Effet des touffes de Guiera senegalensis (J.F. Gmel) sur la fertilité des sols dans la région de maradi (Niger)

Objectifs : A Guidan Bakoye, dans la région de Maradi au Niger, pour faire face à la dégradation et la baisse de la fertilité des terres, les paysans ont entre autres adopté la régénération naturelle assistée des espèces ligneuses telles que Guiera  (Guiera du Sénégal). Cette étude traite de l’influence des touffes de cet arbuste sur la fertilité des sols dans le terroir de Guidan Bakoye.Méthodologies et résultats : Un dispositif en blocs randomisés complet avec trois répétitions des touffes, a été utilisé en plein champ. Des prélèvements des sols ont été effectués autour des touffes selon les points cardinaux, les distances 0, 50, 100, 150 et 200 cm de la touffe et la profondeur du sol (0 -10 ; 10 -20, 20 - 30 et 30 -40 cm), et leurs caractéristiques physico-chimiques ont été déterminées. Les résultats obtenus ont révélé généralement une amélioration significative des paramètres physico-chimiques des sols localisés à proximité des touffes de Guiera senegalensis.Conclusion et application de la recherche : Il ressort de cette étude, un fort taux de repeuplement de Guiera senegalensis (1800 pieds/ha) dans le terroir grâce à la régénération naturelle assistée et à l’introduction de la technique de marcottage. Par ailleurs, les résultats des analyses physico-chimiques des sols sous Guiera senegalensis, ont montré l’absence de changement textural avec la distance, et la prédominance des sables dans les horizons de surface indiquant que les touffes de Guiera senegalensis piègent essentiellement les sables transportés par les vents. Il est aussi apparu que les touffes de Guiera senegalensis ne semblent pas influencer le pH, la capacité d’échanges cationiques et le Ca contrairement à la matière organique, au phosphore, Mg et K. En définitive, les touffes de Guiera senegalensis améliorent moyennement les propriétés physico-chimiques du sol.Mots clés : Touffes, Guiera senegalensis, paramètres physico-chimiques des sols, Guidan Bakoye, MaradiEffect of Guiera senegalensis (JF Gmel) tufts on soil fertility in Maradi (Niger)ABSTRACTObjectives: In arid and semi-arid, the degradation and the decline in the fertility of land is a major concern for farmers. At Guidan Bakoye, in the Maradi region, to cope with this, the farmers have adopted the assisted natural regeneration to rebuild a degraded environment due to uncontrolled use. Thus, woody species like Guiera senegalensis (Guiera du Sénégal) have been bred and maintained in this region. The present study deals with the influence of the tufts of this plant on the soil fertility of Guidan Bakoye.Methodology and Results: A device block randomized complete with three repetitions of the tufts, was used in the field. Soil Samples were carried out around the tufts according to the cardinal points, the distances of 0, 50, 100, 150 and 200 cm of the tuft and the soil depth (0 -10 ; 10 -20, 20 -30 and 30 -40 cm).Conclusion and application of research: This study show a high rate of Guiera senegalensis repopulation (1800 plants/ha) in the soil through assisted natural regeneration and the introduction of the technique of layering. In addition, the results of the physico-chemical analysis of soils under Guiera senegalensis have shown the absence of textural change with the distance, and the predominance of sand in the surface horizons, indicating that the tufts of Guiera senegalensis trap essentially the sand transported by the wind. It is also apparent that the tufts of Guiera senegalensis did not seem to influence the pH, the capacity of the cation exchange and the Ca in contrast to the organic matter, phosphorus, Mg and K. In the end, the tufts of Guiera senegalensis improve moderately physico-chemical properties of the soil.Keywords : Tufts, Guiera senegalensis, physico-chemical parameters of the soil, Guidan Bakoye, Marad

Monitoring of Urban Growth and its Related Environmental Impacts: Niamey Case Study (Niger)

