EFFECT OF SAMPLE RE-SATURATION ON SOIL-WATER CHARACTERISTIC CURVE

Ícaro Vasconcelos Do Nascimento,Jaedson Cláudio Anunciato Mota,Raimundo Nonato De Assis Júnior,Thiago Leite De Alencar,Carlos Levi Anastácio Dos Santos

doi:10.1590/1983-21252018v31n221rc

Ícaro Vasconcelos Do Nascimento, Jaedson Cláudio Anunciato Mota + Show 3 more

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https://doi.org/10.1590/1983-21252018v31n221rc

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Journal: Revista Caatinga	Publication Date: Jun 1, 2018
Citations: 2	License type: cc-by

Affiliation: Universidade Federal do Ceará

Abstract

ABSTRACT Soil-water characteristic curve (SWCC) is an important tool for water management in irrigated agriculture. However, factors such as texture and structure of soils influence SWCC behavior. According to the literature, wetting and drying cycles alter SWCC. A similar process of re-saturation and drying occurs during SWCC obtainment under laboratory conditions. Based on the hypothesis that re-saturation process alters SWCC due to clay loss in the sample, this study aimed to obtain the SWCC, S index, and pore size distribution from samples submitted to re-saturation cycles, as well as from not re-saturated samples but under higher matric potentials (-2, -4, -6, -8, and -10 kPa). For this, disturbed and undisturbed soil samples, collected from the A (sandy texture) and Btg (sandy clay loam texture) horizons of a Argissolo Acizentado, were used. After obtaining SWCC, each air-dried soil sample was submitted to particle size and clay dispersed in water analyses to verify whether the soil lost clay. The experimental design was a completely randomized design with two methods of SWCC constructing (with and without re-saturation) and eight replications. The re-saturation process generates a loss of clay in the sample, not causing significant changes in SWCC considering the assessed textural soil classes. In addition, sandy soil samples are more sensitive to changes in pore size distribution when submitted to re-saturation.

Highlights

The efficient use of water resources is reinforced by the possibility of scarcity in the future (JERÓNIMO; HENRIQUES; CARVALHO, 2015)
Adequate water management practices are essential for the sustainability of irrigated agriculture
This study aimed to obtain, for the two textural classes, the soil-water characteristic curve (SWCC), S index (DEXTER, 2004), and pore size distribution from samples submitted to re-saturation cycles, as well as from not re-saturated samples but under higher matric potentials (−2, −4, −6, −8, and −10 kPa) of SWCC

Summary

Introduction

The efficient use of water resources is reinforced by the possibility of scarcity in the future (JERÓNIMO; HENRIQUES; CARVALHO, 2015). The relationship between soil potential (φm) and volumetric soil water content (θ) is important in describing water behavior (LUCAS et al, 2011), being essential for studies of soil-water relations (SILVA et al, 2006). This relationship can be expressed mathematically by θ = f (φm) or φm = f (θ) (ALMEIDA et al, 2015). The graphic representation of these functions is called soil-water characteristic curve (SWCC) (REICHARDT; TIMM, 2012) and assists in determining the available and current water content in the soil, as well as other basic variables to the proper irrigation management (COSTA; OLIVEIRA; KATO, 2008), indicating more appropriate agricultural production practices (MACHADO et al, 2008)

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