Effects of Irrigation and Tree Spacing on Soil and Air Temperature Profiles of Olive Orchards

Abstract

Changes on the climate of the boundary layer occur when a vegetation cover above a bare soil is introduced, namely on temperatures and humidity profiles, above and under soil surface. Since air and soil temperatures affect crop growth and development and also soil moisture, they have been used as driving variables in numerous crop growth and development models as well as in those referred to soil mineralization, evaporation, transpiration, etc. The aim of this work was to evaluate (a) the soil thermal behavior in two olive orchards (Olea europaea sp. europaea), both grown on soils with little profile development (Regosol and Cambisol) and subject to drip irrigation but with different spacing between trees, and (b) the air thermal profile over olive rows. Experiments were performed from April to June 2012 in Southern Portugal. Soil and air temperatures were measured by thermocouples. The two orchards changed spatial distribution of soil surface temperature, soil temperature profiles and air temperature within the canopy, either on a daily or hourly basis. Olive tree spacing and irrigation affected both the soil thermal behavior and air thermal profiles. Tree spacing affected the horizontal gradients established along the interrows (intensity and rhythm). Irrigation reduced hourly and daily mean soil surface temperatures and daily thermal amplitudes of both profiles. Differences were also found on damping depths of the thermal wave estimated for the driest and the wettest profiles. Along the row, the effect of shading seems to overlap that of irrigation in a hourly basis.

The role of soil temperature in mediterranean vineyards in a climate change context

“…However, Mediterranean viticulture is highly vulnerable to climate change (Costa et al, 2016;Fraga et al, 2016;Santos et al, 2020;Xyrafis et al, 2022), especially to the combination of longer warmer and drier periods. The same occurs for other Mediterranean perennial crops, such as olive groves and almond orchards (Andrade et al, 2014;Garcia-Tejero et al, 2018;Fraga et al, 2021).…”

“…Sustainable water and soil management are the core of several sustainability programs in the wine sector ( Costa et al., 2022 ) and other perennial woody crops, such as olive groves and almond orchards ( Andrade et al., 2014 ; Garcia-Tejero et al., 2018 ; Fraga et al., 2021 ). More sustainable practices related to soil management can help to alleviate the harmful effects of more extreme drought and heat events due to climate change.…”

“…More sustainable practices related to soil management can help to alleviate the harmful effects of more extreme drought and heat events due to climate change. This is an increasingly important issue for Mediterranean viticulture and must combine effective soil and canopy management strategies ( Figure 4 ), together with more efficient use of irrigation water and better-adapted varieties/rootstock combinations ( Andrade et al., 2014 ; Costa et al., 2016 ; Cataldo et al., 2021 ; Naulleau et al., 2021 ).…”

“…Irrigation is probably the most important and effective short-term adaptation strategy to face the impacts of climate change in Mediterranean vineyards, attending to its high effectiveness in moderating thermal microclimatic extremes at both soil, plant and atmosphere levels ( Andrade et al., 2014 ; Costa et al., 2016 ) (see Figures 3 , 5 ). Watering and higher soil moisture promote transpiration and the related evaporative cooling in plants, and also favor soil water evaporation ( Figures 1 , 3 ).…”