Measuring and Modelling Soil Evaporation in an Irrigated Olive Orchard to Improve Water Management

Luca Tezza,Melanie Häusler,Nuno Conceição,Maria Isabel Ferreira

doi:10.3390/w11122529

Abstract

The aim of this study was to estimate soil evaporation (Es) in an intensive olive orchard. Measurements of Es were performed for 19 days using microlysimeters, during summers 2010, 2011 and 2012 in southeast Portugal. In order to relate each area type to radiation transmissivity, ground cover measurements were performed over the years. These data were used to calibrate and validate an empirical model for Es estimation. Measured daily average Es was 0.55 ± 0.14 mm; the model estimated 0.53 ± 0.18 mm for the same days, with a determination coefficient of 0.94. This corresponds to 9% of the reference evapotranspiration, representing well the overall values estimated for the summer, except for days after rain. Regarding the wet area, measured Es for the validation data set was 2.42 L/(m2 of wet area), the estimated was 2.49 L/(m2 of wet area). Measured average Es in dry area (validation data set) was 0.42 L/(m2 of dry area), estimated Es was 0.43 L/(m2 of dry area). The large exposed dry area had a significant contribution to evaporation. On average, estimated Es during a typical Mediterranean summer was 10% of reference evapotranspiration, representing 30% of transpiration and 23% of evapotranspiration.

Highlights

In regions where summer water scarcity will not allow intensive agriculture, irrigation is essential to maintain high and constant levels of production
Partial tree(example coveragein ofFigure the under-tree resulted the in high spatial variability of irradiance the
Based on be used from the crop and users aim to reduce this component by good practices such as localized these data, they modeled Es considering that, from February to irrigation

Summary

Introduction

In regions where summer water scarcity will not allow intensive agriculture, irrigation is essential to maintain high and constant levels of production. For this reason, there was a significant worldwide expansion of irrigated areas at the end of the 60s, playing a primary role in increasing food production. Of renewable water resources, a 10% increase in global water use efficiency by the agricultural sector would allow 40% more water for domestic and industrial use [3]. Improving agriculture water use efficiency requests assessing the crop water requirements, allowing optimization of scheduling strategies that, together with the use of more efficient irrigation

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Conclusion