Spring deficit irrigation in olive (cv. Genovesa) growing under arid continental climate: Effects on vegetative growth and productive parameters

PIERANTOZZI, P.; TORRES, M.; TIVANI, M.; CONTRERAS, C.; GENTILI, L.; PARERA, C.; MAESTRI, D.

AGRICULTURAL WATER MANAGEMENT

ELSEVIER SCIENCE BV

Año: 2020 vol. 238

0378-3774

This study was aimed to evaluate the effect of regulated deficit irrigation (RDI), applied from mid-spring to earlysummer, on physiological parameters, vegetative growth and productivity in an intensive hedgerow oliveorchard located in a non-traditional (marked winter-spring water-deficit) olive growing region. The experimentswere carried out during three crop seasons by using four years old (7 m × 3.5 m) ?Genovesa? olive trees. ThreeRDI treatments (T25, T50 and T75) were applied as a percentage of crop evapotranspiration (25, 50 and 75%ETc, respectively) during the period from fruit set to pit hardening. Also, a control treatment was irrigated at100% ETc during the whole crop season. Under the analyzed environmental conditions, stomatal conductancewas less sensitive in young leaves than in mature leaves against changes in water availability. This fact should beconsidered when being used as benchmarks in olives trees submitted to water deprivation during periods withmarked water constraint. Regarding vegetative parameters, significant reductions in apical vegetative shootgrowth, trunk cross-sectional area and canopy volume were found in less irrigated treatments (T25 and T50)with respect to most irrigated ones (T75 and T100). Moreover, the strongest effects of deficit irrigation wereobserved when pruning was applied at the end of the second crop season evaluated. Both fruit and oil yields werebarely affected by water availability. Although in the first crop season evaluated the fruit yield was greater in thefull-irrigation treatment ? which could be due to the age of the olive trees -, at the end of the whole experimentalperiod (three crop years) the mean values from this yield component did not present significant differencesamong all irrigation treatments. Similarly, water availability did not affect oil yield (kg/ha); no significantdifferences were found among irrigation treatments in any of the crop seasons analyzed. The effects of wateravailability on productive parameters were more evident when analyzed as an estimated productive response;the total water productivity, calculated on both fruit weight and oil weight bases, gave the highest values in themost restrictive irrigation treatment. Overall, findings from this study could be of interest for olive cultivation inregions with dry spring period and for intensive hedgerow orchards suited to over-row harvesters. Imposingwater restriction during this period could be suitable for achieving sustainable fruit and oil productivity whilesaving considerable amount of irrigation water.