La dynamique spatio-temporelle de l'occupation du sol et les facteurs de dégradation ont été analysés à partir des images Landsat de 1972, de 1990 et de 2008, de la télédétection et d'un système d'information géographique (SIG), dans le Parc National du W et sa périphérie dans le Nord-Ouest du Bénin. L'objectif de la présente étude est d'une part d'analyser la dynamique de l'occupation du sol entre 1972 et 2008, et d'autre part, de déterminer les facteurs de dégradation du couvert végétal. Des enquêtes socioéconomiques ont été réalisées dans les villages riverains du Parc National du W. La classification supervisée par maximum de vraisemblance a été appliquée. Deux matrices de transition ont permis de mettre en évidence les conversions subies par les différentes unités d'occupation du sol. Les formations forestières ont régressé de 22,70% à 17,00% entre 1972 et 2008. Les forêts galeries dégradées quasi inexistantes en 1972 se sont reconstituées à partir de 1990 et sont passées de 0,60% à 2,85% en 2008. Quant aux forêts denses ainsi que les forêts claires et savanes boisées, elles ont subi une régression en terme de superficie (0,23% en 1972 à 0,09% en 2008 et de 17,90% à 12,91% respectivement). Par contre, les savanes arborées et arbustives ont connu une légère diminution (73% en 1972 à 66,65% en 2008) tandis que les mosaïques de champs et jachères ont connu une augmentation de leur superficie (1,38% en 1972 à 13,97% en 2008), soit plus de 10 fois leur superficie initiale de 1972. La démographie, l'agriculture et le surpâturage sont les trois principaux facteurs de dégradation du Parc National du W et de sa périphérie.

Purpose: To study the epidemiology and treatment modalities of urolithiasis at Urology Department of University Hospital of Cotonou. Materials and Methods: It was a retrospective and descriptive study over a 10 years period ranging from January 1st, 2004 to December 31st, 2013. One hundred and two patients who were hospitalized for symptomatic urolithiasis at the Urology Department of University Hospital of Cotonou were enrolled. Results: Hospital incidence of urolithiasis was 3.7%. Patients mean age was 39.6 years (extremes: 10 years to 73 years). Male to female ratio was 2.2. The main reason for consultation was renal colic for 81 patients (79.4%). Average duration of symptoms at presentation was 5 months (range: 1 day to 10 years). A total of 173 stones were identified with an average size of 12 mm (range: 1 mm to 95 mm). Calyceal stones were seen in 32.9% of cases, renal pelvis stones in 21.4% of cases, ureteral stones in 34.1% and bladder stones in 11.5% of cases. Open surgery was the main treatment for stones that could not be managed medically. 50.8% of patients underwent surgery with extraction of 116 stones. This represented 67.1% of all stones. 9 patients (8.8%) had expelled their stone during urination. The postoperative course was uneventful in 77.5% of cases. Conclusion: Modern treatment options for urolithiasis remain rudimentary in our health facilities. Open surgery is still the main stay of treatment in our countries with limited resources.

The present study is aimed at assessing the impact of different tillage practices and mulch input rates on soil erosion and soil properties in Central Benin. The experiment was carried out at two sites (Dan and Za-zounmè) using a randomized complete block design. The effect of three tillage practices: contour ridging (CR); slope ridging (SR) and no-tillage (NT) and four mulch input rates (0 t.ha-1; 3 t.ha-1; 5 t.ha-1, 7 t.ha-1) were investigated. The runoff, the soil and nutrients losses were measured during the major rainy seasons of 2018 and 2019. Bulk density, gravimetric moisture and water infiltration were collected in 2019. The effect of the interaction between tillage practices and mulch input rates were significant on runoff amount, runoff coefficient, soil loss, N, P, K losses and soil moisture. Over the investigated seasons, CR+7M decreased runoff amount, runoff coefficient, soil loss, N, P and K losses by 100% compared to the treatments. NT was found to be effective in runoff and soil erosion controlling when combined with a mulch quantity greater than 3 t.ha-1, NT+5M and NT+7M reduced the soil loss respectively by more than 30% compared to the farmer’s practice (SR+0M) at both sites. Contour ridge treatments yielded more soil moisture than no-tillage and slope ridge treatments. Whatever the tillage practice, the greatest gravimetric moisture were recorded on 5 t.ha-1 and 7 t.ha-1 plots (i.e. CR+7M, NT+7M and SR+7M). This study provides decision-makers with requisite information for effective soil erosion management in Benin where mechanization aids are limited.

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