Abstract Model Greensys2007 - International Conference of ...

Influence on Vine Production of Innovative Covering Plastic FilmsGiuliano Vox 1* , Evelia Schettini 1 , Giacomo Scarascia Mugnozza 1 ,Laura de Palma 2 , Luigi Tarricone 3 , Giovanni Gentilesco 31 Department of Agricultural and Environmental Science - DISAAT, University of Bari,via Amendola 165/A, 70126 Bari, Italy2 Department of Agro-Environmental Sciences, Chemistry and Plant Protection,University of Foggia, Via Napoli 25, 71100 Foggia, Italy3 Unità di ricerca per l’uva da tavola e la vitivinicoltura in ambiente mediterraneo, CRA-UTV,Via Casamassima 148, 70010 Turi, Bari, Italy*Corresponding author e-mail: giulius.vox@agr.uniba.itAbstractTwo commercial films, coded “YELLOW” and “NEUTRAL”, and one experimental film, coded“BASF” (provided by BASF Italia Srl), were tested in a vineyard located in Southern Italy(Castellaneta Marina, Taranto, Italy), during 2011, to assess their influence on the productivecharacteristic of a seedless grapevine variety. The vineyard was conducted applying theviticultural practices normally adopted for seedless varieties in the geographical area andwas drip-irrigated at about 50% of the full evapotranspiration. The radiometric properties ofthe films were evaluated by means of laboratory tests. In the field, the main microclimaticparameters were recorded: photosynthetic photon flux, air relative humidity and temperature.The main parameters of vine ecophysiological leaf functioning were also measured. Atharvest, the vine productivity and the grape quality were assessed. The radiometric testsshowed that the PAR total transmissivity coefficient was 86.3% for the “BASF” film, 81.8% forthe “NEUTRAL” film and 86.0 % for the “YELLOW”. By analyzing the vine production, grapeyield, berry and cluster weight were found higher under the “BASF” film than under the othertwo types of plastic covers.Key words: radiometric properties, solar radiation, table grapes, leaf functioning1. IntroductionPlastic films are used to cover vineyard in order to protect vines and grapes from externalweather conditions, such as rain, hail, spring frost, wind and snow. Plastic covering materialsincrease the internal air temperature around the vine by allowing solar radiation passingthrough whilst reducing the energetic radiative and convective losses (Papadakis et al.,2000). The thermal effect of a covering is connected to the radiometric properties of the film;for agronomical purposes a covering film must allow a high transmission of thephotosynthetically active radiation (PAR) and a low transmission of long wave infraredradiation (LWIR). Covering films may advance the ripening of table grapes, improve fruitquality parameters, obtain a more uniform grape skin color and a suitable sugar content. Thecover management and the radiometric properties of the plastic films influence grape yield,precocity and quality (de Palma et al., 1999; Novello et al., 2000; Tarricone, 2003).Table grape varieties need irrigation water supply in order to get a satisfying level ofproductivity and bunch quality; nevertheless, a mild water deficit, e.g. 60-80% of fullevapotranspiration (ET) for cv. Thompson Seedless, has proved to improve marketablegrape yield without penalizing sugar accumulation and berry weight, and a 50% deficitirrigationafter veraison has proved not to penalize berry size (Williams, 2000; Williams et al.,2010). There is a wide interest about deficit-irrigating in table grape vines because the globalclimate changes increase the probability that hot summers and long dry periods occur(Ezzahouani & Williams, 2007; Du et al., 2008).The aim of this paper is to evaluate the radiometric properties of different types of plasticfilms assessing their possible effects on vineyard microclimate, vine leaf functioning, yield

