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The effect of fertilising pinus radiata stands at mid rotation age in the Western Cape Province on leaf area, growth efficiency and stand productivity

Thesis (MScFor (Forest and Wood Science))--University of Stellenbosch, 2010.

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Main Author: Badenhorst, Johannes Jurie
Other Authors: Du Toit, Ben
Format: Thesis
Language:English
Published: Stellenbosch : University of Stellenbosch 2010
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access_status_str Open Access
author Badenhorst, Johannes Jurie
author2 Du Toit, Ben
author_browse Badenhorst, Johannes Jurie
Du Toit, Ben
author_facet Du Toit, Ben
Badenhorst, Johannes Jurie
author_sort Badenhorst, Johannes Jurie
collection Thesis
dc_rights_str_mv University of Stellenbosch
description Thesis (MScFor (Forest and Wood Science))--University of Stellenbosch, 2010.
format Thesis
id oai:scholar.sun.ac.za:10019.1/4375
institution Stellenbosch University (South Africa)
language English
last_indexed 2026-06-10T12:41:44.687Z
license_str Other — see source repository
provenance_str_mv Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository
publishDate 2010
publishDateRange 2010
publishDateSort 2010
publisher Stellenbosch : University of Stellenbosch
publisherStr Stellenbosch : University of Stellenbosch
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spelling oai:scholar.sun.ac.za:10019.1/4375 The effect of fertilising pinus radiata stands at mid rotation age in the Western Cape Province on leaf area, growth efficiency and stand productivity Badenhorst, Johannes Jurie Du Toit, Ben University of Stellenbosch. Faculty of Agrisciences. Dept. of Forest and Wood Science. Pinus radiata -- Fertilization -- South Africa -- Werstern Cape Mid rotation fertilisation Dissertations -- Forest and wood science Theses -- Forest and wood science Forest and Wood Science Thesis (MScFor (Forest and Wood Science))--University of Stellenbosch, 2010. ENGLISH ABSTRACT: Mid rotation fertiliser application is generally practised in forestry to enhance nutrient availability in areas were soils are impoverished and do not provide sufficient nutrients for high productivity. Generally speaking there is great potential for mid rotation fertiliser in pine plantations, but stand and site characteristics such as water availability, soil depth, stand density and available nutrients need to be considered before fertiliser treatments are implemented. Foliar nutrient analyses were used to estimate nutrient availability. These levels were measured throughout the study and were used to implement specific fertiliser treatments that would boost nutrient availability. Treatments consisted of an unfertilised control, a single fertiliser application (1F) and two fertiliser applications over two consecutive years (2F). Leaf area index (LAI) and stem volume increment were measured in order to evaluate its influence on growth efficiency. LAI was estimated using the gap fraction method with the use of a ceptometer. Volume increment was calculated with diameter and height measurements. Basal area was calculated by means of diameter measurements. These growth responses were used to determine the effect of increased nutrient availability and although increases were found in LAI, volume increment, basal area increment and growth efficiency, none were significant. The lack of significance may be due to relatively large variations in other factors such as stand density and initial volume of the experimental plots. The 18 month monitoring period apparently did not allow complete reaction time to increased nutrient availability and limited our understanding of the responses somewhat. Despite this, the magnitude of some growth responses was large as nutrient ratios in the foliage increased to levels within the norms range. Increases in current annual volume increment (CAI) of 3.48 m3 ha-1 a-1 and 3.62 m3 ha-1 a-1 in 1F plots at Grabouw and La Motte plantations indicated that it may be economically feasible to fertilise at mid rotation age as the NPV and IRR increased over a projected 25 year rotation. The Grabouw site had the most significant response with regards to CAI in 2F treatment with a mean volume increment of 5.43 m3 ha-1 a-1. The mechanism of the response was examined further by taking water availability and soil characteristics into account. The seasonal climatic effect (length of the moisture