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dc.contributor.advisorDu Preez, C. C.
dc.contributor.advisorCeronio, G. M.
dc.contributor.authorWessels, C. F.
dc.date.accessioned2015-09-03T09:06:33Z
dc.date.available2015-09-03T09:06:33Z
dc.date.issued2014
dc.identifier.urihttp://hdl.handle.net/11660/1140
dc.description.abstractEnglish: Maize in Southern Africa is the most important crop for animal and human nutrition. Soil fertility, its management and understanding have an unmistakable role to play in modern agriculture. Maize is prone to zinc deficiency and is known to decrease yield as well as lowering nutritional value. Zinc is reported to be one of the most important micronutrients for the growth and development of maize. An incubation and glasshouse experiment was conducted to evaluate the response of plant available zinc in sandy soil when fertilized with ZnSO4, ZnO and ZnEDTA at different rates. For this purpose a range of extractants were used: HCl, Mehlich I, DTPA, EDTA and Ambic II. In the incubation experiment, two almost similar sandy soils differing only in acidity were treated with the three zinc fertilizers to increase the zinc content with 0 mg kg-1, 1 mg kg-1, 2 mg kg-1, 3 mg kg-1 and 4 mg kg-1. Each treatment was repeated five times. Fertilizers were applied as a solution, and after application soil went through three wetting and drying cycles before plant available zinc was determined in them. In the mentioned glasshouse experiment maize was planted in 40.5 L pots using a complete randomized block design. The same zinc fertilizers were used as for the incubation experiment but application rates differed. One of the soils used for the incubation experiment was selected and treated to increase its zinc content with 0 mg kg-1, 0.5 mg kg-1, 1 mg kg-1, 2 mg kg-1 and 4 mg kg-1. Phosphorus and nitrogen were added to the soil at a constant rate. Fertilizers were dissolved in water and applied as a solution on soil before thoroughly mixed. Maize were planted 50 mm deep and soil was maintained at drained upper limit during the growing period. During the five week growing period stem thickness, plant height and number of leaves were measured weekly while leaf area, root length, root mass and plant available zinc were measured at the end of the growing period. The experiment was repeated at two planting dates. After the growing period soil was sampled for zinc and phosphorus analysis. Concerning zinc source used, ZnSO4 was superior followed by ZnEDTA and ZnO in most of the measured plant parameters as well as plant available zinc content. Plant available zinc content at the end of the incubation experiment differed between the two soils. Extraction methods used to determine plant available zinc content led to different values. For both soils used in the incubation experiment Ambic II, DTPA and EDTA tend to extract more zinc than HCl and Mehlich I. Zinc fertilizers and application rates had a significant effect on plant parameters in the glasshouse experiment. The two plantings differed from each other. The effect of ZnO and ZnEDTA on aerial and subsoil growth parameters was not consistent throughout the glasshouse experiment. Most of the plant parameters showed an impaired development at increasing application rates. This phenomenon however did not occur in the plant available zinc content at the end of the growing period. Extraction method used to determine plant available zinc content at the end of the glasshouse experiment differed. However, the order differs from the results obtained in the incubation experiment. For both experiments the Ambic II and EDTA methods tend to extract the highest amount of zinc from the soil. Zinc source and application rate had a significant effect on both the concentration and uptake of zinc in/by maize. Again ZnSO4 was superior in increasing uptake and concentration of zinc by/in maize, with ZnO and ZnEDTA being inconsistent. Considering the reasons for this study it is clear that ZnSO4 was superior over ZnO and ZnEDTA. This could be attributed that with ZnEDTA and ZnO there were no compensation for the S in ZnSO4. Furthermore the ZnEDTA used was synthetically prepared and may be less effective than natural products. Zinc fertilizer and application rate also proved to have an effect on plant available zinc content and maize growth response.en_ZA
