The profitability of precision agriculture in the Bothaville district

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dc.contributor.advisorNell, W. T.
dc.contributor.advisorLowenbert-DeBoer, J.
dc.contributor.advisorGudeta, Z.
dc.contributor.authorMaine, Ntsikane
dc.date.accessioned2018-01-11T10:49:34Z
dc.date.available2018-01-11T10:49:34Z
dc.date.issued2006-11
dc.description.abstractEnglish: Variable-rate application technology based on soil potential and other field attributes is gradually replacing the standard rates of fertilizer application for individual cropping systems. In South Africa, differential application of inputs in cash crop production is mainly concerned with fertilizer and lime, and this indicates the importance of these inputs. This study evaluates the maize yield response to variable-rate (VR) application of nitrogen (N), and estimates the profitability of VR application of N relative to single-rate (SR) application under South African conditions. Data was collected from an experimental field of 104 ha on a farm in the Bothaville district. A strip-plot design consisting of 180 strips was used for this on-farm research experiment. This design involved treatments that ran in the same direction across the field as planting and harvesting. The objectives were to determine the maize crop response functions under different N rates, to estimate optimal N rates for different management zones in different years, and to assess profit estimates using ordinary least squares (OLS) and spatial error (SER) models. The methodology involves modelling maize yield response functions for N. A Baseline regression model that analyses variable-rate technology as a package was used, while three sensitivity tests were used to determine the consistency of the estimates. The results of this study indicate that there is a significant variation in maize yield response to the applied N on the basis of the application method used. Profit analysis resulting from the application strategies indicates that, in general, VR results in higher farming profits than SR. The analysis indicates that yield obtained from VR strategy can compensate additional costs incurred with the investment in VR technology. This finding is consistent in all the models. It has been established that yield response to fertilizer depends on soil conditions such as the effective soil depth, which has a positive effect on yield. Yield response also differs among management zones. Differences were observed between the results obtained from the OLS models and the results obtained with the SER models, and this has an impact on decision-making. The importance of taking spatial effects into account came to the fore, as inaccurate results can be obtained with methodologies that ignore the spatial dependencies in the analysis of yield monitor data.en_ZA
dc.description.abstractAfrikaans: Veranderlike-toedieningspeiltegnologie, gebaseer op grondpotensiaal en ander landeienskappe, is besig om die standaardpeile van kunsmistoediening vir individuele gewasstelsels geleidelik te vervang. Differensiële toediening van kontantgewasproduksie-insette fokus in hoofsaak op kunsmis en kalk. Hierdie studie evalueer die mielieopbrengs-reaksie op veranderlike toedieningspeile (VT) van stikstof (N), en beraam die winsgewendheid van VT van N in vergelyking met enkelpeiltoedienings (ET) onder Suid-Afrikaanse toestande. Die data is afkomstig van 'n eksperimentele land van 104 ha op 'n plaas in die Bothaville-distrik. 'n Strookperseelontwerp, bestaande uit 180 stroke, wat in dieselfde rigting as die plant en strooprigting uitgelê is, is gebruik. Die doelstellings was die bepaling van mieliegewas-responsfunksies aan die hand van verskillende N-peile, die beraming van optimale N-peile vir verskillende bestuursones in verskillende jare, en die analisering van boerdery winsskattings met die gebruik van gewone kleinste kwadrate-modelle (GKK-modelle) en ruimtelike fout-modelle (RF-modelle). Die metodologie behels die modellering van mielieopbrengs-responsfunksies vir N. 'n Basislynregressiemodel, wat VT-tegnologie as 'n pakket ontleed, is gebruik, terwyl drie sensitiwiteitstoetse gebruik is om die konsekwentheid van die beramings te bepaal. Die resultate van hierdie studie dui aan dat daar beduidende variasie bestaan ten opsigte van mielieopbrengsreaksie op die toedieningspeile van N, afhangende van die toedieningsmetode (veranderlik of enkel) wat gebruik is. Die winsontleding wat voortspruit uit die toedieningstrategieë toon aan dat VT oor die algemeen hoër winste as ET genereer. Die analise toon aan dat die opbrengs van 'n VT-strategie kan vergoed vir die bykomende koste wat met diebelegging VT tegnologie gepaard gaan. Hierdie bevinding is konsekwent in alle modelle. Daar is verder vasgestel dat die opbrengsrespons op kunsmis afhang van grondtoestande, soos die effektiewe gronddiepte, wat 'n positiewe uitwerking op opbrengs het. Verskillende bestuursones het ook verskillende opbrengsreaksies getoon. Verskille wat waargeneem is tussen die resultate wat met die GKK-modelle behaal is en die resultate wat met die RF-modelle verkry is, het 'n impak op besluitneming gehad. Die noodsaaklikheid om ruimtelike effekte in ag te neem, is beklemtoon aangesien onakkurate resultate behaal kan word met metodologieë wat die ruimtelike afhanklikhede in die ontleding van opbrengsmonitordata ignoreer.af
dc.description.sponsorshipNew Holland South Africaen_ZA
dc.description.sponsorshipAndrew Mellon Foundationen_ZA
dc.identifier.urihttp://hdl.handle.net/11660/7579
dc.language.isoenen_ZA
dc.publisherUniversity of the Free Stateen_ZA
dc.rights.holderUniversity of the Free Stateen_ZA
dc.subjectPrecision agricultureen_ZA
dc.subjectPrecision farmingen_ZA
dc.subjectVariable-rate applicationen_ZA
dc.subjectSingle rate applicationen_ZA
dc.subjectProfitabilityen_ZA
dc.subjectSpatial error modelen_ZA
dc.subjectNitrogenen_ZA
dc.subjectSouth Africaen_ZA
dc.subjectPrecision farming -- South Africa -- Bothavilleen_ZA
dc.subjectCorn -- South Africa -- Bothavilleen_ZA
dc.subjectNitrogen fertilizersen_ZA
dc.subjectThesis (Ph.D. (Agriculture Economics (Centre for Agricultural Management))--University of the Free State, 2006en_ZA
dc.titleThe profitability of precision agriculture in the Bothaville districten_ZA
dc.typeThesisen_ZA
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