To assess the influence of Jatropha curcas cultivation on maize yield in a cropping association, a study was conducted on the application farm of the Ecole Régionale d'Agriculture du Sud in Bingerville from 2015 to 2016. The study aimed to determine the appropriate Jatropha planting density to improve maize yield in a cropping association. The experiment consisted in setting up a randomized complete block design with three replications, including three treatments T1 (2*2m); T2 (3*2m) and T3 (4*2m) based on the spacing of Jatropha curcas plants compared to a control T0 (control without jatropha). Morphological and yield parameters of Jatropha curcas and maize were assessed respectively. The results obtained show that the Jatropha-maize association had no significant effect (P > 0.05) on the agro-morphological parameters (growth, development and yield) of Jatropha curcas regardless of the treatment. On the other hand, a significant effect (P < 0.05) of the Jatropha-maize association was observed on plant biomass and maize yield, particularly with treatment T2. In conclusion, this experiment demonstrates that it is possible to harmoniously integrate regular row spacing (intercropping) in Jatropha curcas plantations during the juvenile period of the trees provided that the main crop (Jatropha curcas) is at a spacing of 3*2 m.

The high price of chemical inputs has led producers to use other sources of fertilizer such as chicken manure. However, the direct and compost-free application of these wastes as practiced by producers is a potential source of soil acidification and environmental contamination that cannot adequately restore soil fertility. The objective of the study was to evaluate the effects of composting times on the chemical fertility of the composts produced. The study was carried out at the Jean Lorougnon Guédé University in the Tazibouo district of Daloa, in the centre-west of Côte d'Ivoire. Twelve (12) piles of chicken manure were made up of 3 piles per treatment corresponding to the different composting times (T14, T21, T28, T35 days). Four treatments rated T14, T21, T28 and T35 corresponding to 14, 21, 28 and 35 days of composting of the feces were compared to a control treatment T0 (composted chicken feces). The study found that composting chicken manure has positive effects on its chemical fertility by improving the levels of most of the physical and chemical parameters of the composts produced. As a result, composting has reduced concentrations of trace metal elements, such as iron and zinc, in composted chicken droppings, which at high soil levels become toxic to plants. Composting the manure for 14 days by improving the fertility of the composts produced can therefore be recommended to growers for a better chemical quality of the compost produced.

This study is focused on the soil morphological and physico-chemical characteristics of soils influenced by the topographical factor in Savanna area. It was carried out along three toposequences in Gogbala area of Korhogo Department, Northern Côte d'Ivoire. Soil samples were collected at each topographic unit, namely, upper slope positions, mid slope positions and bottom slope positions. Samples collected were air-dried, crushed and sieved in a 2 mm sieve preparatory to laboratory analysis. The results showed that Cambisols are the dominant soils in the study area; these are characteristic soils of reddish brown (2.5YR 4/6) to yellowish brown (10YR 4/2) at the upper and mid slope positions, and grey (10YR 5/1) at the lower slope positions. These are well drained soils whose genesis is considered to have been predominantly influenced by climate in which they occur. The profiles are weak fine granular transformation and evident changes in soil structure, color and clay content. They are dominated by sandy loam textures. Organic matter and N, available P, Exchangeable Ca, Mg contents, CEC are in the range of low to medium values. The pH values of the samples are acid (pH < 6). Fertility is low. Therefore, to perform agricultural managements in Gogbala area, decision-makers should take into soil morphological and physico-chemical characteristics consideration, suggest the need of integrated nutrient management with addition of both organic and inorganic fertilizers in the land units.