Caractérisation des systèmes de production à base de riz pluvial strict dans les exploitations agricoles de la zone Sud-soudanienne du Burkina Faso

Au Burkina Faso, le riz occupe la 4ème place des céréales tant du point de vue des superficies, de la production que de la consommation annuelle par habitant.  Cependant, la production nationale est faible et ne couvre que 47% des besoins des populations. Au Burkina trois, types de rizicultures se côtoient ; la riziculture pluviale ; la riziculture de bas-fond et la riziculture irriguée. La riziculture pluviale  offre un fort potentiel mais est mal maîtrisée avec de faibles rendements. Cette étude a été conduite sous forme d’enquête auprès de 157 producteurs afin  d’identifier les potentiels et les contraintes de la riziculture pluviale dans la zone  Ouest du Burkina. Les résultats montrent une récente introduction de la riziculture pluviale dans la zone. La superficie individuelle moyenne est de 0,81 ha. Les  rendements moyens sont d’environ 1075 kg/ha. Les quantités d’engrais par hectare sont faibles et sont en moyenne de 44,5 kg pour l’azote, 25,5 kg pour le phosphore et 15,5 kg pour le potassium. Le riz pluvial est cultivé en pure sans rotation régulière. La faible maîtrise de l’itinéraire technique de production nécessite une formation des producteurs pour accroître les rendements et booster la production du riz pluvial.© 2015 International Formulae Group. All rights reserved.Mots clés : Riz pluvial, rendement, enquêtes, itinéraire technique

Effet des précédents culturaux et de différents niveaux d’azote sur la productivité du riz pluvial strict sur sols ferrugineux tropicaux de la zone sudsoudanienne du Burkina Faso

L’azote constitue un élément essentiel dans la nutrition minérale du riz. Au Burkina Faso, le riz pluvial entre de plus en plus dans les assolements. Cependant, le  rendement du riz pluvial reste largement en deçà du potentiel des variétés. Afin de contribuer à une meilleure connaissance de la nutrition minérale du riz pluvial, un dispositif expérimental en split plot a été mis en place en station de recherche de Farako-Bâ en 2013 et 2014 pour évaluer l’effet des rotations et de la fertilisation azotée sur le rendement. Les résultats montrent que les meilleurs précédents du riz pluvial sont les légumineuses niébé et arachide. Ces deux précédents permettent un gain de rendements respectivement de 104% et 92% par rapport à la  monoculture du riz. La dose de 90 kg N/ha a permis d’obtenir le rendement paddy le plus élevé soit une augmentation de 395% par rapport à la dose sans apport d’azote 0 kg N/ha et le poids de 1000 grains le plus élevé. Cependant la dose agronomique la plus efficace quel que soit le précédent cultural est de 60 kg N/ha. Les rotations et les doses d’azote ont un effet sur l’augmentation des rendements du riz paddy en culture pluviale.© 2015 International Formulae Group. All rights reserved.Mots clés: Riz pluvial, rotations, azote, légumineuses, Burkina Faso. Effect of previous crops and different nitrogen levels on the productivity of upland  rice on ferruginous tropical soils of the South Sudan region of  Burkina FasoNitrogen is an essential element in the mineral nutrition of rice. In Burkina Faso, more and more, upland rice enters in the crop rotation. However, the yield of upland rice remains under the potential of varieties. To contribute to a better understanding of the mineral nutrition of upland rice, an experimental split plot was tested in Farako-Bâ research station in 2013 and 2014. This was to evaluate the effect of crop rotations and the effect of nitrogen fertilization on yield of upland rice. The results show that the best previous crops of upland rice are legumes, cowpea and peanut. Both previous crops allow a gain of respectively 104% and 92% of yields compared to rice monoculture. The dose of 90 kg N/ha permitted to have highest paddy yield and an increase of 395% compared to the dose without nitrogen 0 kg N/ha and the highest weight of 1000 grains. However, the most effective agronomic dose regardless of the previous crop is obtained with the dose of 60 kg N/ha. Crops rotation and nitrogen level have an effect on upland rice yield.© 2015 International Formulae Group. All rights reserved.Keywords: Upland rice, rotations, nitrogen, legumes, Burkina Faso

