SPATIAL VARIABILITY OF THE SATURATED HYDRAULIC CONDUCTIVITY OF SOIL IN COCOA FARMING IN RECÔNCAVO BAIANO

Abstract

Irrigated cocoa cultivation opened the way for production in Coastal Tablelands soils. However, in this region, the cohesive layer formed near the surface can be a limiting factor for production. The knowledge of physical soil water attributes enables the efficient irrigation management of cohesive soils. This study characterized and modeled the spatial variability of saturated hydraulic conductivity (K₀) in a Distrocoeso Oxisoil of the Recôncavo Baiano Coastal Tablelands. The soil sampling was performed as undeformed structures from 50 spaced points in an 8.0 to 8.0 m area, at three different depths in the experimental area of the Federal University of Bahia Recôncavo in the Cruz das Almas–BA cultivated with cocoa (‘CCN 51’). In the laboratory, K₀ was determined by permeameter method constant load, and the pore size distribution was determined using the voltage table and the soil density (Ds). Data were analyzed using descriptive statistics and geostatistics. On average, the K₀ values were 40.41, 26.49, and 37.82 mm^-1 h^-1 at the depths from 0.0–0.15 m, 0.15–0.30, and 0.30–0.45 m. The Gaussian model was the best fit to the K₀ data set. For soil class, the K₀ showed a strong spatial dependence due to their relationship with the physical properties of the soil, its use, and handling. Since an important attribute for the delimitation of homogeneous areas for specific site management purposes as well be considered.