Nutrient requirement and distribution of intensively grown ‘Brookfield Gala’ apple trees By Grace Nandesora Kangueehi Thesis presented in partial fulfilment of the requirements for the degree Master of Science in Agriculture in the Department of Horticultural Science, University of Stellenbosch, South Africa Supervisor: Prof P.J.C Stassen (Department of Horticulture Science, Stellenbosch University) Co-supervisor: Prof K.I Theron (Department of Horticulture Science, Stellenbosch University) Co-supervisor: Prof R. Rosecrance (College of Agriculture, California State University, Chico) March 2008 i DECLARATION I, the undersigned , hereby declare that the work contained in this thesis is my own original work and has not previously, in its entirety or in part, been submitted at any university for a degree. ………………………. ……………………. Signature Date Copyright ©2008 Stellenbosch University All rights reserved ii SUMMARY ‘Brookfield Gala’ apple trees were planted out in July 2003 in a Dundee soil form, consisting of well-aerated sandy loam soil. During the first 12 months trees received young tree solutions high in nitrogen. The nutrient solution of the 2nd leaf trees was based on a yield estimation of 10 ton. ha-1 plus 30%. Nutrient solutions for the 3rd leaf trees were based on 25 ton. ha-1 yield estimations and adapted upwards. Seasonal uptake and distributions were determined for macro and micro elements, using two- and three-year-old apple trees during the seasons 2004/2005 and 2005/2006. In the bearing apple trees the macro nutrient accumulated rapidly from late winter to late autumn. Prior to leaf drop most of the N, P, S, Mg and a small portion of K were redistributed back into the permanent parts of the tree. On the other hand, all Ca in the leaves was lost through leaf drop. Apple fruit contains comparatively large quantities (±60.2%) of K, which are removed during harvest. Guidelines for minimum and maximum nutritional requirements based on the amount necessary to produce 1 kg fruit were determined. For the 3rd leaf trees the minimum macro nutrient requirements (g. kg-1 yield) of N, P, K, Ca, Mg and S were ±1.7, ±0.3, ±2.3, ±0.5, ±0.2 and ±0.2, respectively. The maximum nutrient requirements (g. kg-1 yield) for N, P, K, Ca, Mg and S were ±2.6, ±0.4, ±3.3, ±1.9, ±0.4 and ±0.2, respectively. For the 3rd leaf trees the minimum micro nutrient requirements (mg. kg-1 yield) of Na, Mn, Fe, Cu, Zn, B and Mo were ±75.1, ±1.3, ±28.7, ±0.9, ±3.0, ±5.7 and ±0.3, respectively. The maximum nutrient requirements (mg. kg-1 yield) of Na, Mn, Fe, Cu, Zn, B and Mo were ±102.9, ±7.8, ±32.6, ±1.1, ±6.5, ±7.6 and ±0.3, respectively. Labelled N uptake and distribution for two- and three-year-old apple trees were also determined during the same seasons. The labelled N uptake and distribution results indicated that there was a low labelled N uptake in the initial growth stages, suggesting the importance of internal N reserves for plant development at the beginning of the season. In the active growing period more than 60% of the labelled N was found in the new growth. Uptake efficiency improved as the trees grew older. iii The effect of different nutrient levels on tree growth, yield and fruit quality was assessed: lower (80%) than the standard (100%) and three higher (120%, 140% and 160%). Results indicated that different nutrient levels had no effect on yield, blush or TSS during the 18 months of application over two bearing seasons. The application of biological products (humic acid, and compost plus compost extract) over a period of 18 months had a significant influence on the TSS, malic acid and citric acid concentrations. A tendency towards an increase in total fine root number and length occured with the addition of biological ameliorant. iv OPSOMMING ‘Brookfield Gala’ appelbome is in Julie 2003 in ‘n Dundee grond bestaande uit sanderige leemgrond wat goed deurlug is, uitgeplant. Gedurende die eerste 12 maande het die bome ʼn jongboom oplossing wat hoog is in stikstof ontvang. Die oplossing vir die 2de blad boompies is gebaseer op ‘n opbrengs skatting van 10 ton.ha-1 plus 30% meer. Die voedingoplossing vir die drie-jaar-oue boompies is gebaseer op ‘n 25 ton.ha-1 opbrengs skatting. Twee- en drie-jarige appelbome is gedurende die 2004/2005 en 2005/2006 seisoene gebruik om die seisoenale opname en verspreiding van makro- en mikro-elemente vas te stel. In vrugdraende appelbome het die makro- voedingselemente akkumulasie vinnig vanaf laatwinter tot laat herfs toegeneem. Tydens blaarval word die meeste van die N, P, S, Mg en ‘n klein gedeelte K herversprei na die permanente dele van die boom. Al die Ca in die blare gaan egter verlore tydens blaarval. Die appelvrug bevat relatief groot hoeveelhede (omtrent 60.2%) K wat tydens die oes verwyder word. Riglyne vir die minimum en maksimum voedingsvereistes gebaseer op die hoeveelheid benodig om 1 kg vrugte te produseer, is vasgestel. Vir die derde-blad bome was die minimum makro voedingselemente vereiste (g.kg-1 opbrengs) van N, P, K, Ca, Mg