EVALUATION OF THE GROUNDWATER QUALITY IN A CLOSED INDUSTRIAL LANDFILL

The study parameters: pH, conductivity, salinity, Total Dissolved Solids (TDS), Turbidity, Total Suspended Solids (TSS) and Chemical Oxygen Demand (COD) of groundwater in a closed industrial landfill, subject to the waste discharges of city of Bacau (East Romania), shows that the water quality of the different sampling points is variable. This difference is noted at the level of conductivity, TDS, turbidity, TSS and COD. These differences, however parameters are substantially higher compared the value of the legislation in groundwater Romania. Salinity remains relatively high at the point of sample P1 (0.7). The pH values are comprising in the range of reference values (6.5 to 7.4). The results also showed very strong correlations (r> 0.8) between Conductivity-Salinity, Conductivity -TDS, Salinity, TDS, Turbidity.-TSS, COD and TSS-Turbidity-COD. The strong correlation (0.5 0.8) were noted between Turbidity- Conductivity, Turbidity-Salinity, Turbidity, TDS, TSS conductivity, TSS-Salinity, TSS, TDS, COD, conductivity, salinity, COD, COD-TDS. Principal Component Analysis (PCA) also highlighted groundwater mineralization events of this landfill and possible pollution by organic matter

EVALUATION OF THE GROUNDWATER QUALITY IN A CLOSED INDUSTRIAL LANDFILL

The study parameters: pH, conductivity, salinity, Total Dissolved Solids (TDS), Turbidity, Total Suspended Solids (TSS) and Chemical Oxygen Demand (COD) of groundwater in a closed industrial landfill, subject to the waste discharges of city of Bacau (East Romania), shows that the water quality of the different sampling points is variable. This difference is noted at the level of conductivity, TDS, turbidity, TSS and COD. These differences, however parameters are substantially higher compared the value of the legislation in groundwater Romania. Salinity remains relatively high at the point of sample P1 (0.7). The pH values are comprising in the range of reference values (6.5 to 7.4). The results also showed very strong correlations (r> 0.8) between Conductivity-Salinity, Conductivity -TDS, Salinity, TDS, Turbidity.-TSS, COD and TSS-Turbidity-COD. The strong correlation (0.5 0.8) were noted between Turbidity- Conductivity, Turbidity-Salinity, Turbidity, TDS, TSS conductivity, TSS-Salinity, TSS, TDS, COD, conductivity, salinity, COD, COD-TDS. Principal Component Analysis (PCA) also highlighted groundwater mineralization events of this landfill and possible pollution by organic matter

Influence des haies de Jatropha sur le rendement d’une culture de sorgho (Sorghum vulgare) dans la zone Ouest du Burkina Faso: cas du terroir de Torokoro

Dans un contexte de désertification et avec la crise énergétique, un bon nombre d’acteurs de développement au Burkina Faso s’est intéressé au Jatropha curcas L. comme source d’énergie et de durabilité des productions. Afin d’évaluer l’influence de Jatropha sur les propriétés chimiques du sol et la productivité du sorgho associée, des essais ont été suivis pendant trois ans dans le terroir de Torokoro en zone Sud soudanienne de pluviométrie d’environ 1200 mm. Les plants de Jatropha, âgés de 6 ans, sont plantés aux écartements de 5 m entre les lignes et 2 m entre les plants. Le dispositif expérimental comporte trois blocs composés chacun de deux parcelles de 400 m2 correspondants aux 2 traitements: une par celle avec l’association sorgho-Jatropha et une parcelle en culture pure de sorgho (témoin). Les prélèvements de sol ont été effectués sous houppier, à 1 m et2m de la haie. Les résultats indiquent que Jatropha améliore la teneur du sol en carbone de 10% et de 8% en matière organique par rapport au témoin. Jatropha est aussi source de phosphore et de potassium et influence positivement la productivité du sorgho. Jatropha améliore donc les propriétés chimiques du sol et la productivité du sorgho.© 2015 International Formulae Group. All rights reserved.Mots clés: Jatropha curcas L., sol, Sorgho, Rendements, propriétés chimiques, Burkina FasoEnglish Title: Influence of Jatropha hedges on the yield of a sorghum crop (Sorghum vulgare) in the western region of Burkina Faso: case of Torokoro localityEnglish AbstractIn a context of desertification and with the energy crisis, a number of development actors in Burkina Faso became interested in Jatropha curcas L. as a source of energy and sustainability of production. To assess the influence of Jatropha on soil chemical properties and on the productivity of associated sorghum, experiments were followed for three years in the village of Torokoro in south sudanian region, with a rainfall of about 1200 mm. Jatropha plants, aged 6, are planted at 5 m between rows and 2 m between plants. The experiment consisted of three blocks each consisting of two plots of 400 m2 corresponding to two treatments: a plot with sorghum and Jatropha in association and a plot with sorghum only (control). Soil samples were taken under crown, at 1m and 2 m from the hedge. The results indicate that Jatropha improves the carbon content in the soil of 10%, and the organic matter content of 8% compared to the control. Jatropha is also a source of phosphorus and potassium and positively influences the productivity of sorghum. Therefore, Jatropha improves the chemical properties of soil and productivity of sorghum.© 2015 International Formulae Group. All rights reserved.Keywords: Jatropha curcas L., soil, Sorghum, yields, chemical properties, Burkina Fas

