The effect of regulated deficit irrigation on growth, yield, and berry quality of grapevines (cv. Sangiovese) grafted on rootstocks with different resistance to water deficit

The aim of this work was to investigate the effect of full irrigation (FI), pre-veraison water deficit (RDI 1), or post-veraison water deficit (RDI 2) on growth, yield, and berry quality in container-grown, mature vines of cv. Sangiovese grafted onto either 1103P or SO4 rootstock over two consecutive growing seasons. Deficit irrigation regimes significantly affected vine water status of both rootstocks before and after veraison. Trunk diameter (TD) increment was markedly affected when water was restricted early, but not in the post-veraison period. Deficit irrigation from fruit set to veraison inhibited vegetative growth (TD, canopy volume, and weight of pruned wood) more than that applied from veraison to harvest. Yield was unaffected by either irrigation or rootstock in both years. Irrigation had a marked effect on berry and juice quality: the RDI 1 treatment induced the highest berry anthocyanin concentration, and the lowest titratable acidity (TA), which, instead, increased in the RDI 2 treatment. RDI treatments did not modify berry dry weight, soluble solid content, TA, anthocyanins, and epicarp total phenols in vines on both rootstocks

Oil accumulation in intact olive fruits measured by near infrared spectroscopy-acousto-optically tunable filter

A field experiment was conducted to test the reliability of the near infrared spectroscopy (NIR) method to measure mesocarp oil content in vivo against nuclear magnetic resonance (NMR) determinations using three different olive cultivars at different stages of ripening. RESULTS: In PLS model carried out for the cultivar Arbequina the R2c (coefficients of determination in calibration) obtained was of 0.991, while the R2cv (coefficients of determination in cross-validation) of 0.979; for the cultivar Frantoio the indexes were respectively of 0.982 and 0.971, for the cultivar Leccino of 0.977 for R2c and 0.965 for R2cv. Finally, for the combined model (sum of the three varieties) those indexes were respectively equal to 0.921 and 0.903. The RPD ratio was insufficient for predictive model of cultivar Leccino only (1.98), whereas in other cases RPD ratios were completely sufficient, within the estimation range over 2.5 - 3 (2.61 in global model, and 4.23 in cultivar Frantoio), or describing a great capacity with values greater than 5 as in the case of the cultivar Arbequina (9.58). CONCLUSION: The NIR proved a novel, rapid, reliable method to monitor the oil accumulation process in intact olive fruits in the field. The innovative approach of coupling NIR and NMR technologies opens new scenarios for determining the optimal time for harvesting olive trees to obtain maximum oil production

Componenti della produttività ed effetto del-l’irrigazione sulla cascola pre-raccolta dei frutti in olivi della cultivar Frantoio

Gli effetti dell’irrigazione sulla cascola pre-raccolta dei frutti e sulle componenti produttive dell’olivo sono stati valutati in un esperimento condotto in un oliveto (Olea europaea L., cv Frantoio) intensivo di 6 anni di età. La piena restituzione del fabbisogno idrico dell’albero (PI) durante tutto il periodo irriguo è stata confrontata con un’ir-rigazione di soccorso (IS). Settimanalmente è stato misurato il peso fresco del frutto, l’indice di maturazione e il conte-nuto in olio nella polpa. La raccolta è stata effettuata 142 giorni dopo la piena fioritura (GDPF), ad eccezione di 3 alberi per tesi raccolti 185 GDPF. A partire da 106 GDPF, e per ogni settimana fino a 185 GDPF, sugli alberi selezionati per una raccolta tardiva è stata misurata la cascola dei frutti, distinta tra cascola fisiologica e causata da B. oleae. I frutti degli alberi IS hanno mostrato un minor peso fresco durante tutto il periodo irriguo (-24%) e un maggior indice di matu-razione alla raccolta di ottobre (+25%) rispetto agli alberi PI. Non sono emerse differenze significative tra le tesi in merito al contenuto in olio nella polpa. Le produzioni ad albero nella tesi PI sono state superiori di circa il 30%rispetto a quelle degli alberi IS. A partire da 163 GDPF, e fino alla seconda raccolta, le maggiori percentuali di casco-la sono state misurate sugli alberi sottoposti ad irrigazione di soccorso. Tale cascola, prevalentemente fisiologica, è imputabile al crescente livello di stress idrico subito dagli alberi in asciutto nel corso del periodo estivo. Al contrario, la piena irrigazione ha comportato un maggior livello di infestazione di B. oleae, stimata come % di frutti con foro d’uscita, sulle produzioni alla raccolta 142 GDPF. Considerando il regime irriguo e le perdite legate alla cascola, il periodo di raccolta utile per ottenere produzioni superiori al 90% della produzione massima stimata è stato compreso tra i 263 e i 298 e tra i 273 e i 295 GDPF per la tesi PI e IS, rispettivamente