growing season) had a significant influence on the response to fertilisation. AFRIKAANSE OPSOMMING: Die toediening van mid-rotasie bemesting word algemeen in bosbou toegepas om voedingstofbeskikbaarheid te verhoog in areas waar voedingstowwe onvoldoende is vir hoë produktiwiteit. Daar is oor die algemeen ruim potensiaal vir mid-rotasie bemesting in denne plantasies, maar eienskappe soos waterbeskikbaarheid, gronddiepte, opstanddigtheid en beskikbaarheid van voedingstowwe moet in ag geneem word voor optimum bemestingtoedienings bepaal kan word. Blaaranalise is gebruik om voedingstofbeskikbaarheid in plantasies te skat. Hierdie voedingstofvlakke is deurgans gemeet en is gebruik om spesifieke bemestingsbehandelings te implementeer wat voedingstofbeskikbaarheid kon opstoot. Behandelings het bestaan uit ‘n onbemeste kontrole, ‘n eenmalige kunsmistoediening (1F) en twee kunsmistoedienings in opeenvolgende jare (2F). Blaar oppervlak indeks en toename in stamvolume is gemeet om die invloed daarvan op die effektiwiteit van groei te bepaal. Blaaroppervlakindeks is bepaal deur middel van die gapingfraksie metode met behulp van ‘n stralingsmeter. Toename in volume is bereken met stamdeursnee en hoogte meetings. Basale oppervlakte is bereken deur middel van deursnee metings. Hierdie groeireaksies is gebruik om die effek van verbeterde voedingstofbeskikbaarheid te bepaal. Al die groeireaksies het toegeneem maar was nie statisties beduidend nie. Die gebrek aan beduidende toename kan toegeskryf word aan variasies in opstandsdigtheid en oorspronklike volume van die bome in die navorsingspersele. Die toetstydperk van 18 maande het moontlik nie genoeg tyd gegee vir die bome om op die toename in voedingstofbeskikbaarheid te reageer nie. ‘n Goeie groeirespons is wel waargeneem waar die voedingstofverhoudings in die naalde aanvaarbare norme bereik het. Die toename in volume aanwas van tussen 3.48m3 ha-1 a-1 en 3.62 m3 ha-1 a-1 in 1F persele by Grabouw en La Motte plantasies het aangedui dat dit ekonomies lewensvatbaar is om op mid-rotasie ouderdom bemesting toe te dien aangesien die netto teenswoordige waarde en die interne opbrengs koers toegeneem het op ‘n geprojekteerde 25 jaar rotasie. Die persele op Grabouw plantasie het die mees beduidende respons getoon met betrekking tot huidige jaarlikse aanwas (5.43 m3 ha-1 a-1 in die 2F perseel). Die meganisme van die respons is verder nagevors met inagneming van waterbeskikbaarheid en grondeienskappe. Die seisoenale klimaatseffek (lengte van die vog-groeiseisoen) het ‘n beduidende impak op die respons tot bemesting. Masters 2010-02-11T14:48:06Z 2010-08-13T15:02:07Z 2010-02-11T14:48:06Z 2010-08-13T15:02:07Z 2010-03 Thesis http://hdl.handle.net/10019.1/4375 en University of Stellenbosch 65 p. : ill., maps application/pdf Stellenbosch : University of Stellenbosch
spellingShingle Pinus radiata -- Fertilization -- South Africa -- Werstern Cape
Mid rotation fertilisation
Dissertations -- Forest and wood science
Theses -- Forest and wood science
Forest and Wood Science
Badenhorst, Johannes Jurie
The effect of fertilising pinus radiata stands at mid rotation age in the Western Cape Province on leaf area, growth efficiency and stand productivity
title The effect of fertilising pinus radiata stands at mid rotation age in the Western Cape Province on leaf area, growth efficiency and stand productivity
title_full The effect of fertilising pinus radiata stands at mid rotation age in the Western Cape Province on leaf area, growth efficiency and stand productivity
title_fullStr The effect of fertilising pinus radiata stands at mid rotation age in the Western Cape Province on leaf area, growth efficiency and stand productivity
title_full_unstemmed The effect of fertilising pinus radiata stands at mid rotation age in the Western Cape Province on leaf area, growth efficiency and stand productivity
title_short The effect of fertilising pinus radiata stands at mid rotation age in the Western Cape Province on leaf area, growth efficiency and stand productivity
title_sort effect of fertilising pinus radiata stands at mid rotation age in the western cape province on leaf area growth efficiency and stand productivity
topic Pinus radiata -- Fertilization -- South Africa -- Werstern Cape
Mid rotation fertilisation
Dissertations -- Forest and wood science
Theses -- Forest and wood science
Forest and Wood Science
url http://hdl.handle.net/10019.1/4375
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