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The increase in agricultural production as well as its nutritional quality at a cost bearable by producers is today a challenge in rural areas. Vermicompost is a low-cost organic amendment known for its effectiveness on agricultural productivity increase but little is diffused about its efficacy on nutritional quality. This study aimed to evaluate the benefits of vermicompost from cattle dung on Lagenaria siceraria yield and its edible parts content in mineral and in heavy metal compared to raw dung. The study was carried out in the region of Mankono the biggest area for L. siceraria production in Côte d’Ivoire during three cycle seasons. The experiment consisted of three treatments arranged in a complete randomized block design with four replicates. The agronomic parameters as yield, number of leaves and flowers per plant were evaluated. Also, mineral nutrients and heavy metal concentrations in roots, leaves and seeds were measured. Results showed that yield, number of leaves and flowers per plant were higher with the vermicompost than with the cattle manure and the control. The yield obtained with the vermicompost was 2.5 times and 20 times higher respectively than that with the cattle manure and the control. Mineral concentrations in roots, leaves and seeds were the highest with the vermicompost when heavy metal contents were the lowest. The present study indicates that vermicompost utilization improves the yield and the nutritional quality of the edible parts of L. siceraria and hence could be recommended to producers for increasing productivity with keeping the health and safety of human.

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This report presents a new large-scale test apparatus (LSTA) developed to assess the efficiency of a geosynthetic reinforcement for the limitation of deformations of a geosynthetic lining system (GLS) over a 0.5 m wide cavity. Two experiments were conducted. The first one involved a geosynthetic clay liner, a nonwoven needle-punched geotextile and a high-density polyethylene geomembrane. For the second experiment, a 50 kN/m polyvinyl alcohol geogrid was imbedded within the sand layer below the geosynthetic clay liner to provide reinforcement above the cavity. An overburden pressure varying from 10 to 100 kPa was applied to the top of the GLS. Strain gauges were used to measure the strain within the geogrid and the geomembrane. The results proved that the 50 kN/m geogrid reinforcement beneath the geomembrane reduced the maximum strain within the geomembrane, compared to the case where the geomembrane was unreinforced, by 25% on average. The results showed that the overall strain within the geomembrane was 31% to 42% less than that of the geogrid above the cavity. Finally, the results showed that the spatial distribution of the strain within the geomembrane and that of the geogrid differed because of a conical shape of the collapsed zone.