scholarly journals Influence of Anthropic and Topographic Factors on the Physicochemical Properties of the Soil around Temporary Pools in Ferlo, North Senegal

Author(s):  
Ndiabou Faye ◽  
Mariama Dalanda Diallo ◽  
Jean Luc Peiry ◽  
Aly Diallo ◽  
Aliou Guisse

The temporary ponds at Ferlo constitute wetlands whose pastoral activity is of paramount importance in the economy of Senegal. These zones are characterized by a fairly specific microclimate (soft and humid), a shallow depth of the water table, alternating phases of submersion and exudation whose functioning is linked to the soil. Thus the restoration and conservation of these wetlands requires a good knowledge of the soil factors. The objective of this study is to compare the physico-chemical parameters of the soil around temporary pools in grazed and ungrazed areas and different topographical units in order to determine their relative similarities. The samples taken at different horizons from seven soil pits (P1, P2, P3, P4, P5, P6 and P7) opened in the different morpho-pedological facies of two grazed ponds and one ungrazed pond were analyzed in the laboratory. The results obtained show that the soils of Ferlo have a sandy texture and low fertility in the slopes and plateaus. However, they have a balanced texture and average fertility in ponds and ungrazed areas. The factorial analysis made it possible to highlight three distinct soil classes. A class of sandy texture soil with very low chemical fertility comes from the plateau. A class of soil with a balanced texture which is rich in cation and calcium exchange capacity found in the low zones of strong mineralization. A last class rich in chemical element with a silty texture which is found in wooded areas. These results thus reveal the predominant influence of anthropic and topographic factors on the evolution and physico-chemical composition of the soil.

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Hudson Onen ◽  
Robinson Odong ◽  
Moses Chemurot ◽  
Frédéric Tripet ◽  
Jonathan K. Kayondo

Abstract Background Malaria is often persistent in communities surrounded by mosquito breeding habitats. Anopheles gambiae sensu lato exploit a variety of aquatic habitats, but the biotic determinants of its preferences are poorly understood. This study aimed to identify and quantify macroinvertebrates in different habitat types with determined water physico-chemical parameters to establish those preferred by An. gambiae s.l. larvae as well as their predators and competitors. Methods A field survey was conducted in Kibuye and Kayonjo villages located in the vicinity of the River Sezibwa, north-eastern Uganda to identify Anopheline larval habitats shared by aquatic insects. Habitats were geo-recorded and as streams, ponds, temporary pools and roadside ditches. From October to December 2017, random microhabitats/quadrats were selected from each habitat type, their water physico-chemical parameters (electrical conductivity, total dissolved solids, temperature and pH) were measured, and they were sampled for macroinvertebrates using standard dippers. All collected arthropod macroinvertebrates were then morphologically identified to family level and enumerated. Results Principal component analysis showed that the four larval habitat types were characterized by distinct physico-chemical parameter profiles. Ponds and streams had the highest number and diversity of macroinvertebrate insect taxa and sustained few An. gambiae s.l. larvae. Anopheles gambiae s.l. were more common in roadside ditches and particularly abundant in temporary pools which it commonly shared with Dytiscidae (predaceous diving beetles) and Culex spp. Cluster correlation analysis conducted on the abundance of these taxa within quadrats suggested that An. gambiae s.l. and Dytiscidae have the most similar patterns of microhabitat use, followed by Cybaeidae (water spiders). Whilst Culex spp. co-occurred with An. gambiae s.l. in some habitats, there was only partial niche overlap and no clear evidence of competition between the two mosquito taxa. Conclusions Ponds and streams are habitats that host the largest diversity and abundance of aquatic insect taxa. Anopheles gambiae s.l. larvae distinctively preferred temporary pools and roadside ditches, where they were exposed to few predators and no apparent competition by Culex spp. Further studies should aim to test the impact of Dytiscidae and Cybaeidae on An. gambiae s.l. dynamics experimentally. Graphical Abstract


2021 ◽  
Vol 50 (2) ◽  
pp. 351-360
Author(s):  
Akomolafe Gbenga Festus ◽  
Rahmad Zakaria

The relationships between soil factors and plant community characteristics of some wetlands invaded by Pneumatopteris afra and non-invaded ones were investigated. Sixty soil samples were obtained from six wetlands comprising three invaded and three non-invaded in Lafia, Nigeria using sixty quadrants arranged on six 200 m transects. The samples, after air-dried and sieved using 2 mm mesh were analysed for the physico-chemical properties which include pH, organic matter (OM), percentage nitrogen (% N), phosphorus (P), calcium (Ca), sodium (Na), potassium (K), magnesium (Mg), exchangeable acidity (EA), percentage base saturation (% BS), particle size, porosity, bulk density (BD), hydraulic conductivity (HC), and moisture content (MC) using standard methods. Direct ordination in canonical correspondence analysis was used to determine the influence of these soil factors on P. afra abundance, Shannon diversity, and species richness of both invaded and non-invaded sites. All sites differ from each other in terms of their physico-chemical parameters. The invaded sites appeared to be more acidic (pH = 3.22), less sandy, more porous (38.11%), low HC (1.23) as compared with non-invaded ones. Soil factors that favoured abundance of P. afra(% OM and EA) correlated negatively with Shannon diversity index of invaded sites which was positively influenced by % N, pH, and cation exchange capacity (CEC). At the non-invaded sites, Shannon index and density were influenced positively by % BS, pH, AP, and % N. All these observations showed that the soil factors played significant roles in the establishment of P. afra at the invaded sites, and also on the plant diversity at non-invaded sites.


2012 ◽  
Vol 2 (10) ◽  
pp. 1-3
Author(s):  
Gyaneswar Bhuyan ◽  
◽  
Dr. R. Anandhan Dr. R. Anandhan ◽  
V. kavitha V. kavitha

2007 ◽  
Vol 9 (3) ◽  
pp. 236-246
Author(s):  
P. D. Magesh ◽  
J. Santanakumar ◽  
P. Venkateshwaran ◽  
A. K. Abdul Nazar ◽  
R. Venkatesan ◽  
...  

2018 ◽  
Vol 8 (5) ◽  
pp. 48-50
Author(s):  
N.V. Lakina ◽  
◽  
A.I. Golovko ◽  
V.Yu. Doluda ◽  
V.G. Matveeva ◽  
...  

2020 ◽  
pp. 6-11
Author(s):  
Anton Kasatkin ◽  
Anna Nigmatullina ◽  
Mikhail Kopytov

The article presents the results of studies of osmolality and pH of 0,9 % sodium chloride of various manufacturers. To obtain data on the pH value, the data used in the passports are used, and the indicators of its osmolality are de- termined using laboratory tests. 0,9 % sodium chloride from different manufacturers has different pH and osmolality. Knowing the actual values of physico-chemical parameters can increase the accuracy of the results of future clinical studies, which compare the pharmacokinetics and pharmacodynamics of modern plasma-substituting solutions and a solution of 0,9 % sodium chloride.


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