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Developing procedures for irrigation management of potatoes (Solanum tuberosum. L) using remote sensing-based crop coefficients, evapotranspiration and weather data
Thesis (MScAgric)--Stellenbosch University, 2025.
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Stellenbosch : Stellenbosch University
2025
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| _version_ | 1867613955484024832 |
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| access_status_str | Open Access |
| author | Hols, Reinhard Willem Brieers |
| author2 | Kempen, Estelle |
| author_browse | Hols, Reinhard Willem Brieers Kempen, Estelle |
| author_facet | Kempen, Estelle Hols, Reinhard Willem Brieers |
| author_sort | Hols, Reinhard Willem Brieers |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MScAgric)--Stellenbosch University, 2025. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/132438 |
| institution | Stellenbosch University (South Africa) |
| last_indexed | 2026-06-10T12:44:21.913Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2025 |
| publishDateRange | 2025 |
| publishDateSort | 2025 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/132438 Developing procedures for irrigation management of potatoes (Solanum tuberosum. L) using remote sensing-based crop coefficients, evapotranspiration and weather data Hols, Reinhard Willem Brieers Kempen, Estelle Swanepoel, Pieter Andreas Steyn, Martin Stellenbosch University. Faculty of AgriSciences. Dept. of Agronomy. Potatoes -- Breeding -- South Africa Crop coefficients -- Remote sensing Evapotranspiration Plants -- Water requirements Irrigation -- Management -- Technological innovations Remote sensing -- Data processing UCTD Thesis (MScAgric)--Stellenbosch University, 2025. Hols, R. W. B. 2025. Developing procedures for irrigation management of potatoes (Solanum tuberosum. L) using remote sensing-based crop coefficients, evapotranspiration and weather data. Unpublished masters thesis. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/8f16ac4d-7e28-4829-a208-6e4c6a2a52a5 ENGLISH ABSTRACT: Efficient irrigation management is essential for sustainable agriculture, especially in water scarce regions like the Sandveld in the Western Cape. Accurate estimation of crop coefficients (Kc) and evapotranspiration (ET) is fundamental for optimizing irrigation. Normalised difference vegetation indices (NDVI), leaf area index (LAI) and green canopy cover (GCC%) have previously been used in different crop types and were demonstrated to be successful in estimating basal crop coefficients (Kcb) and ET. However, the potential of using these remote sensing techniques to improve water management in irrigated potatoes (Solanum tuberosum L.) has yet to be investigated. The aim of this study was to develop remote sensing -based Kc’s for potatoes to facilitate irrigation water management. The study was conducted during the 2023 summer growing season. Five trial sites were identified in the Sandveld region and planted with potato cultivars Mondial, FL2108, Sifra, and Lanorma. The study assessed the use of remote sensing techniques, canopy cover and Kcb in combination with weather data and infield measurements as a viable method to estimate Kc’s and ET, which were then compared with the FAO-56 approach. Drainage was measured using G3 Drain Gauges and soil water content (SWC) was monitored usings capacitance sensors. Rain gauges recorded rainfall and pressure transducers monitored irrigation amounts. Two Eddy-Covariance (ECV) systems were installed in Fields 2 and 5 monitoring H₂0 and CO₂ fluxes. Infield measurements were taken around four sampling points in each field. The measurements included fractional interception of photosynthetically active radiation (FIPAR) using a AccuPAR LP-80 Ceptometer and canopy cover (GCC%) measurements using the Canopeo® mobile application. Plant sampling was conducted through the growing season and destructive growth analysis was performed. Satellite images at 5-day intervals were derived from the Sentinel-2 satellite. Substantial rainfall, ranging between 72 and 118 mm, was recorded during the early stages of the growing season for Fields 1-3, as the Western Cape province experienced a very wet winter and spring in 2023. This led to early drainage and variations in the total seasonal water inputs across the different fields, which was also reflected in differences in irrigation amounts applied (18 -120 mm, respectively). Good linear correlations between NDVI and GCC% and NDVI and FIPAR were obtained with average R² values of 0.98 and 0.93 respectively. On average Kc_FAO- 56 values were 0.15 lower than the Kc_NDVI values during the initial stage of the growing season, while being 0.11, 0.17 and 0.12 higher during the development-, mid-, and end-season stages. Average Kc_NDVI and Kc_ECV values aligned closely with each other, estimating similar mid-season Kc values of 0.98. Average ET_NDVI and ET_ECV values were closely related (146 and 414.3 mm), while the ET_FAO-56 approach overestimated seasonal ET. Furthermore, the comparison between ET_NDVI and ET_ECV produced RMSE and MAE values of 0.8 mm day⁻¹ and 0.57 mm day⁻¹ which outperformed other estimation methods. The results of this study indicate that remotely sensed phenology information offers a more dynamic and accurate approach in the real-time development of Kc values and ET estimation, compared to the FAO-56 approach for potato production in the Sandveld. AFRIKAANSE OPSOMMING: Geen opsomming beskikbaar. Masters 2025-06-06T13:41:36Z 2025-06-06T13:41:36Z 2025-03 Thesis https://scholar.sun.ac.za/handle/10019.1/132438 Stellenbosch University xvi, 138 pages : illustrations, maps application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Potatoes -- Breeding -- South Africa Crop coefficients -- Remote sensing Evapotranspiration Plants -- Water requirements Irrigation -- Management -- Technological innovations Remote sensing -- Data processing UCTD Hols, Reinhard Willem Brieers Developing procedures for irrigation management of potatoes (Solanum tuberosum. L) using remote sensing-based crop coefficients, evapotranspiration and weather data |
| title | Developing procedures for irrigation management of potatoes (Solanum tuberosum. L) using remote sensing-based crop coefficients, evapotranspiration and weather data |
| title_full | Developing procedures for irrigation management of potatoes (Solanum tuberosum. L) using remote sensing-based crop coefficients, evapotranspiration and weather data |
| title_fullStr | Developing procedures for irrigation management of potatoes (Solanum tuberosum. L) using remote sensing-based crop coefficients, evapotranspiration and weather data |
| title_full_unstemmed | Developing procedures for irrigation management of potatoes (Solanum tuberosum. L) using remote sensing-based crop coefficients, evapotranspiration and weather data |
| title_short | Developing procedures for irrigation management of potatoes (Solanum tuberosum. L) using remote sensing-based crop coefficients, evapotranspiration and weather data |
| title_sort | developing procedures for irrigation management of potatoes solanum tuberosum l using remote sensing based crop coefficients evapotranspiration and weather data |
| topic | Potatoes -- Breeding -- South Africa Crop coefficients -- Remote sensing Evapotranspiration Plants -- Water requirements Irrigation -- Management -- Technological innovations Remote sensing -- Data processing UCTD |
| url | https://scholar.sun.ac.za/handle/10019.1/132438 |
| work_keys_str_mv | AT holsreinhardwillembrieers developingproceduresforirrigationmanagementofpotatoessolanumtuberosumlusingremotesensingbasedcropcoefficientsevapotranspirationandweatherdata |