Study on Sprinkler Irrigation and Soil Tillage Practices in Sugarcane Plantations as Influenced by Soil Texture and Water Storage in Northern Ivory Coast

Objective: Soil survey investigations were carried out in Ferke 1 as well as Ferke 2 sugar mills of northern Ivory Coast to determine soil texture and water storage capacity for sprinkler irrigation and tillage management. The sugarcane farmlands being investigated since 2008 in both locations reached 95 % of the total area under cultivation (11,400 ha). Methodology and results: Soil sampling was achieved after harvest or prior to re-plantation in 5 different spots along 2 transects over 30 cm depth, in every farmland as to get an average soil sample of 1.5-2 kg. Soil physical properties like texture and water retention curves were determined locally in the sugar company’s soil laboratory. The results showed that majority of farmland soils investigated was coarsetextured for about 64 % in Ferke 1 and 85 % in Ferke 2, with a lower to medium water storage capacity (7089 mm) over 60 cm depth which corresponds to a readily available moisture less than 60 mm. These light soils were much suitable for the practice of minimum tillage which importantly contributes to reduce sugarcane production costs. The other textural categories such as sandy-clay or clay-loam, rather well balanced and less suitable for the practice of reduced tillage without pre-watering, gave medium to high total available moisture (90-110 mm) and therefore a maximum irrigation application rate (or readily available moisture) of 60-70 mm. Except for the sugarcane plant crop, no significant difference in cane yields resulting from tillage practices was observed over four consecutive cropping seasons. The yield decline from plant cane to first ratoon is very high under conventional tillage (-16 t/ha) compared with the reduced tillage (+3 t/ha). Even higher cane yield was obtained on the second ratoon (89 t/ha) compared with the conventional tillage (83 t/ha). Conclusion and application: Better knowledge of soil texture as well as total available moisture resulted in improved practices of sprinkler irrigation and soil tillage in Ivorian sugarcane plantations. Key word: particle size distribution, physical property, water retention, available moisture, reduced tillage, irrigation management