Caractérisation des systèmes de production de Jatropha dans les exploitations agricoles de la zone Ouest du Burkina Faso

La production agricole est la principale source de développement socio-économique au Burkina Faso. Depuis les années 2000, la promotion du Biocarburant suscite un regain d’intérêt pour la plantation de Pourghère (Jatropha curcas L.). Dans 14 villages de la zone Ouest du Burkina Faso, une enquête semistructurée basée sur un questionnaire a été appliquée auprès de 210 producteurs de Jatropha. Les résultats des enquêtes indiquent que la production de Jatropha est récente. La superficie des plantations de Jatropha varie entre 7,5 et 30 ha par village. L’écartement le plus adopté pour la plantation de Jatropha est de 5 m entre les lignes et 2 m entre les plants (5 m × 2 m), soit une densité de 1071 plants/ha. Une proportion de 80,4% des producteurs enquêtés indique avoir 4 à 7 ans d’expérience dans la culture de Jatropha. Les rendements varient entre 300 et 700 kg/ha. Pour 78,5% des exploitants, leur engagement dans la culture de Jatropha a été motivé par les structures de promotion de Jatropha. Plus de 90% des producteurs pratiquent la technique de la pépinière-transplantation et 70% pratiquent la culture associée au Jatropha. Les enquêtes révèlent que 70% des producteurs associent les légumineuses au Jatropha et que 22% des producteurs pratiquent la fertilisation de Jatropha. L’application des traitements phytosanitaires au Jatropha peu pratiquée, ne concerne que 11% des producteurs.© 2015 International Formulae Group. All rights reserved.Mots clés: Biocarburant, pourghère (Jatropha curcas L.), enquêtes, exploitants, Burkina FasoEnglish Title:  Characterization of the systems of production of Jatropha in the agricultural exploitations of the West zone of Burkina FosoEnglish AbstractThe agricultural production is the main source of socioeconomic development of Burkina Faso. Since the years 2000, the promotion of biofuel causes a renewal of interest toward Jatropha curcas L. In 14 villages of the West zone of Burkina Faso, a semi-structured investigation based on a questionnaire has been applied on 210 farmers of Jatropha. The results of the investigations indicate that the production of Jatropha is recent. The surfaces of plantations of Jatropha vary between 7.5 and 30 ha per village. The more adopted spacing for the plantation of Jatropha is of 5 m between the lines and 2 m between the plantations (5 m × 2 m), thus a density of 1071 plants/ha. A proportion of 80.4% of producers investigated have 4 to 7 years of experience in the culture of Jatropha. The yields vary between 300 and 700 kg/ha. For 78.5% of farmers, their commitment in the production of Jatropha has been motivated by the structures of promotion of Jatropha. More than 90% of the producers practice the technique of the nursery-transplantation and 70% grow cereal associated with Jatropha. The investigations reveal that 70% of producers associate vegetables with Jatropha and that 22% of producers fertilize Jatropha fields. The rate of the application of pesticides in the field of Jatropha is little, it concerns only 11% of producers.© 2015 International Formulae Group. All rights reserved.Keywords: Biofuel, Jatropha curcas L., investigations, producers, Burkina Fas

Impact of Jatropha plantation on soil chemical and biological properties in the South Sudanian region in Burkina Faso

In Burkina Faso, about 100,000 ha of Jatropha were planted during the past 10 years. Despite this enthusiasm, few results exist on the impact of the plant on soil properties. This study contributes to better knowledge of Jatropha farming and was carried out in 2013 with Jatropha farmers in Torokoro and Tin villages in the south Sudanian zone of Burkina Faso (rainfall 900-1200 mm). Data collection plots of 400 m2 repeated 3 times were installed in 3 farmers’ fields in each village. Soil samples were collected at 3 distances (D0= under the crown, D1= 1m and D2= 2m) from the Jatropha trees lines and in a fallow as a control sample for each field. The results showed significant differences between distances for soil pH. Soil nutrients increase with distance from the crown (from 9.33% to 12.20%) for available phosphorus in Torokoro-6 years and decrease from 22.45% to 23.71% in Torokoro-2 years). Soil respiration and microbial biomass decreases also with distance. The density of spores of mycorrhizal fungi is higher for the control soils (14.64%) and it decreases from crown to 2m (from 2.22% to 9.53% in Tin-2 years). The study showed the contribution of Jatropha trees on soil fertility improvement.© 2015 International Formulae Group. All rights reserved.Keywords: Jatropha, soil biology, microbial biomass, carbon, nitrogen, Burkina Fas