components and berry quality in cv. Sublima grown under cover and managed with deficitirrigation.2. Materials and MethodsThree polyethylene films, coded as “YELLOW”, “NEUTRAL” and “BASF”, were tested during2011 in Southern Italy. The films, provided by Serroplast (Rutigliano, Bari, Italy), werecharacterized by a thickness of 200 μm for the YELLOW, 130 μm for the NEUTRAL and170 μm for the BASF film. The YELLOW and NEUTRAL films were commercial types. TheBASF film, realized for experimental purposes using a masterbatch provided by BASF ItaliaSrl, was a 3-layer structure with all layers having the same thickness; the BASF masterbatchwas added on one of the two outer layers. The plastic film was mounted in the field with thislayer in sky outwards, facing directly the solar radiation.2.1 Radiometric laboratory testsThe radiometric tests, performed on five rectangular samples (50 mm x 70 mm) for each film,were carried out at the University of Bari. Spectral direct transmissivity was measured in thesolar range by means of a double beam UV-VIS-NIR spectrophotometer (Lambda 950,Perkin Elmer Instruments, Norwalk, CT, USA); measurements were carried out in thewavelength band from 200 to 2500 nm, in steps of 10 nm, using radiation with a directperpendicular incidence. Spectral total transmissivity was measured by means of anintegrating sphere (diameter 60 mm) used as receiver of the spectrophotometer, with adouble beam comparative method (Wendlandt & Hecht, 1966). Radiometric properties of thecovering materials were defined by means of the transmissivity coefficients calculated asaverage values of the spectral transmissivity over different wavelength bands: the solarwavelength range (300-2500 nm), the PAR range (400-700 nm) and the long wave infraredradiation (LWIR) range (>3000 nm). The transmissivity coefficient in the solar range wascalculated as the weighted average value of the spectral transmissivity using the spectraldistribution of the solar radiation at the ground level as weighting function (Duffie & Beckman,1991; Papadakis et al., 2000; Vox & Schettini, 2007).The spectral transmissivity in the long wave infrared radiation (LWIR) range, between 2500and 25000 nm, were measured by a FT-IR spectrophotometer (1760 X, Perkin ElmerInstruments, Norwalk, CT, USA) in steps of 4 cm-1. Spectral transmissivity was measuredusing radiation with a direct perpendicular incidence. The transmissivity coefficients in theLWIR range were calculated as average values of the spectral transmissivity in thewavelength range from 7500 to 12500 nm (Vox & Schettini, 2007).2.2 Field testThe experimental field test was carried out at a commercial vineyard located in a viticulturalarea in Southern Italy (Castellaneta Marina, Taranto, Italy, latitude 40° 37’ N, longitude 16°56’ E), where the climate is Mediterranean sub-arid (average maximum air temperatureequal to 33°C in August, average minimum air temperature equal to 3°C in January, and 500mm average rainfalls per year, mostly concentrated from September to April). The soil issandy-clay with low fertility.Vitis vinifera cv. Sublima was grafted onto 140 Ruggeri rootstock and trained to “tendoneoverhead trellis”; the vineyard has plant density of 1600 vines ha -1 (2.50 m x 2.50 m).Sublima is an early-ripening, white-berry seedless table grape cultivar, ripening in late July inopen field, characterized by good productivity, firm pulp, low juice acidity; it requires amoderate gibberellic acid supply to obtain a commercially acceptable berry size.In 2011, 8-year old vines were cane-pruned with four canes per vine (52 buds per vine). Thevineyard was drip-irrigated and received about 1700 m 3 ha -1 , that is, about 50% of the full ETestimated basing on the Penman-Montheith formula (Allen et al., 1998). The other growingtechniques followed the local viticultural practices for table grapes. At the beginning of April,three blocks of Sublima vines were covered with the three plastic films (Fig. 1). Both the topand the lateral vineyard portions were covered until early June when, after the stage of berry

