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The potential use was investigated of mycorrhizal and rhizobial native plants for the enhanced reclamation of disturbed mine and natural sites at the Essakane mine in Burkina Faso. Soil core samples were collected from six sites, two disturbed sites, tailings and waste rock, three non-disturbed sites, including two sites reclaimed in 2009, and a natural site outside the mine. All the materials showed an absence of ectomycorrhizal fungi and very low presence of rhizobia and arbuscular mycorrhizal fungi. The two disturbed sites showed lower spore density and root colonisation rate for arbuscular mycorrhizal fungi than the non-disturbed sites, attributed to the high alkalinity and low carbon content of these soils. A greenhouse experiment was carried out to test different symbiotic inocula and substrates on Acacia senegal seedlings. The inocula were the rhizobium strain ORS 3588 from Senegal and two strains of arbuscular mycorrhizal fungi, Glomus aggregatum from Senegal and Glomus irregulare, a commercial product from Canada, and the substrates contained manure and sand in amounts of 50:50, 25:75 and 0:100. After 75 days the dry mass was significantly higher on substrates with manure. Inoculation had no effect except for the shoot dry mass on the substrate without manure. In the 100% sand substrate the shoot dry mass of plants inoculated with Glomus aggregatum was significantly higher than for plants inoculated with Glomus irregulare, rhizobium or without inoculation., The potential use was investigated of mycorrhizal and rhizobial native plants for the enhanced reclamation of disturbed mine and natural sites at the Essakane mine in Burkina Faso. Soil core samples were collected from six sites, two disturbed sites, tailings and waste rock, three non-disturbed sites, including two sites reclaimed in 2009, and a natural site outside the mine. All the materials showed an absence of ectomycorrhizal fungi and very low presence of rhizobia and arbuscular mycorrhizal fungi. The two disturbed sites showed lower spore density and root colonisation rate for arbuscular mycorrhizal fungi than the non-disturbed sites, attributed to the high alkalinity and low carbon content of these soils. A greenhouse experiment was carried out to test different symbiotic inocula and substrates on Acacia senegal seedlings. The inocula were the rhizobium strain ORS 3588 from Senegal and two strains of arbuscular mycorrhizal fungi, Glomus aggregatum from Senegal and Glomus irregulare, a commercial product from Canada, and the substrates contained manure and sand in amounts of 50:50, 25:75 and 0:100. After 75 days the dry mass was significantly higher on substrates with manure. Inoculation had no effect except for the shoot dry mass on the substrate without manure. In the 100% sand substrate the shoot dry mass of plants inoculated with Glomus aggregatum was significantly higher than for plants inoculated with Glomus irregulare, rhizobium or without inoculation.

Five exotic tree species (Acacia angustissima (Mil.) Kuntze, Acacia mangium Wild, Gliricidia sepium (Jacq.) Alp., Leucaena hybrid (LxL), and Leucaena leucocephala (Lam.) de Wit) were investigated to determine whether parameters of nursery seedling stock quality could be used to predict their field performance in a plantation irrigated with treated waste-water to produce fodder and wood. Plants were grown in the nursery in two contrasting rooting substrates (ordinary nursery soil and sand), predicted to have different effects on resource allocation. Three categories of morphological indicators were measured, i.e. plant dimensions (height, diameter, root length), plant weights (shoot, root and whole plant weights) and indices (sturdiness quotient ‘SQ’, shoot:root dry weight ratio ‘SRR’ and Dickson’s quality index ‘DQI’). In the nursery, all species performed better in the ordinary nursery soil for all growth parameters except root length. Thus ordinary nursery substrate appeared superior to sand in terms of plant quality. However, a follow up at plantation phase revealed that only some morphological attributes or ratios were suitable to predict field performance for the five tested species in irrigated plantation. In addition, the effect of the substrate observed at the nursery stage had disappeared 12 months after out planting due to the availability of water and nutrients provided by the treated waste water used for the irrigation. The results showed that root collar diameter and DQI appeared to be the most appropriate indicators to predict the outplanting performance of the five tested species in a short-rotation irrigated plantation in semi-arid Burkina Faso. The former measure is simpler and non-destructive.