AbstractThe present contribution is about a preliminary study of the evolution of Niamey city (Niger) during last decades.Recent advances in remote sensing, both in satellite hardware technology and image availability development, provide opportunities image collection and multitemporal analysis on urban form and size that can be useful for policy and planning. Some opportunities for, and limitations on, monitoring urban growth using remote sensing data are shown in the present contribution; moreover examples of environmental impacts of urban growth, as monitored with remote sensing, are provided in order to define future development of dumps and quarries and its environmental impacts on Niamey city

Effet des touffes de Hyphaene thebaica (Mart) sur la production du mil dans la région de Maradi (Niger)

La région de Maradi est confrontée à la saturation de l’espace et à la baisse généralisée de la fertilité des sols. Pour faire face à cette situation, les paysans ont adopté l’association céréales – légumineuses, l’apport des fertilisants par micro doses et l’utilisation des ligneux dans les champs. Ainsi, dans le terroir de El Guéza, les céréales sont cultivées en association avec l’arbuste Hyphaene thebaica, très répandu dans la localité. C’est dans cette optique que cette étude a été conduite pour évaluer l’influence des touffes de Hyphaene thebaica sur la production du mil dans ce terroir. Ainsi, des essais de culture du mil ont été menés selon un dispositif en blocs randomisés complet sur 3 parcelles avec touffes de Hyphaene thebaica et une parcelle témoin (sans touffes). Les résultats obtenus ont révélé qu’autour de la touffe de Hyphaene thebaica, le mil présente un enracinement très dense et bien développé alors qu’hors Hyphaene thebaica, il a des racines fines, moins denses et développées latéralement. Par ailleurs, les rendements en grains et en paille autour de Hyphaene thebaica sont respectivement de 1300 à 1820 kg/ha et 4630 à 6740 kg/ha alors qu’ils sont de 440 kg/ha et 2000 kg/ha pour le témoin. Cette étude montre clairement que les touffes de Hyphaene thebaica améliorent la production du mil.© 2015 International Formulae Group. All rights reserved.Mots clés: Touffes, Hyphaene thebaica, mil, rendements, El Guéza, MaradiEnglish Title:  Effect of Hyphaene thebaica (Mart) tufts on the millet production in Maradi region (Niger)English AbstractThe region Maradi is facing the land saturation and the general decline of soil fertility. To cope, farmers have adopted several techniques like “association cereals – legumes”, input of micro-doses fertilizers and the use of woody species in the fields. Thus, in the land of El Guéza, cereal crops grains are grown in combination with Hyphaene thebaica shrub, widespread in this locality. It is in this light that this study was conducted to evaluate the influence of Hyphaene thebaica tufts on millet production in this region. Thus, millet cultivation trials were conducted according to a randomized complete block design of 3 plots with Hyphaene thebaica tufts and a control plot (without tufts). The results obtained revealed that around the tufts of Hyphaene thebaica, millet has a very dense root and well developed whereas outside Hyphaene thebaica, millet has fine roots, less denses and developed laterally. Moreover, the yields of grain and straw around Hyphaene thebaica are 1300-1820 kg / ha from 4630 to 6740 kg / ha while they are 440 kg / ha and 2,000 kg / ha for the control respectively. This study clearly shows that the tufts of Hyphaene thebaica improve millet production.© 2015 International Formulae Group. All rights reserved.Keywords: Tufts, Hyphaene thebaica, millet, yields, El Guéza, Marad

Contamination modalities of the ryegrass by the platinum group elements and the polycyclic aromatic hydrocarbons near the road ways

