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Simulating nitrogen dynamics in sugarcane cropping systems using DSSAT-Canegro
Dissertation (MSc)--University of Pretoria, 2016.
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| Format: | Thesis |
| Language: | English |
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University of Pretoria
2016
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| _version_ | 1867613507082518528 |
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| access_status_str | Open Access |
| author2 | Van der Laan, Michael |
| author_browse | Van der Laan, Michael |
| author_facet | Van der Laan, Michael |
| collection | Thesis |
| dc_rights_str_mv | © 2016, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. |
| description | Dissertation (MSc)--University of Pretoria, 2016. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/53523 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:37:14.671Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2016 |
| publishDateRange | 2016 |
| publishDateSort | 2016 |
| publisher | University of Pretoria |
| publisherStr | University of Pretoria |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/53523 Simulating nitrogen dynamics in sugarcane cropping systems using DSSAT-Canegro Van der Laan, Michael u11375176@tuks.co.za Annandale, John George Matlaletsa, Tsoelipe Samuel UCTD Dissertation (MSc)--University of Pretoria, 2016. Sugarcane is a high-biomass producing crop and often requires substantial amounts of nitrogen (N) fertiliser to achieve optimal yields. Nitrogen fertiliser represents a significant input cost for the sugar industry. This nutrient is highly challenging to manage due to its susceptibility to various kinds of losses following application, for example, leaching and denitrification. In addition to reduced profitability, N losses potentially lead to environmental degradation, for example, through eutrophication of water bodies. As a result of the complexities of N dynamics in sugarcane cropping systems, mechanistic crop models are now more commonly being used to help understand these various N inand outflows, and to inform better management practices. These models first require extensive calibration, testing and validation with measured data in order to gain confidence in their performance, however. In this study, a historical dataset from a fertigation trial conducted in Komatipoort, Mpumalanga, was firstly used to assess the ability of DSSAT-Canegro (with a newly included N subroutine) to simulate cane and sucrose yields as well as aboveground N mass in response to different N fertiliser rates over five consecutive seasons (2003-2007). Cane and sucrose yields, as well as aboveground N mass were adequately simulated in response to various N rates under drip irrigation. In addition to this, cane yield, aboveground N mass and soil water N concentrations were monitored for model testing purposes as part of this study in trials conducted in Pongola (irrigated), Mount Edgecombe (rainfed), and Inanda (rainfed), all in KwaZulu Natal. For the Mount Edgecombe trial, N fertiliser treatments that took soil N levels into account before deciding when to fertilise were included, and the potentially reduced leaching loads were investigated by the model. In most cases, the DSSATCanegro model simulated N dynamics and cane yield adequately under both irrigated and rainfed conditions. The model was also observed to perform well under contrasting environmental conditions, such as during periods of drought versus high rainfall. In a number of cases, significant differences in cane yield between treatments receiving different rates of N were not observed in the measured data, indicating that the crop was able to acquire sufficient N from organic matter mineralisation and fertiliser N from previous seasons applications or the different N rates were all more than the required amount. Based on the potential implications of reduced cane yield following water stress and/or N stress, and unwanted N exports to the environment, it is concluded that DSSAT-Canegro is a useful tool to improve our knowledge of N dynamics in sugarcane ropping systems and to develop best management practices. Plant Production and Soil Science MSc Unrestricted 2016-07-01T10:33:16Z 2016-07-01T10:33:16Z 2016-04-15 2016 Dissertation Matlaletsa, TS 2016, Simulating nitrogen dynamics in sugarcane cropping systems using DSSAT-Canegro, MSc Dissertation, University of Pretoria, Pretoria, viewed yymmdd <http://hdl.handle.net/2263/53523> A2016 http://hdl.handle.net/2263/53523 en © 2016, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria |
| spellingShingle | UCTD Simulating nitrogen dynamics in sugarcane cropping systems using DSSAT-Canegro |
| title | Simulating nitrogen dynamics in sugarcane cropping systems using DSSAT-Canegro |
| title_full | Simulating nitrogen dynamics in sugarcane cropping systems using DSSAT-Canegro |
| title_fullStr | Simulating nitrogen dynamics in sugarcane cropping systems using DSSAT-Canegro |
| title_full_unstemmed | Simulating nitrogen dynamics in sugarcane cropping systems using DSSAT-Canegro |
| title_short | Simulating nitrogen dynamics in sugarcane cropping systems using DSSAT-Canegro |
| title_sort | simulating nitrogen dynamics in sugarcane cropping systems using dssat canegro |
| topic | UCTD |
| url | http://hdl.handle.net/2263/53523 |