Early stage litter decomposition across biomes

Through litter decomposition enormous amounts of carbon is emitted to the atmosphere. Numerous large-scale decomposition experiments have been conducted focusing on this fundamental soil process in order to understand the controls on the terrestrial carbon transfer to the atmosphere. However, previous studies were mostly based on site-specific litter and methodologies, adding major uncertainty to syntheses, comparisons and meta-analyses across different experiments and sites. In the TeaComposition initiative, the potential litter decomposition is investigated by using standardized substrates (Rooibos and Green tea) for comparison of litter mass loss at 336 sites (ranging from −9 to +26 °C MAT and from 60 to 3113 mm MAP) across different ecosystems. In this study we tested the effect of climate (temperature and moisture), litter type and land-use on early stage decomposition (3 months) across nine biomes. We show that litter quality was the predominant controlling factor in early stage litter decomposition, which explained about 65% of the variability in litter decomposition at a global scale. The effect of climate, on the other hand, was not litter specific and explained <0.5% of the variation for Green tea and 5% for Rooibos tea, and was of significance only under unfavorable decomposition conditions (i.e. xeric versus mesic environments). When the data were aggregated at the biome scale, climate played a significant role on decomposition of both litter types (explaining 64% of the variation for Green tea and 72% for Rooibos tea). No significant effect of land-use on early stage litter decomposition was noted within the temperate biome. Our results indicate that multiple drivers are affecting early stage litter mass loss with litter quality being dominant. In order to be able to quantify the relative importance of the different drivers over time, long-term studies combined with experimental trials are needed.This work was performed within the TeaComposition initiative, carried out by 190 institutions worldwide. We thank Gabrielle Drozdowski for her help with the packaging and shipping of tea, Zora Wessely and Johannes Spiegel for the creative implementation of the acknowledgement card, Josip Dusper for creative implementation of the graphical abstract, Christine Brendle for the GIS editing, and Marianne Debue for her help with the data cleaning. Further acknowledgements go to Adriana Principe, Melanie Köbel, Pedro Pinho, Thomas Parker, Steve Unger, Jon Gewirtzman and Margot McKleeven for the implementation of the study at their respective sites. We are very grateful to UNILEVER for sponsoring the Lipton tea bags and to the COST action ClimMani for scientific discussions, adoption and support to the idea of TeaComposition as a common metric. The initiative was supported by the following grants: ILTER Initiative Grant, ClimMani Short-Term Scientific Missions Grant (COST action ES1308; COST-STSM-ES1308-36004; COST-STM-ES1308-39006; ES1308-231015-068365), INTERACT (EU H2020 Grant No. 730938), and Austrian Environment Agency (UBA). Franz Zehetner acknowledges the support granted by the Prometeo Project of Ecuador's Secretariat of Higher Education, Science, Technology and Innovation (SENESCYT) as well as Charles Darwin Foundation for the Galapagos Islands (2190). Ana I. Sousa, Ana I. Lillebø and Marta Lopes thanks for the financial support to CESAM (UID/AMB/50017), to FCT/MEC through national funds (PIDDAC), and the co-funding by the FEDER, within the PT2020 Partnership Agreement and Compete 2020. The research was also funded by the Portuguese Foundation for Science and Technology, FCT, through SFRH/BPD/107823/2015 (A.I. Sousa), co-funded by POPH/FSE. Thomas Mozdzer thanks US National Science Foundation NSF DEB-1557009. Helena C. Serrano thanks Fundação para a Ciência e Tecnologia (UID/BIA/00329/2013). Milan Barna acknowledges Scientific Grant Agency VEGA (2/0101/18). Anzar A Khuroo acknowledges financial support under HIMADRI project from SAC-ISRO, India

Early stage litter decomposition across biomes

[Departement_IRSTEA]Territoires [TR1_IRSTEA]SEDYVINInternational audienceThrough litter decomposition enormous amounts of carbon is emitted to the atmosphere. Numerous large-scale decomposition experiments have been conducted focusing on this fundamental soil process in order to understand the controls on the terrestrial carbon transfer to the atmosphere. However, previous studies were mostly based on site-specific litter and methodologies, adding major uncertainty to syntheses, comparisons and meta-analyses across different experiments and sites. In the TeaComposition initiative, the potential litter decomposition is investigated by using standardized substrates (Rooibos and Green tea) for comparison of litter mass loss at 336 sites (ranging fro