English

Dao D.,Assa A.,Girardin O.,Tschannen A.,Nindjin C.,Bakayoko S.,Soro D.

doi:10.5897/ajest09.072

Abstract

This study examined the A and B horizons of deep, developed and moderately unsaturated sandy ferrallitic soils amended with cattle and poultry manures under cassava (Manihot esculenta Crantz) cultivation. Therefore, a plot experiment was carried out by using a randomized complete blocks design in 4 replications and fields treatments which included unfertilized (control) and one dose (10 t/ha) of both manures. The study of the different fractions of animal manures showed that the poultry had the greatest content of C (organic carbon), N (nitrogen), P (phosphorus), K (potassium), Ca (calcium) and C:N ratio (p < 0.01). However, the value of Mg (magnesium) in the studied manures was not significantly different (p < 0.01). The manure treatment significantly increased the soil organic matter contents from 0.46 to 2.8 and 1.1% respectively with poultry and cattle manures (p < 0.01). Organic fertilizer significantly increased the cation exchange capacity from 1.7 to 12.75 and 3.8 me:100 g and the bases saturation content from 47 to 80 and to 76% respectively with the poultry and cattle manures (p < 0.01). The organic fertilizer showed significant effect on earthworms populationsHyperiodrilus africanus (Oligochaeta, Eudrilidae) in the soil, with 128 and 85% respectively about the poultry and cattle manures compared to the control (p < 0.01). Key words: Cattle manure, poultry manure, cassava, organic matter, cation exchange capacity, bases saturation content.

Highlights

Cassava is grown in every agroecological zone of the Côte d’Ivoire and it is the major food crop after yam
The decline in soil productivity as a result of continuous cultivation in sub-Saharan Africa has been identified as a major cause of food insecurity and poverty and crop yields continue to decline on smallholder farmers fields and there is a huge gap between potential crop yields and actual crop yields (Yeboah et al, 2009).The degradation induces a significant decrease of the soil organic matter content which modifies the nitrogen cycle (Ouattara et al, 2006)
The soil constraints that reduce the yields of cassava such as soil alkalinity and salinity, exchangeable aluminium (Al), high pH above 8.0 and exchangeable sodium (Na) percentage of above 2.5% have been outlined by Cock and Howeler (1978)

Summary

Introduction

Cassava is grown in every agroecological zone of the Côte d’Ivoire and it is the major food crop after yam. Côte d'Ivoire is a country with high density of population (48 inh./km2) and a high population increase rate of 3.8%/year (Institute National de la Statistique, 1998).This situation causes a strong pressure on the cultivable lands, and considerably reduces the fallow duration. This led to an impoverishment of the soil because of their consecutive overexploitation which is combined to Bakayoko et al 191 bush fires actions (Carsky, 2003). In Côte d’Ivoire, the low levels of organic matter and total nitrogen (N) were the major soil constraints identified (Asadu et al, 1998). The soil constraints that reduce the yields of cassava such as soil alkalinity and salinity, exchangeable aluminium (Al), high pH above 8.0 and exchangeable sodium (Na) percentage of above 2.5% have been outlined by Cock and Howeler (1978)

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