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

Oswaldo Palma Lopes Sobrinho,Rodrigo Almeida Santana,Rafael Silva Firmo,Gerlange Soares Da Silva,Francisco Adriano De Carvalho Pereira,Jucicléia Soares Da Silva

doi:10.1590/1983-21252019v32n323rc

Abstract

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.

Highlights

IntroductionThe soils of Coastal Tablelands, well structured, cohesive layer present near their surface (0.30–0.70 m deep), which in turn can impair the production of various agricultural crops because of the high resistance soil penetration of roots when dry (RAMOS et al, 2013)
Agricultural productivity has intensified in geo-environmental units of the Coastal Tablelands due to its agricultural potential (LIRA et al, 2016) and the increase of irrigation techniques, which in turn opens up space for the production of cocoa
The soils of Coastal Tablelands, well structured, cohesive layer present near their surface (0.30–0.70 m deep), which in turn can impair the production of various agricultural crops because of the high resistance soil penetration of roots when dry (RAMOS et al, 2013)

Summary

Introduction

The soils of Coastal Tablelands, well structured, cohesive layer present near their surface (0.30–0.70 m deep), which in turn can impair the production of various agricultural crops because of the high resistance soil penetration of roots when dry (RAMOS et al, 2013). The cohesive character, by directly influence the development of the root system, ends up limiting the extraction of water and nutrients by plants and reduces soil aeration (REZENDE et al, 2002) This can be a limiting factor for growing cocoa plants that concentrate the effective root system in the first 0.30 m deep soil layers and density on the surface that modifies the soil water dynamic may compromise the growth of plants. Since the K0 represents the ease with which the soil transmits water, it is influenced by the physical properties of the soil (GONÇALVES; LIBARDI, 2013)

Methods

Results

Conclusion