Thesis (MScAgric)--Stellenbosch University, 2014 / ENGLISH ABSTRACT: The objective of the study was to determine combined effects of irrigation and canopy
management practices on grapevine water status, growth, yield and juice
characteristics. The field study was carried out with Shiraz/110R grapevines in the
Breede River Valley. Grapevines were drip irrigated at 30%, 60% and 90% plant
available water (PAW) depletion, respectively. For each PAW level, grapevines had (i)
suckered, vertical shoot positioned (VSP), (ii) non-suckered, VSP and (iii) sprawling
canopies. Treatments were replicated three times in a randomised block design and
applied during the 2011/12 and 2012/13 seasons.
Irrigation applied at low PAW depletion levels, i.e. high frequency irrigation, required
substantially higher irrigation volumes compared to high depletion levels, i.e. low
frequency irrigation. Low frequency irrigation increased grapevine water constraints
compared to high frequency irrigation. Sprawling canopy grapevines experienced more
water constraints than VSP grapevines. Grapevines irrigated at 90% PAW depletion
experienced strong water constraints. Low frequency irrigation seemed to accelerate
berry ripening compared to high frequencies, probably due to smaller berries and lower
yields. Sprawling canopies consistently enhanced berry ripening due to more sunlight
interception by the leaves. Berry ripening of VSP grapevines was slower, but
inconsistent between seasons.
Level of PAW depletion and canopy management practice did not affect number of
leaves per primary shoot. Low frequency irrigation reduced number of leaves per
secondary shoot. Leaf number per shoot contributed more to total leaf area than leaf
size. Level of PAW depletion did not affect number of shoots per grapevine. Suckering
reduced number of shoots per grapevine. Low frequency irrigation reduced total leaf
area per grapevine compared to high frequency irrigation. Effects of canopy
management practice were more pronounced in the case of high frequency irrigation
compared to low frequency irrigation. At pruning, primary cane length was not affected
by level of PAW depletion or canopy management practice. Secondary cane mass and
diameter were not affected by canopy management practice. Multiple linear regression
showed that cane mass was a function of cane length and diameter.
Low frequency irrigation reduced berry mass compared to high frequency irrigation,
irrespective of canopy management practice. However, at harvest there was no
difference in berry mass between 30% and 60% PAW depletion. Low irrigation The objective of the study was to determine combined effects of irrigation and canopy
management practices on grapevine water status, growth, yield and juice
characteristics. The field study was carried out with Shiraz/110R grapevines in the
Breede River Valley. Grapevines were drip irrigated at 30%, 60% and 90% plant
available water (PAW) depletion, respectively. For each PAW level, grapevines had (i)
suckered, vertical shoot positioned (VSP), (ii) non-suckered, VSP and (iii) sprawling
canopies. Treatments were replicated three times in a randomised block design and
applied during the 2011/12 and 2012/13 seasons.
Irrigation applied at low PAW depletion levels, i.e. high frequency irrigation, required
substantially higher irrigation volumes compared to high depletion levels, i.e. low
frequency irrigation. Low frequency irrigation increased grapevine water constraints
compared to high frequency irrigation. Sprawling canopy grapevines experienced more
water constraints than VSP grapevines. Grapevines irrigated at 90% PAW depletion
experienced strong water constraints. Low frequency irrigation seemed to accelerate
berry ripening compared to high frequencies, probably due to smaller berries and lower
yields. Sprawling canopies consistently enhanced berry ripening due to more sunlight
interception by the leaves. Berry ripening of VSP grapevines was slower, but
inconsistent between seasons.
Level of PAW depletion and canopy management practice did not affect number of
leaves per primary shoot. Low frequency irrigation reduced number of leaves per
secondary shoot. Leaf number per shoot contributed more to total leaf area than leaf
size. Level of PAW depletion did not affect number of shoots per grapevine. Suckering
reduced number of shoots per grapevine. Low frequency irrigation reduced total leaf
area per grapevine compared to high frequency irrigation. Effects of canopy
management practice were more pronounced in the case of high frequency irrigation
compared to low frequency irrigation. At pruning, primary cane length was not affected
by level of PAW depletion or canopy management practice. Secondary cane mass and
diameter were not affected by canopy management practice. Multiple linear regression
showed that cane mass was a function of cane length and diameter.
Low frequency irrigation reduced berry mass compared to high frequency irrigation,
irrespective of canopy management practice. However, at harvest there was no
difference in berry mass between 30% and 60% PAW depletion. Low irrigation. / AFRIKAANSE OPSOMMING: Die doelwit van hierdie studie was om die gekombineerde effek van besproeiing en
lowerbestuurspraktyke op wingerd waterstatus, groei, opbrengs en druiwesap
eienskappe te bepaal. Die veld studie is uitgevoer met Shiraz/110R wingerdstokke in
die Breede Rivier Vallei. Wingerdstokke was d.m.v. drupbesproeiing teen 30%, 60% en
90% plant beskikbare water (PBW) ontrekking, onderskeidelik besproei. Vir elke PBW
ontrekkingspeil, was wingerdstokke (i) gesuier en vertikale lootposisionering toegepas,
(ii) ongesuier en vertikale lootposisionering toegepas en (iii) geen lowerbestuur
toegepas nie (lowers wat oophang). Behandelings is drie keer in ‘n ewekansige
blokontwerp herhaal en tydens die 2011/12 en 2012/13 seisoene toegepas.