Notre travail de thèse a porté sur les modalités de dépôts de PGE et HAP sur le fourrage à partir d’un bio-accumulateur (ray-grass). Les cinétiques du dépôt de PGE et HAP sur les plants de ray-grass exposé en bordure d’autoroute ont montré que l’essentiel de la contamination s’effectue durant les premières semaines d’exposition, et aussi que ces contaminants restent fixés au ray-grass au moins cinq semaines après son retrait de l’autoroute. L’étude de l’influence des conditions du trafic a montré un faible impact de l’autoroute sur la contamination du ray-grass en PGE et HAP par rapport à une route nationale, suggérant que le dépôt de PGE et HAP sur le ray-grass est beaucoup plus lié aux propriétés de leurs émissions par les véhicules que par le nombre de véhicules. La spatialisation de l’exposition du fourrage en PGE et HAP à l’échelle parcellaire a révélé une diminution significative des concentrations de Pd, Rh et HAP du ray-grass avec l’éloignement de la source d’émission.Our thesis work concerned the methods of PGE and PAH deposits on fodder using a bio-accumulator (ryegrass). The deposit kinetics of PGE and PAH on ryegrass exposed in the vicinity of a highway showed that the main part of the contamination is carried out during the first weeks of exposure, and also that these contaminants remain fixed on the ryegrass at least five weeks after its removal from the highway. The study of the traffic conditions influence showed a weak impact of the highway on the ryegrass contamination by PGE and PAH compared to a rural road, suggesting that the PGE and PAH deposits on the ryegrass are much more related to the emission properties from the vehicles than to the number of vehicles. The spatialization of the fodder exposure in PGE and PAH on a fodder plot scale revealed a significant reduction of the Pd, Rh and PAH concentrations of the ryegrass with the distance of the emission source

Modalités de contamination du ray-grass par les éléments du groupe platine et les hydrocarbures aromatiques polycycliques à proximité des voies routières

Our thesis work concerned the methods of PGE and PAH deposits on fodder using a bio-accumulator (ryegrass). The deposit kinetics of PGE and PAH on ryegrass exposed in the vicinity of a highway showed that the main part of the contamination is carried out during the first weeks of exposure, and also that these contaminants remain fixed on the ryegrass at least five weeks after its removal from the highway. The study of the traffic conditions influence showed a weak impact of the highway on the ryegrass contamination by PGE and PAH compared to a rural road, suggesting that the PGE and PAH deposits on the ryegrass are much more related to the emission properties from the vehicles than to the number of vehicles. The spatialization of the fodder exposure in PGE and PAH on a fodder plot scale revealed a significant reduction of the Pd, Rh and PAH concentrations of the ryegrass with the distance of the emission source.Notre travail de thèse a porté sur les modalités de dépôts de PGE et HAP sur le fourrage à partir d'un bio-accumulateur (ray-grass). Les cinétiques du dépôt de PGE et HAP sur les plants de ray-grass exposé en bordure d'autoroute ont montré que l'essentiel de la contamination s'effectue durant les premières semaines d'exposition, et aussi que ces contaminants restent fixés au ray-grass au moins cinq semaines après son retrait de l'autoroute. L'étude de l'influence des conditions du trafic a montré un faible impact de l'autoroute sur la contamination du ray-grass en PGE et HAP par rapport à une route nationale, suggérant que le dépôt de PGE et HAP sur le ray-grass est beaucoup plus lié aux propriétés de leurs émissions par les véhicules que par le nombre de véhicules. La spatialisation de l'exposition du fourrage en PGE et HAP à l'échelle parcellaire a révélé une diminution significative des concentrations de Pd, Rh et HAP du ray-grass avec l'éloignement de la source d'émissio

A global perspective on soil science education at third educational level; knowledge, practice, skills and challenges