pea-size, the lateral plastic sheets were removed to improve air circulation and reduce airoverheating. Each type of film represented a treatment and was replicated three times; eachreplicate involved a group of ten vine rows.FIGURE 1: The experimental field after covering.Measurements were taken during berry ripening and at commercial harvest from mid June tothe beginning of the second week of July.Per each treatment, the following microclimatic variables were continuously measured (at900 s frequency) and recorded: PAR, air temperature and relative humidity. Sensors anddata loggers were provided by Decagon Devices Inc (Pullman, Washington, USA). The PARsensors were situated over the canopy (2.06 m height); the sensors of air temperature andhumidity were situated both over the canopy (2.00 m) and under the canopy (1.70 m).In a typical day of early July, parameters of physiological leaf functioning were measured,between 09:00 and 12:00 solar time, on well-exposed main leaves of the second node abovethe distal bunch (4 leaves per replicate): leaf temperature (Lafayette TRI-88 infraredthermometer), estimated chlorophyll/nitrogen content (SPAD 502, Minolta Corp., Japan), gasexchange at ~1000 μmol m-2 s-1 of PAR (IRGA, LC pro plus, ADC, Hoddeston, UK).Average values and standard errors were calculated.Grapes were commercially harvested on the 9th of July, when they reached ~ 14°Brix. On 10bunches per replicate, the following parameters were assessed: bunch and berry weight,berries per cluster, berry diameters. On the berry juice, total soluble solids (T.S.S.) by digitalrefractometer (Atago Co. LTD, Japan), pH and titratable acidity expressed as tartaric acid(T.A., neutralization with NaOH 0,1 N) were assessed and T.S.S./T.A. ratio was calculated.These data were statistically processed by means of ANOVA, Duncan test (at p 0.05).3. Results and discussion3.1. Plastic film radiometric propertiesThe transmissivity coefficients of the films were calculated in the solar (300-2500 nm), PAR(400-700 nm) and LWIR (7500-12500 nm) wavelength ranges. The YELLOW film wascharacterized by the highest solar total transmissivity coefficient (86.3%), the BASF film bythe lowest one (82.3%), while this coefficient for the NEUTRAL film was equal to 83.7%. TheYELLOW and BASF films were characterized by PAR total transmissivity coefficients equalto 86.0% and 86.3%, respectively; these values were higher than that obtained for theNEUTRAL film (81.8%). The YELLOW film was characterized by the lowest LWIRtransmissivity coefficient (33.9%), while the BASF film by the highest one (61.2%); thiscoefficient for the NEUTRAL film was equal to 53.6%.

3.2. Microclimate under coversThe microclimatic variables were recorded only during grape ripening (from 21st June to 7thJuly) when the lateral plastic sheets had been removed. Differently from what expectedbased on the film transmissivity coefficients, the air temperature and relative humiditymeasured under the covers, and expressed as average value, were very similar amongtreatments: 24.7°C and 55.7% under the BASF film, 25.0°C and 57.3% under the YELLOWfilm, 24.9°C and 56.8% under the NEUTRAL film. The lack of differences in microclimate waslikely due to the removal of the lateral plastic sheets. The average value of maximum dailyphotosynthetic photon flux was very close for the BASF and the YELLOW films, equal to1505 µmol m -2 s -1 and 1455 µmol m-²s -1 respectively, while it was 1302 µmol m-²s -1 under theNEUTRAL film that, according to the radiometric test, was the least transparent to PAR.3.3. Ecophysiological leaf functioningThe average leaf temperature during the period and the hours of measurement was verywarm, ranging between 38°C and 41°C (Table 1); however, it was 3°C colder for leavesunder the YELLOW and the BASF film than for those under the NEUTRAL one. The leafchlorophyll/nitrogen content showed a tendency to be higher by 12-16% in the BASFtreatment than in the others. The same tendency was found for the leaf gas exchange, thatis, stomatal conductance (CD), net photosynthesis (Pn) and transpiration (TR); the ratesmeasured per leaf