Digital assessment of soil-salinity dynamics after a major flood in the Niger River valley

Geoderma ◽  
2013 ◽  
Vol 207-208 ◽  
pp. 193-204 ◽  
Author(s):  
Didier Michot ◽  
Christian Walter ◽  
Issifou Adam ◽  
Yadji Guéro
Keyword(s):  
Soil Salinity ◽  
River Valley ◽  
Digital Assessment ◽  
Niger River

Soil salinity assessment using temporal series of Sentinel2 satellite images in irrigated paddy fields of Western Africa

2020 ◽  
Author(s):  
Moussa Issaka ◽  
Walter Christian ◽  
Michot Didier ◽  
Pichelin Pascal ◽  
Nicolas Hervé ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Soil Salinity ◽  
Ground Truth ◽  
Growing Season ◽  
Bare Soil ◽  
Atmospheric Effects ◽  
Ground Truth Data ◽  
Multi Temporal ◽  
Salinity Index ◽  
Niger River

<p>Salinization and alkalinization are worldwide among the soil degradation threats in irrigated schemes affecting soil productivity. Niger River basin irrigated schemes in the Sahel arid zone are no exception (ONAHA, 2011). The use of remote sensing for identifying and evaluating the level of these phenomena is an interesting tool. The launching of the Sentinel2 satellite constellation (2015) brings new perspectives with high spectral and temporal resolutions images. The aim of this study was to develop a methodology for detection of salt-affected soils in this climatic condition.</p><p>To achieve our goal, we used two types of data: remote sensing and ground truth data.</p><p>Two complementary approaches were used: one by observing salinity on bare soil by the use of salinity index (SI) and the other by observing the indirect effects of salinity on the vegetation during eight (8) rice growth phases  using vegetation index NDVI.</p><p>Remote sensing data were acquired from multi temporal sentinel2 images over 4 years (from 11/12/2015 to 30/11/2019). One hundred and fifty seven (157) images were downloaded (one image each 5 days) and corrected from atmospheric effects and some bands resampled to 5 m using python software. The salinity and vegetation indices were calculated. NDVI index was calculated and NDVI integral between NDVI curve and the threshold of 0.21 NDVI calculated for the eight growing cycles.</p><p>Ground truth data were collected in 2019 during the dry growing season (January – may 2019) from 24 calibration plots and 40 validation plots. One hundred and twenty (120) soil samples collected and analyzed for pH and electrical conductivity and finally forty six (46) biomass samples were collected, air dried and weighed for biomass yield and 46 grains samples collected for grain yield.</p><p>NDVI integral proved to be good indicator for yield variations and could distinguish crops behavior according to the growing period. It also makes it possible to distinguish plots which were not cultivated or with weak growth due to strong constraints of which the main one is salinity. It showed also that the effect of salinity on growth differs according to the growing season and the possibility of managing irrigation. Bare soil analysis distinguishes fields with different salinity indexes despite the low number of dates for which bare soil can be observed.</p><p>Ascending Hierarchical Classification (AHC) enabled to identify four classes of NDVI dynamics over time and bare soil salinity index. High saline soils according to direct soil measurements were related to the class characterized by high frequency of no-cultivation during the dry season and low NDVI integral during the wet season. Multi-temporal Sentinel2 images analysis enabled therefore to detect rice crop fields affected by salinity through its influence on crop behavior. This approach will be tested over the whole paddy schemes of the Niger River valley.</p>

The spread ofBiomphalaria pfeifferiin the Niger River valley, Niger

2003 ◽  
Vol 97 (2) ◽  
pp. 209-212 ◽  
Author(s):  
R. Labbo ◽  
A. Garba ◽  
J. P. Louboutin-Croc ◽  
J. C. Ernould ◽  
B. Sellin ◽  
...  
Keyword(s):  
River Valley ◽  
Niger River

Regional-scale Assessment of Soil Salinity in the Red River Valley Using Multi-year MODIS EVI and NDVI

2010 ◽  
Vol 39 (1) ◽  
pp. 35-41 ◽  
Author(s):  
D. B Lobell ◽  
S. M. Lesch ◽  
D. L. Corwin ◽  
M. G. Ulmer ◽  
K. A. Anderson ◽  
...  
Keyword(s):  
Soil Salinity ◽  
Regional Scale ◽  
River Valley ◽  
Red River ◽  
Red River Valley ◽  
Scale Assessment ◽  
Modis Evi

scholarly journals Interactions between Schistosoma haematobium group species and their Bulinus spp. intermediate hosts along the Niger River Valley

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Tom Pennance ◽  
Fiona Allan ◽  
Aidan Emery ◽  
Muriel Rabone ◽  
Jo Cable ◽  
...  
Keyword(s):  
Schistosoma Haematobium ◽  
River Valley ◽  
Intermediate Hosts ◽  
Niger River ◽  
Group Species

scholarly journals Freshwater snails of biomedical importance in the Niger River Valley: evidence of temporal and spatial patterns in abundance, distribution and infection with Schistosoma spp.