The pivotal role of soil as a resource is not fully appreciated by the general public. Improving education in soil science represents a challenge in a world where soil resources are under serious threat. Today’s high school students, the world’s future landowners, agriculturalists, and decision makers, have the potential to change society’s apathy towards soils issues. This research aimed to compare the level of soil education in high and/or secondary schools in forty-three countries worldwide, together comprising 62% of the world's population. Comparisons were made between soil science content discussed in educationally appropriate textbooks via a newly proposed soil information coefficient (SIC). Interviews with teachers were undertaken to better understand how soil science education is implemented in the classroom. Statistical analyses were investigated using clustering. Results showed that gaps in soil science education were most commonly observed in countries where soil science is a non-compulsory or optional subject. Soil science concepts are predominantly a part of geography or environmental science curricula. Consequently, considerable variability in soil science education systems among investigated countries exists. Soil information coefficient‘s outcomes demonstrated that a methodological approach combining textbooks and the use of modern digitally based strategies in the educational process significantly improved soil education performances. Overall, soil science education is under-represented in schools worldwide. Dynamic new approaches are needed to improve pivotal issues such as: i) promoting collaborations and agreements between high school and universities; ii) encouraging workshops and practical exercises such as field activities; and, iii) implementing technology tools. This, in turn, will prepare the next generation to contribute meaningfully towards solving present and future soil problems

Pollution maps of grass contamination by platinum group elements and polycyclic aromatic hydrocarbons from road traffic

The increase in deposition of air pollutants such as the platinum group elements (PGEs) Pt, Pd and Rh, and polycyclic aromatic hydrocarbons (PAHs) from vehicles on plants has raised concerns about the risk for the quality of food and, in turn, for human health. Here, we report the first pollution maps of PGEs and PAHs at the agricultural scale. PGEs have recently emerged in ecosystems due to their massive use as catalysts in the automobile industry. PAHs are combustion by-products known for their carcinogenic properties. PAHs and PGEs emitted by vehicles can enter the food chain through deposition on plants growing near roads. Despite many investigations of PAHs and PGEs, knowledge on their spatial distribution near roads is very scarce. Here, we assessed their localization on the scale of an agricultural field close to a road with 7200 vehicles per day. While classical studies usually involve direct measurements of plants growing in the field, we used an alternative experimental approach to allow an unambiguous assessment of the pollution impact. Ryegrass (Lolium perenne) was first cultivated in pots in a closed greenhouse to isolate the plants from the outdoor atmosphere. Then, ryegrass pots were transferred to the agricultural field. The spatial distribution of PGEs and PAHs was assessed by placing ryegrass

Pollution maps of grass contamination by platinum group elements and polycyclic aromatic hydrocarbons from road traffic

The increase in deposition of air pollutants such as the platinum group elements (PGEs) Pt, Pd and Rh, and polycyclic aromatic hydrocarbons (PAHs) from vehicles on plants has raised concerns about the risk for the quality of food and, in turn, for human health. Here, we report the first pollution maps of PGEs and PAHs at the agricultural scale. PGEs have recently emerged in ecosystems due to their massive use as catalysts in the automobile industry. PAHs are combustion by-products known for their carcinogenic properties. PAHs and PGEs emitted by vehicles can enter the food chain through deposition on plants growing near roads. Despite many investigations of PAHs and PGEs, knowledge on their spatial distribution near roads is very scarce. Here, we assessed their localization on the scale of an agricultural field close to a road with 7200 vehicles per day. While classical studies usually involve direct measurements of plants growing in the field, we used an alternative experimental approach to allow an unambiguous assessment of the pollution impact. Ryegrass (Lolium perenne) was first cultivated in pots in a closed greenhouse to isolate the plants from the outdoor atmosphere. Then, ryegrass pots were transferred to the agricultural field. The spatial distribution of PGEs and PAHs was assessed by placing ryegrass

Modalités de contamination du ray-grass par les éléments du groupe platine et les hydrocarbures aromatiques polycycliques à proximité des voies routières