en S, onderskeidelik ±1.7, ±0.3, ±2.3, ±0.5, ±0.2 en ±0.2. Die maksimum voedingselemente vereistes (g.kg-1 opbrengs) vir N, P, K, Ca, Mg, en S was onderskeidelik ±2.6, ±0.4, ±3.3, ±1.9, ±0.4, en ±0.2. Vir die derde-blad bome was die minimum mikro voedingselemente vereiste (mg.kg –1 opbrengs ) van Na, Mn, Fe, Cu, Zn, B, en Mo, onderskeidelik ±75.1, ± 1.3, ± 28.7, ± 0.9, ±3.0, ± 5.7 en ± 0.3. Die maksimum voedingselemente vereiste (mg.kg –1 opbrengs) van Na, Mn, Fe, Cu, Zn, B, Mo was onderskeidelik ±102.9, ±7.8, ±32.6, ±1.1, ±6.5, ±7.6 en ±0.3. Gemerkte N-opname en-verspreiding vir twee- en drie-jaar-oue appelbome is ook gedurende dieselfde seisoen vasgestel. Die gemerkte N-opname en-verspreidings resultate toon dat daar lae gemerkte N opname was gedurende die aanvanklike groeistadiums wat die belangrikheid van interne N reserwes vir plantontwikkeling aan die begin van die seisoen beklemtoon. Gedurende die aktiewe groei-periode is meer as 60% gemerkte N in die nuwe groei gevind. Opnamedoeltreffendheid het verbeter soos die bome ouer geword het. v Die effek van verskillende voedingstofvlakke op boomgroei, opbrengs en vruggehalte is bestudeer; die een laer (80%) as die standaard (100%) en drie hoër (120%, 140% en 160%). Die resultate toon dat die verskillende voedingstofvlakke geen effek op opbrengs, kleur en TOS gedurende die 18 maande oor twee opbrengs-seisoene van die toediening gehad het nie. Die toediening van biologiese produkte (soos humiensuur en kompos plus kompos-ektrak) oor ‘n periode van 18 maande het ‘n groot invloed gehad op die verbetering van TOS, appelsuur en sitroensuur konsentrasie. Daar was ñ tendens van toename in fyn wortel aantal en lengte met die byvoeging van biologiese ameliorante. vi Dedicated to my lovely parents Gersom and Ida Thanks for all the love, support and encouragements vii Nutrient requirement and distribution of intensively grown ‘Brookfield Gala’ apple trees Contents Page Declaration i Summary ii Opsomming iv Dedication vi Nutrient requirements and distribution of intensively grown ‘Brookfield Gala’ apple trees vii Acknowledgements ix General Introduction 1 1. Nutrient uptake and distribution, and management of fruit crops: Literature Review 4 1.1 Introduction 4 1.2 Nutrient Requirements 5 1.2.1 Nitrogen 7 1.2.2 Phosphorus 8 1.2.3 Potassium 8 1.2.4 Calcium 9 1.2.5 Magnesium 10 1.2.6 Sulphur 10 1.2.7 Micro elements 10 1.3 Leaf and soil nutrient concentration 12 1.4 Root studies 13 1.5 Nutrient Uptake 14 1.5.1 Nitrogen 15 1.5.2 Phosphorus 16 1.5.3 Potassium 16 1.5.4 Calcium 17 1.5.5 Magnesium 18 1.5.6 Sulphur 18 1.5.7 Micro elements 18 1.6 Nutrient translocation 20 viii 1.7 Seasonal changes and accumulation of nutrients 20 1.7.1 Nitrogen 20 1.7.2 Phosphorus 22 1.73 Potassium 23 1.7.4 Calcium 23 1.7.5 Magnesium 24 1.7.6 Sulphur 24 1.7.7 Micro nutrients 24 1.8 Organic ameliorants 26 1.8.1 Humic acid 27 1.8.2 Compost 28 1.8.3 Compost extract 29 1.9 Use of labeled nitrogen 29 1.10 Influence of mineral nutrition on fruit quality 31 1.11 References 33 2. Seasonal Uptake, Distribution and Requirements of macro and micro elements by intensively grown apple trees 40 2.1 Seasonal uptake and distribution of macro elements in two and three-year old apple trees 40 2.2 Seasonal uptake and distribution of micro elements in two and three-year old apple trees 67 2.3Guidelines for macro element requirements of young and bearing apple trees 86 2.4 Guidelines for micro element requirements of young and bearing apple trees 98 3. Using 15N enriched fertiliser to optimize N management of young ‘Brookfield Gala’ apple trees 109 4. The influence of different nutrient levels or biological ameliorants on yield, fruit quality, shoot, fruit and root growth of apple trees 129 5. General conclusions 151 6. Appendix 155 ix ACKNOWLEDGEMENTS My sincere gratitude’s go to the following people and institutions: My supervisor, Prof P.J.C Stassen, for his scientific contribution, guidance, patience and motivations My co-supervisor, Prof. K.I Theron, who was always available for consultations, especially with the statistical analyses and interpretations My co-supervisor, Prof R. Rosecrance, who initiated the 15N study Dr. K Conradie for all the help he provide with the 15N study To Marco du Toit who was always ready to help The technical and administrative staff in the Department Horticulture Science The technical and administrative staff in the Department Forestry Science The technical staff in the Department Soil Science To Reenen and Bakenskloof (Rust and Kritzinger) farm for allowing us to run our trials on their farm and all assistance they provided To my colleague Thabiso without your help I could not have managed with all the heavy containers and all the hard physical work involved in my project, thanks a lot To all my colleagues who helped does not matter how small The DAAD Scholarship and the Deciduous Fruit Producers’ Trust for funding the project To all my friends and family members who motivated, supported and encouraged me throughout my studies