area unit were notably higher in the BASF than in the YELLOW treatment,and the NEUTRAL one was almost in the middle. Many studies demonstrated that leaf gasexchange are lowered by too high leaf temperature and that leaf photosynthesis is positivelycorrelated with leaf chlorophyll/nitrogen content (Kriedemann, 1968; Williams & Smith, 1985;Mebratu et al., 1991) Hence, it is possible that the combination of the best performance ofthese two variables played a role in the best physiological performance observed for theleaves of vines grown under the BASF film. Nevertheless, it is not clear which factors mightimprove the chlorophyll/nitrogen status in this treatment, thus other field variables, such asthe total shoot growth, should be examined. However, the leaf gas exchange rates were notvery stable within each thesis, as it was pointed out by the standard error; in our experience,this result is common for leaves under plastic cover that experience very high temperatureslike those measured in this trial.Table 1. Parameters of ecophysiological leaf functioning measured close to berry ripening,on the second main leaf over the distal cluster, in vines covered with the three plastic films(average values standard error).Plastic FilmLeaftemperature(°C)SPADunitsEcophysiological parametersCD(mol m -2 s -1 )PN(umol m -2 s -1 )TR(mmol m -2 s -1 )YELLOW 38 0.3 32.3 1,5 0.5 0.2 4.1 0.6 3.8 1.0NEUTRAL 41 1,2 31.2 1,4 0.8 0.4 4.8 1.3 4.4 1.2BASF 38 1.0 36.2 1,7 1.0 0.3 7.1 0.9 5.1 1.13.4. Vine productivity and berry qualityCompared to the BASF film, the YELLOW and the NEUTRAL films lowered the vineproductivity (Fig. 2). The bunch weight, that reached about 760 g in the BASF treatment,decreased by 30% and 60% under the YELLOW and the NEUTRAL covers, respectively; theberry weight, that reached about 3.9 g under the BASF cover, decreased by 14% and 31%under the YELLOW and the NEUTRAL films, respectively. As a consequence, the grapeyield obtained using the YELLOW and the NEUTRAL films was about 40-45% lower thanthat obtained under the BASF film (10.5 kg per vine), coherently with the difference observedin terms of the photosynthetic rate close to berry ripening.

In this trial, the total soluble solid concentration was not influenced by the plastic film, whilethe juice acidity was affected by the cover (Fig. 3). The YELLOW film reduced the juice pHand the NEUTRAL film reduced the titratable acidity, that is notoriously sensitive to the warmtemperatures since they accelerate the malic acid respiration (Lakso & Kliewer, 1975). As aconsequence of the T.S.S./T.A. balance, grapes produced under the NEUTRAL coverreached a higher “ripening level” at the time of commercial harvest. This improvement maybe quantified as +30% respect to the YELLOW and +23% respect to the BASF film.Nonetheless, 1 g L -1 more titratable acidity found in the berry juice of the last treatment mayconfer a fresher taste that is one of the characteristic required to early ripening white grapes.1000g750500YELLOW film NEUTRAL film4 a 15aba gkgb310bb2BASF filmab b250150bunch weight0berry weight0yield per vineFIGURE 2: Components of grape production, in vines covered with the three plastic films;different letters indicate statistical differences at p 0.05.YELLOW film15 n.s.°Brix107.5g L -15.0NEUTRAL filma ab43BASF filmb a a4030bab22052.51100Total SolubleSolids0.0TitratatableAcidity0pH0T.S.S./T.A.FIGURE 3: Parameters of berry juice quality, in vines covered with the three plastic films;different letters indicate statistical differences at p 0.05; n.s. = not significantdifferences.4. ConclusionsThe experimental test carried out confirmed that the characteristics of the plastic films usedto protect the vineyard influence the vine production either in terms of quantitative orqualitative traits.Sublima deficit-irrigated vines obtained the highest photosynthetic rates, the biggest berryweight and the greatest grape yield when covered with the BASF film that wasexperimentally realized in order to reduce the overheating under covering. The latter factor isknown to have a detrimental effect on the ecophysiological leaf functioning, the berry growthand the berry ripening. It is likely that the lowering of the under covering overheating may be