Notre travail de thèse a porté sur les modalités de dépôts de PGE et HAP sur le fourrage à partir d un bio-accumulateur (ray-grass). Les cinétiques du dépôt de PGE et HAP sur les plants de ray-grass exposé en bordure d autoroute ont montré que l essentiel de la contamination s effectue durant les premières semaines d exposition, et aussi que ces contaminants restent fixés au ray-grass au moins cinq semaines après son retrait de l autoroute. L étude de l influence des conditions du trafic a montré un faible impact de l autoroute sur la contamination du ray-grass en PGE et HAP par rapport à une route nationale, suggérant que le dépôt de PGE et HAP sur le ray-grass est beaucoup plus lié aux propriétés de leurs émissions par les véhicules que par le nombre de véhicules. La spatialisation de l exposition du fourrage en PGE et HAP à l échelle parcellaire a révélé une diminution significative des concentrations de Pd, Rh et HAP du ray-grass avec l éloignement de la source d émission.Our thesis work concerned the methods of PGE and PAH deposits on fodder using a bio-accumulator (ryegrass). The deposit kinetics of PGE and PAH on ryegrass exposed in the vicinity of a highway showed that the main part of the contamination is carried out during the first weeks of exposure, and also that these contaminants remain fixed on the ryegrass at least five weeks after its removal from the highway. The study of the traffic conditions influence showed a weak impact of the highway on the ryegrass contamination by PGE and PAH compared to a rural road, suggesting that the PGE and PAH deposits on the ryegrass are much more related to the emission properties from the vehicles than to the number of vehicles. The spatialization of the fodder exposure in PGE and PAH on a fodder plot scale revealed a significant reduction of the Pd, Rh and PAH concentrations of the ryegrass with the distance of the emission source.NANCY-INPL-Bib. électronique (545479901) / SudocSudocFranceF

Pollution maps of grass contamination by platinum group elements and polycyclic aromatic hydrocarbons from road traffic

The increase in deposition of air pollutants such as the platinum group elements (PGEs) Pt, Pd and Rh, and polycyclic aromatic hydrocarbons (PAHs) from vehicles on plants has raised concerns about the risk for the quality of food and, in turn, for human health. Here, we report the first pollution maps of PGEs and PAHs at the agricultural scale. PGEs have recently emerged in ecosystems due to their massive use as catalysts in the automobile industry. PAHs are combustion by-products known for their carcinogenic properties. PAHs and PGEs emitted by vehicles can enter the food chain through deposition on plants growing near roads. Despite many investigations of PAHs and PGEs, knowledge on their spatial distribution near roads is very scarce. Here, we assessed their localization on the scale of an agricultural field close to a road with 7200 vehicles per day. While classical studies usually involve direct measurements of plants growing in the field, we used an alternative experimental approach to allow an unambiguous assessment of the pollution impact. Ryegrass (Lolium perenne) was first cultivated in pots in a closed greenhouse to isolate the plants from the outdoor atmosphere. Then, ryegrass pots were transferred to the agricultural field. The spatial distribution of PGEs and PAHs was assessed by placing ryegrass pots 0 m, 10 m, 25 m and 50 m from the road. This method thus allowed the measurement of PGE and PAH deposit from vehicle emissions during a known timeframe. After a one-month exposure, the PGE and PAH concentrations in ryegrass samples were analyzed by inductively coupled plasma mass spectrometry (ICP-MS) and high-pressure liquid chromatography (HPLC), respectively. Our results demonstrate a significant effect of pollution by the outdoor atmosphere for Pd and PAHs. Indeed, the concentrations increased by a factor of 1.5 for Pd and by a factor of 7 for PAHs after one month's exposure in the isolated pasture. The results also demonstrate clearly the impact of road traffic. Indeed, the highest PGE and PAH concentrations were detected in ryegrass exposed at the road site. Pd and PAH concentrations decreased significantly up to 39% and 60%, respectively, from 0 to 50 m away from the road. The pollution maps show that the maximum depositions occur precisely along the road plan. The highest pollution levels of grasses of 23 ng Pd/g grass and 260 ng PAHs/g grass dry weight were recorded between 0 and 10 m on both sides of the road. Pollution maps should thus help to assess more precisely the impact of road traffic on food quality