A study on mineral fertilization of soils was carried out for two years in three cocoa farms in the Nawa region of south-western Côte d’Ivoire. The aim of this study was to evaluate the effects of mineral fertilizers on soil macrofauna. The experimental design was Fisher block with four treatment with three repetitions. The treatments were control without fertilizer (T0), NPK 0-23-19 fertilizer (T1), NPK 0-15-15 + 17 CaO + 5 MgO + 1 B2O3 + 0.5 Zn (T2) and NPK 4-10-10 + 19 CaO + 4 MgO + 0.8 B2O3 + 0.3 Zn (T3). Twelve soil monoliths were made per treatment and per site, to count the macrofauna of the soil. Each soil monolith was subdivided into three strata 0-10 cm, 10-20 cm and 20-30 cm. The organisms were counted and classified into functional groups. The abundance, species richness and diversity indices of Shannon-weaver and Piélou were determined. The analysis of variance of the numbers of individuals in the macrofauna did not show a significant difference between the treatments on different strata of the monoliths during the second year of the trial. However, during the first year, all the treatments with fertilizer in the 0-10 cm stratum had a more abundant macrofauna than that of the control without fertilizer at Soubré and Mayo. Multivariate analyses (AFC) showed links between functional groups of organisms and treatments. Myriapods and earthworms were linked to the T2 and T3 treatments, microarthropods to T1 and other organisms to T0. As for macrofauna diversity, the highest value of species richness (7 species), Shannon-weaver (2) and Piélou (1) indices were found in the fertilized treatments. Mineral fertilizers thus presented better conditions for the expansion of macrofauna. A reasoned application of mineral fertilizers creates a favourable living environment for certain soil organisms.

Ivorian cocoa production, which still remains the driving force of the national economy today, despite the increasingly pronounced diversification of the State's resources, has long benefited from relatively favorable climatic conditions. However, since the 1970s, recurrent disruptions in key rainfall indicators for cocoa production have posed significant risks to the yields and incomes of many Ivorians who depend directly or indirectly on the agronomic performance of this speculation. Using a methodological approach based on descriptive statistical analysis, this study provides an understanding of the evolution of the main climatic factors involved in cocoa production in the Central West, which is one of the country's natural cocoa production basins. To carry out this task, daily rainfall data from Divo and Gagnoa, covering the period 1946-2015, were collected and processed. The results of the various statistical analyses indicate that the seasonal and intra-seasonal rainfall indicators in Gagnoa and Divo are generally declining after the break-up years detected in 1972 in Divo and 1966 in Gagnoa. After the breaks, the Useful Rainy Season (URS) starts later and the ends are earlier than before, which results in a shortening of the length of the URS and a reduction in the intra-seasonal rainfall totals of the two localities. Conversely, the maximum dry sequences during the URS show a slight increase after the break-up dates. The station of Gagnoa was less affected by the rainfall recession than that of Divo where the downward trend in seasonal and intra-seasonal rainfall events is more severe. This makes the Gagnoa region the one with the best rainfall capacities for cocoa production in the study area.

Aims: To understand the role of the interannual variability of cumulative rainfall and maximum dry sequences in cocoa production in the Centre-Ouest, one of the cocoa basins in Côte d'Ivoire, in order to propose technical routes more adapted to current rainfall conditions. Study Design: Collection, analysis and processing of daily rainfall data collected by the rain gauges at Divo and Gagnoa stations. Location and Duration of Studies: Divo Cocoa Research Station of the National Center for Agricultural Research, between January 2017 and June 2019. Methodology: The rainfall regime of each locality was determined to assess the impact of rainfall changes on the seasonality of rainfall. The interannual variability of rainfall was studied from the reduced centred rainfall indices. The break years in the time series were detected at both stations from the Khrono Stat software. The interannual cumulative rainfall were analysed for each station and compared to the minimum threshold allowed for cocoa trees. The means of the maximum interannual dry sequences and their probabilities of occurrence were determined using the agrometeorological software called Instat + Version 3.37. Results: The rainfall regime in the area studied (west-central Côte d'Ivoire) has not been modified by the post-rupture rainfall recession as is the case in other parts of the country; it remains a bimodal system characterized by two rainy seasons and two dries during the year. The Divo and Gagnoa regions have been facing a general recession in rainfall since 1966 in Gagnoa and 1972 in Divo. However, the locality of Gagnoa has experienced an increase in rainfall since 2000. Most of the rupture detection tests identified rainfall rupture dates identical to those indicated by the interannual variability highlighted by the rainfall indices. In Gagnoa and Divo, the interannual cumulative rainfalls after the years of rainfall break are reduced compared to those before these rainfall accidents. This situation has led to an increase in the maximum interannual dry sequences in the departments studied. Conclusion: Local climate change has created difficult rainfall conditions after years of rainfall break for cocoa trees as their water needs are increasingly reduced, especially in Divo in Lôh-Djiboua where the downward trend in rainfall has been continuous since 1972. In Gagnoa since the beginning of this century, there has been a new wet period that allows rainfall to adequately meet the cocoa tree's water requirements.

The sustainability of cocoa farming is a major concern for Côte d'Ivoire. Extensive and "full sun" cropping systems need to be reviewed. Against this backdrop, a study was carried out in the south-west of the country (Soubré and Méagui), a major production zone, with the aim of assessing the impact of traditional agroforestry systems on soil fertility. Twenty-seven cocoa farms in the three sectors were visited. To assess the impact of cocoa-based agroforestry systems on soil chemical parameters, four criteria guided the choice of plots. These were mid-slope plots, 25 to 35 years old, unfertilized and denser in associated trees. Soil samples were taken from the 0-20 cm horizon. Organic carbon, total nitrogen, assimilable phosphorus, exchangeable bases (Ca, Mg, K and Na), cation exchange capacity and saturation rate were measured. The results show that traditional cocoa-based agroforestry systems have not impoverished the soil. In fact, chemical fertility in these plots respects the needs of cocoa trees. However, the study did not show an increase in soil organic matter due to the fall of leaves from associated trees. These results will enable the use of traditional agroforestry systems without fear of soil impoverishment due to any competition between cocoa trees and associated trees.