Climatic and Soil Water Balances for the Melon Crop

Jaedson Cláudio Anunciato Mota,Alcione Guimarães Freire,Raimundo Nonato Assis Júnior,Thiago Leite Alencar,Márcio Godofrêdo Rocha Lobato,Alexsandro Santos Brito,Juarez Cassiano Lima Júnior,Paulo Leonel Libardi

doi:10.5539/jas.v10n2p116

Abstract

The correct estimate of the water requirements of a crop, besides favoring its full development, also allows the rational use of water. In this context, this study aimed to evaluate water balance in the soil and estimated through climatic methods for the melon crop. Field water balance was daily determined along a period of 70 days. Climatic water balance was determined based on the reference evapotranspiration estimated by the methods of Penman-Monteith, Thornthwaite and Hargreaves-Samani. It was concluded that climatic methods do not estimate correctly water storage in the soil and, consequently, also the balance. Therefore, they should not substitute the soil water balance method to determine these variables. The water management for the melon crop based on evapotranspiration estimated through climatic methods results in overestimation of the water depth to be applied in the soil, in the initial growth stage, and underestimation in the periods of highest water demand.

Highlights

Irrigation is essential to meet the water requirements of the plants, especially in regions like Northeast Brazil
The present study considered the hypothesis that the soil water balance, in situ, for representing the actual conditions of the relationships in the soil-plant-atmosphere system, should not be substituted by the climatic water balance in the estimate of water requirement by the melon crop in the Brazilian semi-arid region
This study aimed to evaluate the water balances for the melon crop at field and estimated by the methods of Thornthwaite, Penman-Monteith, Hargreaves-Samani and Hargreaves-Samani with parameters adjusted to the local conditions (H-Sadj)

Summary

Introduction

Irrigation is essential to meet the water requirements of the plants, especially in regions like Northeast Brazil. In regions where the scarcity of water resources prevails in most of the time, special care must be taken with respect to water use and management, since it is a limiting factor in the production of agricultural crops (Libardi et al, 2015) This way, the measurement of the water requirement of a crop should be made, always when possible, based on parameters obtained in situ (Libardi et al, 2015), because they control the availability of water to plants (Hartmann et al, 2012). The soil water balance equation is not always used because of the difficulty of obtaining its components (Ghiberto et al, 2011), since it requires detailed information about the hydraulic soil properties (Ma et al, 2013; Campos et al, 2016). Climatic water balance has been used because its parameters can be obtained, since it utilizes data of climatic temporal series

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