Thesis (MScAgric)--University of Stellenbosch, 2007. / ENGLISH ABSTRACT: The macro-element uptake and distribution by higher density central leader
‘Donnarine’ nectarine trees was studied through the sequential excavation of trees. A
large portion, 41.5%, of the nitrogen manifested in the new growth from dormancy up
to pit-hardening, originated from nitrogen reserves in the permanent structure. The
permanent structure was also an important source of phosphorous reserves. Of the
phosphorous in the fruit, leaves and new shoots at pit-hardening, 35.0% came from
reserves in the permanent structure. Potassium did not act as an important reserve in
the nectarine trees and was taken up throughout the season. From pit hardening to
harvest the fruit represented the most important sink for potassium. Calcium and
magnesium, like potassium, did not play significant roles as reserves in the nectarine
tree and must be available for uptake from the beginning of the season for new growth
and development as well as fruit quality.
The micro-element uptake and distribution was also studied through the sequential
excavation of the same ‘Donnarine’ nectarine trees. Little scientific data is available
on this topic. Manganese and iron was found to act as important reserves in the tree
with 46.2% of manganese and 59.5% of the iron found in the new growth at pithardening
coming from reserves translocated from the permanent structure. Zinc and
boron reserves also play a role in nectarine trees, but to a lesser extent than
manganese and iron.
The seasonal mineral nutrient demand of the same ‘Donnarine’ nectarine trees was
determined through the sequential excavation of trees and losses and fixation was
calculated. Guidelines regarding nutritional requirements per ton of fruit produced per
hectare by higher density nectarine orchards are respectively 3.82kg nitrogen, 0.35kg
phosphorous, 4.43kg potassium, 1.53kg calcium, 0.52kg magnesium, 32.45g sodium,
9.44g manganese, 37.46g iron, 3.24g copper, 13.95g zinc and 10.52g boron. Sodium
is not commonly considered to be essential to higher plants, but was included in the
trial.
Nutrient solutions with four different EC (electrical conductivity) levels were applied
to ‘Donnarine’ nectarine trees under pulsating drip fertigation for three periods of different lengths, before harvest. Raising the nutrient solution EC to positively affect
fruit quality is a technique widely utilised in the vegetable industry. This technique
did, however, not have similar positive effects on nectarine fruit grown under a
pulsating drip fertigation system. Good production practices such as accurate nutrition
and irrigation as well as the correct horticultural inputs should be the primary focus of
producers who wish to alter or improve the fruit quality of their crop. / AFRIKAANSE OPSOMMING: Voedingbestuur strategieë in nektarien boorde
Die makro-element opname en verspreiding deur hoër digtheid sentrale leier
‘Donnarine’ nektarien bome is bestudeer d.m.v. opeenvolgende opgrawings van
volledige bome en die ontleding van monsters. ‘n Groot hoeveelheid, 41.5%, van die
stikstof wat tydens pitverharding in die nuwe groei teenwoordig was, is d.m.v.
translokasie vanuit die permanente struktuur van die boom afkomstig. Die permanente
struktuur was ook ‘n belangrike bron van fosfaat reserwes. Teen pitverharding was
35.0% van die fosfaat in die nuwe groei afkomstig vanuit die permanente struktuur.
Bevindings het getoon dat kalium nie as ‘n reserwe in die nektarien bome opgetree het
nie en dié element is deur die groeiseisoen opgeneem. Vanaf pitverharding tot en met
oestyd was die vrugte die sterkste setel van aanvraag vir kalium. Kalsium en
magnesium het, soos in die geval van kalium, nie ‘n belangrike rol as reserwe vertolk
nie. Beskikbaarheid van hierdie elemente vir opname vanaf die begin van die
groeiseisoen is dus baie belangrik vir nuwe groei en ontwikkeling asook
vrugkwaliteit.
Die mikro-element opname en distribusie van dieselfde ‘Donnarine’ nektarien bome
is ook bestudeer d.m.v. opeenvolgende opgrawings en analise van volledige bome.
Min wetenskaplike literatuur oor hierdie onderwerp is beskikbaar. Bevindings het
getoon dat mangaan asook yster baie belangrike reserwes in die nektarien boom is.
Tydens pitverharding was 46.2% van die mangaan en 59.5% van die yster wat in die
nuwe groei teenwoordig was, afkomstig vanaf reserwes uit die permanente struktuur
van die boom. Verder het sink en boor ook as reserwes opgetree, maar tot ‘n mindere
mate as mangaan en yster. Die seisoenale behoeftes aan minerale voeding van dieselfde ‘Donnarine’ nektarien
bome is bepaal d.m.v. opeenvolgende opgrawings en analise van volledige bome
asook die bepaling van verwyderingsverliese en vaslegging. Voedingsriglyne is
vasgestel i.t.v. die hoeveelheid voedingstof wat per hektaar benodig word om een ton
nektariens te produseer. Die riglyne is as volg: 3.82kg stikstof, 0.35kg fosfaat, 4.43kg
kalium, 1.53kg kalsium, 0.52kg magnesium, 32.45g natrium, 9.44g mangaan, 37.46g
yster, 3.24g koper, 13.95g sink en 10.52g boor. Natrium word nie in die algemeen as
‘n essensiële plantvoedingselement beskou nie, maar is by die berekeninge ingesluit. Voedingsoplossing met vier verskillende vlakke van EG (elektriese geleiding) is vir
drie periodes van verskillende lengtes aan ‘Donnarine’ nekarien bome toegedien. Die
verhoging van die EG van voedingsoplossings ten einde kwaliteit te verbeter is ‘n
tegniek wat met groot suskses in die groentbedryf toegepas word. Hierdie tegniek het
egter nie soortgelyke positiewe effekte op die nektarien vrugkwaliteit gehad nie.
Produsente wat hul vrugkwaliteit wil verbeter behoort primêr te fokus op goeie
produksiepraktyke soos akkurate voeding en besproeiing asook die korrekte
tuinboukundige insette.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/21667 |
| Date | 12 1900 |
| Creators | Krige, Graeme Tertius |
| Contributors | Stassen, P.J.C., Hoffman, J.E., Stellenbosch University. Faculty of Agrisciences. Dept. of Horticulture. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | Unknown |
| Type | Thesis |
| Format | vii, 104 leaves : ill. |
| Rights | Stellenbosch University |
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