dc.description.abstractAfrikaans: Mielies is die belangrikste gewas in Suidelike Afrika vir die voeding van mens en dier. Grondvrugbaarheid, die bestuur en begrip daarvan het daarom „n onmisbare rol in moderne landbou. Mielies is sensitief vir sinktekorte en word gekenmerk deur verlaagde opbrengs sowel as laer voedingswaarde van grane. Daar word berig dat sink een van die belangrikste mikro-elemente vir die groei en ontwikkeling van mielies is. ‟n Inkubasie- en glashuiseksperiment is uitgevoer om die reaksie van plantbeskikbare sink in sandgrond wanneer bemes word met ZnSO4, ZnO en ZnEDTA teen verskillende peile te ondersoek. Vir die doel is ‟n reeks ektraheermiddels gebruik: HCl, Mehlich I, DTPA, EDTA en Ambic II. In die inkubasie-eksperiment is twee soortgelyke sandgronde, wat slegs verskil in suurheid, behandel met die drie sinkbemestingstowwe om die sinkinhoud van die grond te verhoog met 0 mg kg-1, 1 mg kg-1, 2 mg kg-1, 3 mg kg-1 en 4 mg kg-1. Elke behandeling is vyf keer herhaal. Bemestingstowwe is toegedien as „n oplossing en na toedienning het die grond deur drie benatting- en drogingsiklusse gegaan voor plantbeskikbare sink daarin bepaal is. In die bogenoemde glashuiseksperiment is mielies geplant in 40.5 L potte deur ‟n volledige ewekansige blok ontwerp te gebruik. Dieselfde sinkbemestingstowwe as vir die inkubasie-eksperiment is gebruik maar toedieningspeile het wel verskil. Slegs een van die gronde in die inkubasie-ekperiment is vir die glashuiseksperiment gebruik en dié se sinkinhoud is met 0 mg kg-1, 0.5 mg kg-1, 1 mg kg-1, 2 mg kg-1 en 4 mg kg-1 verhoog. Die grond is ook met fosfor en stikstof teen ‟n konstante peil bemes. Alle kunsmis is opgelos in water voordat dit aan die grond toegedien is, daarna is grond deeglik gemeng. Mieliesaad is in die middel van die pot 50 mm diep geplant. Gedurende die eksperiment is grond nat gehou teen die boonste grens van plantbeskikbare water. Stamdikte, planthoogte en aantal blare is op ‟n weeklikse basis gemeet gedurende die vyf week groeiperiode terwyl blaaroppervlakte, wortellengte, wortelmassa en plantbeskikbare sink aan die einde van die groeiperiode bepaal is. Na die groeiperiode is grondmonsters gebruik vir fosfaat en sink ontledings. Vir die meeste plantparameters het ZnSO4 beter gedoen, gevolg deur ZnEDTA en ZnO. Plantbeskikbare sink aan die einde van die inkubasie-eksperiment het verskil tussen die twee gronde. Ekstraksiemetodes wat gebruik is vir die bepaling van plantbeskikbare sink het tot verskillende waardes gelei. Vir beide die gronde in die inkubasie-ekperiment het Ambic II, DTPA en EDTA meer plantbeskikbare sink ge-ekstraheer as HCl en Mehlich I. Sinkbemestingstowwe en toedieningspeile het ‟n betekenisvolle effek op plantparameters in die glashuiseksperiment gehad. Die twee plantdatums het ook betekenisvol van mekaar verskil. Die effek van ZnO en ZnEDTA op bo- en ondergrondse groeiparameters was nie konstant gedurende die glashuisekperiment nie. Meeste van die plantparameters het swakker ontwikkeling getoon met „n toename in toedienningspeile. Hierdie verskynsel het egter nie voorgekom in die plantbeskikbare sink aan die einde van die groeiperiode nie. Daar was wel betekenisvolle verskille tussen ekstraksiemetodes wat gebruik is vir die bepaling van plantbeskikbare sink aan die einde van die glashuiseksperiment. Die volgorde het egter verskil van dié in die inkubasie-eksperiment. Vir beide die eksperimente het dié Ambic II en EDTA metodes groter hoeveelhede sink ge-ekstraheer vanuit die grond. Sinkbron en toedienningspeil het ‟n betekenisvolle effek op beide die konsentrasie en opname van sink in/deur mielies getoon. Weereens was ZnSO4 beter betreffende die opname en konsentrasie van sink in/deur mielies, met ZnO en ZnEDTA wat nie ‟n konstante reaksie getoon het nie. Na aanleiding van die redes vir hierdie studie is dit duidelik dat ZnSO4 beter was as ZnO en ZnEDTA. Dit sou toegeskryf kan word dat met ZnEDTA en ZnO daar geen kompensasie was vir die S in ZnSO4. Verder is sinteties bereide ZnEDTA gebruik wat minder effektief mag wees as natuurlike produkte. Sinkbemestingstof en toedienningspeil het wel ‟n effek op plantbeskikbare sink en mielie-ontwikkeling gehad.af
dc.language.isoenen_ZA
dc.publisherUniversity of the Free Stateen_ZA
dc.subjectZinc sourceen_ZA
dc.subjectExtraction methoden_ZA
dc.subjectPlant parametersen_ZA
dc.subjectUptakeen_ZA
dc.subjectConcentrationen_ZA
dc.subjectDissertation (M.Sc.Agric. (Soil, Crop and Climate Sciences)--University of the Free State, 2014en_ZA
dc.subjectFertilizers -- Africa, Southernen_ZA
dc.subjectCorn as feeden_ZA
dc.subjectSoil fertility and fertilizers.en_ZA
dc.titleResponse of a sandy soil and maize plants to zinc fertilizersen_ZA
dc.typeDissertationen_ZA
dc.rights.holderUniversity of the Free Stateen_ZA


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