A. angustissima (0.61 L cm-2 day-1). Gliricidia did not show morning stomatal closure, whereas Acacia and the Leucaenas did. Stomatal closure was especially marked with Acacia angustissima, confirming the results previously obtained in Mali. The long term use of physiological equipment under tropical conditions has proved difficult as the equipment is not particularly robust. Work package 4 Microsymbionts and N fixation Working in controlled glasshouse conditions, using sterilised soil media, the UK partner has identified considerable variation in effectiveness of different mycorrhizal strains on different tree species. After the initial screening phase, selected tree species were taken on to the second phase of the study in which plant response to simulated irrigation water is being measured. Uninoculated plants grew very poorly irrespective of whether they are receiving the simulated irrigation water or not. The response of inoculated plants to irrigation varied with inoculant and tree species. Initially, nursery and field studies in Mali, Niger and Burkina Faso gave much less clear results. However, assessments during this final year of the project have demonstrated positive effects of inoculation on tree growth in Mali and Niger. These observations are reinforced by molecular studies, using strain-specific probes for nodule analysis, which have been successfully tested against the inoculants, studies on samples collected from the field experiments in Mali suggest that the inoculant strains are absent – other types are present. This suggests that either the original inoculation was unsuccessful, or that the inoculants have been out-competed by indigenous strains. Work package 5 Economics and quality of produce Questionnaires have been developed by the partner in Niger, in collaboration with other partners. All countries have now completed their surveys, which have generated a considerable amount of useful information about fuel wood and fodder supplies. For Ouagadougou (population 960000 in 2000), it is estimated that 225,004 tons of fuel wood and 6708 tons of charcoal per year are transported to the city. The average price of firewood was approximately 21 F CFA per kg, and charcoal was 60 – 110 F CFA per kg. Sellers can achieve a substantial income from sales. The large quantities of fuel imported into Ouagadougou highlight the pressure on fuel resources. This is further indicated by the observations in Niger, where wood cutters cut an average of 27 steres per month, and each village can have 40 – 80 woodcutters. In Mali, annual wood fuel consumption averages about 0.5 ton per capita, and collection of a cart load of wood can involve a journey of 30 km and 3 days. Increasing numbers of grazing cattle are creating conflicts between different land uses. Assessments of fuel wood quality and palatability to animals have been made in Mali. Work package 6 Soil and plant nutrition Nutrient contents of irrigation water and soil nutrient status are being monitored at each site. In Mali, studies showed that pesticide levels were not significant, but that there was sometimes a build up of ammonium and turbidity in water flowing out of the plantation. In Burkina Faso microbiological analyses showed that the water treatment was successful in reducing levels of bacteria. Analyses have continued in all countries and no problems have been detected. Work package 7 Planting stock quality Studies have been conducted in Burkina Faso and Mali. Using various parameters of planting stock quality (shoot: root ratio, sturdiness quotient, Dickson’s Quality Index), considerable variations in quality have been identified, between species, production methods and between partners testing the same species. In Burkina Faso, a previous pot experiment was planted out. Previous effects of inoculation, substrate and pot size were no longer evident, however there was considerable variation between species in growth. At the time of planting, there were considerable differences in shoot: root ratios between species. Work package 8 Pest monitoring and management Studies in Mali have highlighted attack by termites on Leucaena and Calliandra, causing death of experimental trees, and the susceptibility of Acacia angustissima to prolonged flooding

Ectomycorrhizal diversity enhances growth and nitrogen fixation of Acacia mangium seedlings

Increasing interest has been given so far to the role of mycorrhizal symbiosis on plant diversity and ecosystem productivity. However much remains unknown about the effect of ectomycorrhizal fungal diversity on plant growth and rhizobial symbiosis. The purpose of this study is to investigate the influence of ectomycorrhizal diversity on root nodulation and plant nutrient uptake during plant growth. A gradient of ectomycorrhizal diversity was created (ranged from one to six fungal isolates) on Australian Acacia (Acacia mangium) seedlings grown on a phosphate-deficient soil in controlled conditions. The results dearly show (i) an enhancement of A. mangium growth due to ectomycorrhizal fungal inoculation, (ii) as well as significant effects of increasing ectomycorhizal diversity and soil ectomycorrhizal mycelium density on whole plant biomass and plant nutrient uptake. They also reveal an effect of ectomycorrhizal diversity effect on the functioning of the nitrogen-fixing symbiosis. These results emphasize the need to manage soil ectomycorrhizal potential (abundance and diversity of ectomycorrhizal mycelium) in forest management practices in order to optimize N-2 fixation and seedling growth, leading thus to dramatic improvements in outplanting performances with fast-growing tree legumes on various reafforestation sites, more particularly in tropical and Mediterranean areas