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Muriel Rabone ◽  
Joris Hendrik Wiethase ◽  
Fiona Allan ◽  
Anouk Nathalie Gouvras ◽  
Tom Pennance ◽  
...  
Keyword(s):  
Intermediate Host ◽  
Dry Season ◽  
River Valley ◽  
Freshwater Snails ◽  
Sampling Effort ◽  
Irrigation Canals ◽  
Entire Study ◽  
Bulinus Truncatus ◽  
Temporal And Spatial ◽  
Niger River

Abstract Background Sound knowledge of the abundance and distribution of intermediate host snails is key to understanding schistosomiasis transmission and to inform effective interventions in endemic areas. Methods A longitudinal field survey of freshwater snails of biomedical importance was undertaken in the Niger River Valley (NRV) between July 2011 and January 2016, targeting Bulinus spp. and Biomphalaria pfeifferi (intermediate hosts of Schistosoma spp.), and Radix natalensis (intermediate host of Fasciola spp.). Monthly snail collections were carried out in 92 sites, near 20 localities endemic for S. haematobium. All bulinids and Bi. pfeifferi were inspected for infection with Schistosoma spp., and R. natalensis for infection with Fasciola spp. Results Bulinus truncatus was the most abundant species found, followed by Bulinus forskalii, R. natalensis and Bi. pfeifferi. High abundance was associated with irrigation canals for all species with highest numbers of Bulinus spp. and R. natalensis. Seasonality in abundance was statistically significant in all species, with greater numbers associated with dry season months in the first half of the year. Both B. truncatus and R. natalensis showed a negative association with some wet season months, particularly August. Prevalences of Schistosoma spp. within snails across the entire study were as follows: Bi. pfeifferi: 3.45% (79/2290); B. truncatus: 0.8% (342/42,500); and B. forskalii: 0.2% (24/11,989). No R. natalensis (n = 2530) were infected. Seasonality of infection was evident for B. truncatus, with highest proportions shedding in the middle of the dry season and lowest in the rainy season, and month being a significant predictor of infection. Bulinus spp. and Bi. pfeifferi showed a significant correlation of snail abundance with the number of snails shedding. In B. truncatus, both prevalence of Schistosoma spp. infection, and abundance of shedding snails were significantly higher in pond habitats than in irrigation canals. Conclusions Evidence of seasonality in both overall snail abundance and infection with Schistosoma spp. in B. truncatus, the main intermediate host in the region, has significant implications for monitoring and interrupting transmission of Schistosoma spp. in the NRV. Monthly longitudinal surveys, representing intensive sampling effort have provided the resolution needed to ascertain both temporal and spatial trends in this study. These data can inform planning of interventions and treatment within the region.

scholarly journals Exploitations Familiales de Production Agricole des Cercles de Niono et de Banamba (Mali): Caractérisation et Stratégies de Prise en Charge des Besoins en Rapport Avec L’intervention Pour le Développement Agricole et Rural

2017 ◽  
Vol 13 (13) ◽  
pp. 193
Author(s):  
Amadou Ndiaye ◽  
Yacouba Sangaré
Keyword(s):  
Rural Development ◽  
Agricultural Education ◽  
River Valley ◽  
Prise En Charge ◽  
Family Farm ◽  
Family Farms ◽  
Rural And Urban ◽  
The Family ◽  
Niger River ◽  
Peasant Family

The development of family farming is an important strategic option to support the food needs of the rural and urban populations. This is the reason it has been the subject of several studies which is based on characterization and typology to better orientate agricultural and rural development interventions. This study was conducted to characterize family farm in Mali and to determine the strategies to satisfy the country’s needs in rapport with the implementation of rural development. In doing this, field data were first collected in the family farms at Niono County (Niger River valley) and the Banamba County. After data collection, it was then analyzed in a systemic way. This analysis helps to characterize the family farm of Mali as a “Traditional peasant farm”. In Niono County, ‘peasant family farm’ which ensures its food self-sufficiency is centered on the production unit with an option of diversification. In Banamba County, “peasant family farm’ centered on unity of consumption develops food security strategy through pluri-activity. Thus, despite the intensity of government intervention, particularly in the area of Niger River Valley, malian “peasant family farmg” did not turn into “Modern family farm business”. In doing this, intervention for agricultural and rural development should move based on its strategies and practices from a sectorial approach to a systemic approach. This passage from the deterministic and holistic paradigm to the systemic and interactionist paradigm, should better redefine agricultural education and agricultural subsidy in relation with the structure of production.

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