particularly important in the warm regions and under growing conditions that include otherlimiting factors, e.g. a severe cut off of the irrigation water supply, such as in this trial.The choice of the plastic film becomes strategic not only to protect the vineyard againstenvironmental hazards but also to sustain the grape production under abiotic stress.AcknowledgementsThe work was supported by the Italian Ministry of Agriculture and Forestry Policy (BandoOIGA D.M 2065 del 13/02/2008), Project “Razionalizzazione dell'apporto irriguo e studioecofisiologico nella produzione di uve apirene in semiforzatura precoce e tardiva”; publicationn° 2.The authors shared programming and editorial work equivalently within the areas of theirexpertiseReferencesAllen, R. G., Pereira, L. S., Raes, D. & Smith, M. (1998) Crop evapotranspiration. Guidelinesfor computing crop water requirements. Irrigation and Drainage Paper N.56, FAO, Rome.de Palma, L., Novello, V. & Tarricone, L. (1999) Changes of solar radiation and air CO2concentration: effects on ecophysiological activity, vine growth and production in table grapegrown under protected conditions. Proc. XI GESCO, 2, 711-717.Du, T. S., Kang, S. Z., Zhang, J. H., Li, F. S. & Yan, B. Y. (2008) Water use efficiency andfruit quality of table grape under alternate partial root-zone drip irrigation. Agricultural WaterManagement, 95(6), 659-668.Duffie, J. A. & Beckman, W. A. (1991) Solar Engineering of Thermal Processes. John Wiley& Sons. New YorkEzzahouani, A. & Williams, L. E. (2007) Effect of irrigation amount and preharvest irrigationcutoff date on vine water status and productivity of Danlas grapevines. American Journal ofEnology and Viticulture, 58 (3), 330-340.Kriedemann, P. E. (1968) Photosynthesis in vine leaves as a function of light intensity,temperature and leaf age. Vitis, 7, 213-220.Lakso, A. N. & Kliewer, W. M. (1975) The influence of temperature on malic acid metabolismin grape berries. I Enzyme responses. Plant Physiology, 56, 370-37278.Mebrahtu T., Hanover J. W., Layne D. R. & Flore J. A. (1991). Leaf temperature effects onnet potosynthesis, dark respiration, and photorespiration of seedlings of black locust familieswith contrasting growth rates. Can. J. For. Res. 21,1616-1621.Novello, V., de Palma, L., Tarricone, L. & Vox, G. (2000) Effect of different plastic sheetcoverings on microclimate and berry ripening in table grape cv Matilde. Journal Internationaldes Sciences de la Vigne et du Vin, 34(2), 49-55.Papadakis, G., Briassoulis, D., Scarascia Mugnozza, G., Vox, G., Feuilloley, P. & Stoffers, J.A. (2000) Radiometric and Thermal Properties of, and Testing Methods for, GreenhouseCovering Materials. Journal of Agricultural Engineering Research, 77(1), 7-38.Tarricone, L. (2003) Caratteristiche produttive del vitigno Sugraone in coltura protetta perl’anticipo della maturazione. Rivista di Frutticoltura, 65(4), 36-40.Vox, G. & Schettini, E. (2007) Evaluation of the radiometric properties of starch-basedbiodegradable films for crop protection. Polymer Testing, 26(5), 639-651.Wendlandt, W. W. & Hecht, H. G. (1966) Reflectance spectroscopy. John Wiley and Sons,New York, pp. 253-274.Williams, L. E. (2000) Grapevine water relations. In L.P. Christiansen (ed) Raisin ProductionManual. DANR Publications, Univ. California, Oakland, CA., pp. 121-126.Williams, L. E, Grimes, D. W. & Phene, C. J. (2010) The effects of applied water at variousfractions of measured evapotranspiration on reproductive growth and water productivity ofThompson Seedless grapevines. Irrigation Science, 28(3), 233-243.Williams, L. E. & Smith, R. J. (1985) Net CO2 assimilation rate and nitrogen content of grapeleaves subsequent to fruit harvest. Journal of the American Society for Horticultural Science,110(6), 846-850.