Soil respiration in a traditional olive grove in the southeast of Spain

Abstract

<p>Olive groves occupy a large area in the Mediterranean and their management has repercussions on the carbon cycle in this region.  Weed suppression is the most common management in this crop, but its implications for soil respiration (R<sub>soil</sub>) are not well estimated due to the lack in continuous R<sub>soil</sub> measurements. In this research we present a full year of R<sub>soil</sub> in an irrigated olive grove in which a glyphosate-based herbicide was applied to prevent spontaneous weeds (conventional management). For that, an automatic multi-chamber R<sub>soil</sub> system was used (LI-8100 + LI-8150 with 6 chambers, Li-Cor). In addition, soil temperature (T<sub>soil</sub>) and soil water content (SWC) were measured next to each chamber. To study the influence of olive trees on R<sub>soil</sub>, 3 chambers were placed near the olive trunk and another 3 in the middle of the alleys.</p> <p>Results show seasonal and spatial variability, with higher R<sub>soil</sub> in warm months and lower R<sub>soil</sub> in cold months. Also, R<sub>soil</sub> near the trunk was always larger than in the alleys. The spatial difference increased in the cold months. Diurnal variability was observed with higher R<sub>soil</sub> as the soil temperature increased in the alleys, but this was not observed near the trunks. Under the canopy, a decrease in the R<sub>soil</sub> is observed as the VPD increases, suggesting a major contribution of autotrophic respiration under the canopy. In addition, there is no positive and negative relationship with temperature and SWC under the canopy, while in the alleys, a strong hysteresis occurs in some periods. Finally, rain events were followed by R<sub>soil</sub> peaks. However, low intensity and short duration rain pulses did not manifest on the ground under the olive canopy, so interception is inhibiting this process in part of the agrosystem.</p> <p>This work was supported by the projects PID2020-117825GB-C21 & PID2020-117825GB-C22 (INTEGRATYON3), B-RNM-60-UGR20 (OLEAGEIs) and P18-RT-3629 (ICAERSA) including European Union ERDF funds.</p>

Study of Photosynthesis-Light Response Curves in <em>Olea europaea </em>L. subsp <em>europaea </em>Cultivars and Their Adaptation to Climate Change

“…In Spain, more than 250 olive cultivars have been reported [5,6]. The most abundant in the olive groves of the Iberian Penisula is Picual, typical of the fields of Jaén, with more than 66 million olive trees in this province, and it is also a predominant cultivar in Southeastern Andalusia and part of the Centre of Spain.…”

“…Few studies exist to date in this regard on Olea europaea. Aranda Barranco et al, (2020) [5,6] studied the capacity to sequester carbon in two Spanish olive groves whose management differed in the vegetation cover of each of them. In the first case, the field did not have such plant groundcovers compared to the second olive grove, which did.…”