Besproeiing wat teen ‘n lae PBW ontrekkingspeil toegedien is, d.w.s. hoë frekwensie
besproeiing, vereis aansienlik hoër besproeiings volumes i.v.m. hoë besproeiing
ontrekkingspeile, d.w.s. lae frekwensie besproeiing. Wingerdstokke wat oopgehang het
meer watertekorte as vertikaal lootgeposisioneerde wingerdstokke ervaar.
Wingerdstokke wat teen 90% PBW ontrekking besproei was, het sterk watertekorte
ervaar. Dit het voorgekom of lae frekwensie besproeiing korrelrypwording versnel het
i.v.m. hoë frekwensie besproeiing. Dit was heelwaarskynlik a.g.v. kleiner korrels en laer
opbrengste. Wingerdstokke wat oophang het, het konsekwent korrelrypwording versnel
a.g.v. meer sonligonderskepping deur die blare. Korrelrypwording van vertikaal
lootgeposisioneerde wingerdstokke was stadiger, maar teenstrydig tussen die seisoene.
Plant beskikbare water ontrekkingspeil en lowerbestuurspraktyke het geen invoeld
gehad op die aantal blare per primêre loot nie. Lae frekwensie besproeiing het die
aantal blare per sekondêre loot verminder. Die hoeveelheid blare per loot het ‘n groter
bygedra gemaak i.v.m. blaar grootte. Plant beskikbare water ontrekkingspeil het geen
invloed gehad op die aantal lote per wingerdstok nie. Suier verminder die aantal lote per
wingerdstok. Lae frekwensie besproeiing verminder die totale blaar oppervlak i.v.m. hoë
frekwensie besproeiing. Die effek van lowerebestuurspraktyke is duideliker sigbaar by
hoë frekwensie besproeiing i.v.m. lae frekwensie besproeiing. Primêre lootlengte was
nie deur PBW ontrekkingspeil of lowerbestuurspraktyke beïnvloed nie. Sekondêre
lootmassa en -deursnit is nie deur lowerbestuurspraktyk beïnvloed nie. Meervoudige
lineêre regressie het getoon dat lootmassa ‘n funksie van lootlengte en -deursnit was.
Lae frekwensie besproeiing het korrelmassa verminder ongeag die
lowerbestuurspraktyk i.v.m. hoë frekwensie besproeiing. Daar was egter geen verskil in
korrelmassa by oes tussen 30% en 60% PBW ontrekking nie. Lae frekwensie
besproeiing was geneig om suiker akkumulasie te versnel i.v.m. hoë frekwensie
besproeiing. Wingerdstokke wat oopgehang het, het veral by lae frekwensie besproeiing
korrelrypwording versnel i.v.m. vertikaal lootgeposisioneeide wingerdstokke.
Suikerinhoud per korrel het geneig om toe te neem totdat dit ‘n plato bereik het. Hierdie
plato was meer prominent by hoë frekwensie besproeiing i.v.m. lae frekwensie
besproeiing. Wingerdstokke wat oopgehang het, het ook hierdie plato vroeër bereik
i.v.m. vertikaal lootgeposisioneerde wingerdstokke. By oes was die totale titreerbare
suur (TTS) hoër vir wingerdstokke wat vroeër geoes was. As gevolg van versnelde
rypwording was TTS van wingerdstokke wat teen lae frekwensie besproei is hoër i.v.m.
hoë frekwensie besproeiing. ‘n Ligter oeslading in verhouding tot ‘n hoër blaaroppervlak
het ook gelei tot hoër TTS by oes. Plant beskikbare water ontrekkingspeil en
lowerbestuurspraktyke het geen invloed op die pH gehad met oes nie.
Die hoeveelheid trosse per wingerdstok het nie duidelike tendense gewys wat verbind
kon word met watertekorte wat deur die stokke ervaar is nie. Gesuierde vertikaal
lootgeposisioneerde wingerdstokke het die hoeveelheid trosse per stok verminder i.v.m.
die ongesuierde vertikaal lootgeposisioneerde wingerdstokke en wingerstokke wat
oopgehang het. Trosmassa het dieselfde tendense as korrels per tros gevolg. Lae
frekwensie besproeiing het opbrengs aansienlik verminder i.v.m. hoë frekwensie
besproeiing. Gesuierde vertikaal lootgeposisioneerde wingerdstokke het geneig om
opbrengste te verminder i.v.m. ongesuierde vertikaal lootgeposisioneerde
wingerdstokke. Hierdie effek het egter verdwyn waar wingerdstokke teen 90% PBW
ontrekking besproei was. Druif skade a.g.v. suurvrot was meer prominent by hoë
frekwensie besproeiing, veral vir ongesuierde vertikaal lootgeposisioneerde
wingerdstokke. Total opbrengs verlies, uitgedruk as ‘n persentasie, was hoofsaaklik ‘n
funksie van sonbrand eerder as ‘n funksie van suurvrot.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/86470 |
| Date | 04 1900 |
| Creators | Stolk, Robert |
| Contributors | Myburgh, P. A., Strever, A. E., Lategan, E. L., Stellenbosch University. Faculty of AgriSciences. Department of Viticulture and Oenology. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | Unknown |
| Type | Thesis |
| Format | xix, 122 p. : ill. |
| Rights | Stellenbosch University |
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