## 3 Results and Discussion
### Analytical Parameters of Olive Oil Quality  
In general, no important differences were found for the quality parameters (Table 2); this was expected because all samples were obtained from freshly harvested olives without significant defects. However, in the 2018 season, the peroxide index was higher in the control treatment, T\({}_{0}\) (11.8 meq O\({}_{2}\) kg\({}^{-1}\)) compared to that observed in the stressed samples.  
\begin{table}
\begin{tabular}{l c c c c c c} \hline \hline \multirow{2}{*}{**Factor**} & **Min \(\Psi_{stem}\)** & **SI Total** & **SI Phase II** & **SI Phase III** & **AW** & **Olive Oil** \\  & **(MPa)** & **(MPa Day\({}^{-1}\))** & **(MPa Day\({}^{-1}\))** & **(MPa Day\({}^{-1}\))** & **(L m\({}^{-2}\))** & **Production** \\  & & & & & & \\  & & & & & & \\  & & & & & & \\  & & & & & & \\ \hline \multicolumn{8}{c}{**ANOVA \({}^{\dagger}\)**} \\ \hline Season & n.s. & n.s. & n.s. & n.s. & *** & n.s. \\ \multicolumn{8}{c}{**Inrigation**} \\ \multicolumn{8}{c}{**season \(\times\) Inrigation**} \\ \hline \multicolumn{8}{c}{**Tukey Multiple Range Test \({}^{\ddagger}\)**} \\ \hline Season & & & & & \\  & 2018 & \(-\)3.35 & 76.0 & 54.6 & 16.9 & 304 b & 2198 \\  & 2019 & \(-\)3.47 & 103 & 71.9 & 30.2 & 484 a & 2025 \\ \multicolumn{8}{c}{**Inrigation**} \\ \multicolumn{8}{c}{**T\({}_{0}\)**} & \(-\)1.88 a & 9.53 c & 9.25 c & 0.17 b & 753 a & 2192 \\  & \(-\)2.94 ab & 46.3 bc & 43.24 bc & 2.09 b & 390 b & 2162 \\  & \(-\)4.96 c & 179 a & 127 a & 48.8 a & 221 c & 2035 \\  & \(-\)3.87 bc & 123 ab & 73.2 ab & 43.9 a & 212 c & 2056 \\ Season \(\times\) Inrigation** & & & & & \\  & 2018 & \(\times\)**T\({}_{0}\)** & \(-\)2.21 ab & 18.4 b & 18.2 b & 0.00 b & 533 b & 2348 \\  & 2018 & \(\times\)**T\({}_{1}\)** & \(-\)2.74 abc & 40.7 b & 38.7 b & 0.48 b & 334 cd & 2169 \\  & 2018 & \(\times\)**T\({}_{2}\)** & \(-\)4.71 bc & 140 ab & 104 ab & 30.0 b & 173 e & 2240 \\  & 2018 & \(\times\)**T\({}_{3}\)** & \(-\)3.75 abc & 105 ab & 57.6 ab & 37.1 ab & 175 e & 2034 \\  & 2019 & \(\times\)**T\({}_{0}\)** & \(-\)1.54 a & 0.681 b & 0.338 b & 0.34 b & 972 a & 2037 \\  & 2019 & \(\times\)**T\({}_{1}\)** & \(-\)3.15 abc & 51.8 b & 47.8 ab & 3.70 b & 446 bc & 2154 \\  & 2019 & \(\times\)**T\({}_{2}\)** & \(-\)5.21 c & 219 a & 151 a & 66.0 a & 269 de & 1831 \\  & 2019 & \(\times\)**T\({}_{3}\)** & \(-\)3.99 abc & 141 ab & 88.9 ab & 50.7 ab & 248 de & 2077 \\ \hline \multicolumn{8}{c}{\({}^{\dagger}\) n.s. = not significant at \(p>\) 0.05, ** and *** significant at \(p<\) 0.01 and \(p<\) 0.005; \({}^{\ddagger}\) Values followed by the same letter, within the same column and factor, were not significantly different (\(p>\) 0.05), according to the [PERSON]’s least significant difference test.} \\ \end{tabular}
\end{table}
Table 1: Effect of the season (2018 and 2019) and irrigation treatment (T\({}_{0}\), T\({}_{1}\), T\({}_{2}\) and T\({}_{3}\)) on minimum stem water potential (min \(\Psi_{stem}\)), water stress integral (\(SI\), MPa day\({}^{-1}\)), applied water (\(AW\), L m\({}^{-2}\)) and olive oil production in each deficit irrigation treatment during pit hardening in a super-high-density ‘Arbequina’ olive tree orchard.  
Similar effects have been previously observed, with lower peroxide index values in samples from water-stressed olive trees [28].  
A similar behavior to that previously described for the peroxide index was also found for the acidity index in the 2018 season, where the T\({}_{0}\) value (0.42% oleic acid) was higher than those found for the rest of treatments (mean of 0.18%).  
All samples under study were classified as extra virgin olive oil according to the Official Commercial Classification stablished by International Olive Oil Council [27]. This way, it can be concluded that deficit irrigation treatments did not reduce the quality of the olive oil; similar results were previously reported by [PERSON] and [PERSON] [29] for the same olive variety, in Toledo (central Spain), despite the water reduction levels.