Effect of different irrigation volumes during fruit development on quality of virgin olive oil of cv. Frantoio

An experiment was carried out in a high-density olive (Olea europaea L. cv. Frantoio) orchard to determine the effect of different irrigation regimes (full, deficit, complementary) on virgin olive oil (VOO) quality over three consecutive years. Irrigation had negligible effects on free acidity, peroxide value, and fatty acid composition of VOO, but strongly influenced its phenolic concentration. Trees with high water status yielded oils with lower concentrations of total phenols and O-diphenols with respect to oils from severely stressed trees. The concentrations of secoiridoids, like the dialdehydic form of decarboxymethyl elenolic acid linked to (3,4-dihydroxyphenyl)ethanol (3,4-DHPEA-EDA), the isomer of the oleuropein aglycon (3,4-DHPEA-EA) and the dialdehydic form of decarboxymethyl elenolic acid linked to (p-hydroxyphenyl) ethanol (p-HPEA-EDA), were lower in fully-irrigated trees than in trees under deficit irrigation or those that received complementary irrigation only. The concentrations of lignans (+)-1-acetoxipinoresinol and (+)-1-pinoresinol were unaffected by the irrigation regime. Volatile compounds, evaluated on the VOO head space, seemed to be more consistently influenced by the year rather than soil water availability

Soil ecosystem functions in a high-density olive orchard managed by different soil conservation practices

The long-term effects of two different soil management practices, natural grass cover (NC) and conservation tillage (CT), on soil functions (carbon sequestration, habitat for organisms, and water movement and retention) were determined in a high-density, mature olive orchard (Olea europaea L. cv. Frantoio) growing in a sandy loam soil (Typic Haploxeralf) in a Mediterranean environment. Ten years after the beginning of the different soil management, soil samples were collected at 0–10 and 10–20 cm depth and at two distances from the trunk, underneath the olive canopy (UC) and in the inter-row (IR). There were no differences in fruit yield, oil yield, and yield efficiency between the two soil management systems during the 2011–2013 period. CT negatively affected soil organic carbon pools (total and humified), but only at the IR position. The distance from the plant did not significantly influence soil structure and hydrological properties, while NC treatment increased water movement and retention. Tillage reduced the microarthropod abundance, in particular Collembola and eu-edaphic forms, which were the most sensitive groups to soil perturbation. We conclude that natural grass cover was more effective than conservation tillage in maintaining or improving elements of soil functionality

High-resolution imagery acquired from an unmanned platform to estimate biophysical and geometrical parameters of olive trees under different irrigation regimes

The experiments were conducted in a fully-productive olive orchard (cv. Frantoio) at the experimental farm of University of Pisa at Venturina (Italy) in 2015 to assess the ability of an unmanned aerial vehicle (UAV) equipped with RGB-NIR cameras to estimate leaf area index (LAI), tree height, canopy diameter and canopy volume of olive trees that were either irrigated or rainfed. Irrigated trees received water 4–5 days a week (1348 m3 ha-1), whereas the rainfed ones received a single irrigation of 19 m3 ha-1 to relieve the extreme stress. The flight altitude was 70 m above ground level (AGL), except for one flight (50 m AGL). The Normalized Difference Vegetation Index (NDVI) was calculated by means of the map algebra technique. Canopy volume, canopy height and diameter were obtained from the digital surface model (DSM) obtained through automatic aerial triangulation, bundle block adjustment and camera calibration methods. The NDVI estimated on the day of the year (DOY) 130 was linearly correlated with both LAI and leaf chlorophyll measured on the same date (R2 = 0.78 and 0.80, respectively). The correlation between the on ground measured canopy volumes and the ones by the UAV-RGB camera techniques yielded an R2 of 0.71–0.86. The monthly canopy volume increment estimated from UAV surveys between (DOY) 130 and 244 was highly correlated with the daily water stress integral of rainfed trees (R2 = 0.99). The effect of water stress on the seasonal pattern of canopy growth was detected by these techniques in correspondence of the maximum level of stress experienced by the rainfed trees. The highest level of accuracy (RMSE = 0.16 m) in canopy height estimation was obtained when the flight altitude was 50 m AGL, yielding an R2 value of 0.87 and an almost 1:1 ratio of measured versus estimated canopy height