Five exotic tree species (Acacia angustissima (Mil.) Kuntze, Acacia mangium Wild, Gliricidia sepium (Jacq.) Alp., Leucaena hybrid (LxL), and Leucaena leucocephala (Lam.) de Wit) were investigated to determine whether parameters of nursery seedling stock quality could be used to predict their field performance in a plantation irrigated with treated waste-water to produce fodder and wood. Plants were grown in the nursery in two contrasting rooting substrates (ordinary nursery soil and sand), predicted to have different effects on resource allocation. Three categories of morphological indicators were measured, i.e. plant dimensions (height, diameter, root length), plant weights (shoot, root and whole plant weights) and indices (sturdiness quotient ‘SQ’, shoot:root dry weight ratio ‘SRR’ and Dickson’s quality index ‘DQI’). In the nursery, all species performed better in the ordinary nursery soil for all growth parameters except root length. Thus ordinary nursery substrate appeared superior to sand in terms of plant quality. However, a follow up at plantation phase revealed that only some morphological attributes or ratios were suitable to predict field performance for the five tested species in irrigated plantation. In addition, the effect of the substrate observed at the nursery stage had disappeared 12 months after out planting due to the availability of water and nutrients provided by the treated waste water used for the irrigation. The results showed that root collar diameter and DQI appeared to be the most appropriate indicators to predict the outplanting performance of the five tested species in a short-rotation irrigated plantation in semi-arid Burkina Faso. The former measure is simpler and non-destructive.

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

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 hig

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

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 hig

Les zones sud et ouest du Burkina Faso bénéficient de conditions pluviométriques soudaniennes, plus favorables à l'agriculture. Des agriculteurs migrants, venus du centre et du nord du plateau Burkina surpeuplé, s'installent sur les fronts pionniers. Pour étudier, en milieu réel paysan, les risques de dégradation du potentiel de production des sols de cette région d'accueil, on a choisi une vingtaine de parcelles. La dégradation constatée est rapide. Elle se manifeste d'abord par une chute selon une fonction de type puissance (liée au temps de mise en culture) du taux de matières organiques de l'horizon superficiel. Il en résulte une baisse tout à fait similaire de la disponibilité des nutriments (particulièrement de l'azote) et des taux d'infiltration. Au bout de 5 à 10 ans de culture, le sol n'est plus à même d'assurer l'alimentation minérale et hydrique de la principale culture vivrière (le sorgho) et les rendements s'effondrent. La reconstitution du stock de matières organiques du sol ainsi que la mise en pratique de techniques culturales susceptibles d'améliorer sensiblement l'infiltration s'imposent donc sous peine de voir les paysans contraints à conquérir de nouvelles terres, actuellement en voie de raréfaction

Les zones sud et ouest du Burkina Faso bénéficient de conditions pluviométriques soudaniennes, plus favorables à l'agriculture. Des agriculteurs migrants, venus du centre et du nord du plateau Burkina surpeuplé, s'installent sur les fronts pionniers. Pour étudier, en milieu réel paysan, les risques de dégradation du potentiel de production des sols de cette région d'accueil, on a choisi une vingtaine de parcelles. La dégradation constatée est rapide. Elle se manifeste d'abord par une chute selon une fonction de type puissance (liée au temps de mise en culture) du taux de matières organiques de l'horizon superficiel. Il en résulte une baisse tout à fait similaire de la disponibilité des nutriments (particulièrement de l'azote) et des taux d'infiltration. Au bout de 5 à 10 ans de culture, le sol n'est plus à même d'assurer l'alimentation minérale et hydrique de la principale culture vivrière (le sorgho) et les rendements s'effondrent. La reconstitution du stock de matières organiques du sol ainsi que la mise en pratique de techniques culturales susceptibles d'améliorer sensiblement l'infiltration s'imposent donc sous peine de voir les paysans contraints à conquérir de nouvelles terres, actuellement en voie de raréfaction