Estimation of Biomass and N Uptake in Different Winter Cover Crops from UAV-Based Multispectral Canopy Reflectance Data
Cover crops are known to provide beneficial effects to agricultural systems such as a reduction in nitrate leaching, erosion control, and an increase in soil organic matter. The monitoring of cover crops’ growth (e.g., green area index (GAI), nitrogen (N) uptake, or dry matter (DM)) using remote sen...
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MDPI AG
2022-09-01
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| Series: | Remote Sensing |
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| Online Access: | https://www.mdpi.com/2072-4292/14/18/4525 |
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| author | Katja Holzhauser Thomas Räbiger Till Rose Henning Kage Insa Kühling |
| author_facet | Katja Holzhauser Thomas Räbiger Till Rose Henning Kage Insa Kühling |
| author_sort | Katja Holzhauser |
| collection | DOAJ |
| description | Cover crops are known to provide beneficial effects to agricultural systems such as a reduction in nitrate leaching, erosion control, and an increase in soil organic matter. The monitoring of cover crops’ growth (e.g., green area index (GAI), nitrogen (N) uptake, or dry matter (DM)) using remote sensing techniques allows us to identify the physiological processes involved and to optimise management decisions. Based on the data of a two-year trial (2018, 2019) in Kiel, Northern Germany, the multispectral sensor Sequoia (Parrot) was calibrated to the selected parameters of the winter cover crops oilseed radish, saia oat, spring vetch, and winter rye as sole cover crops and combined in mixtures. Two simple ratios (SR<sub>red</sub>, SR<sub>red edge</sub>) and two normalised difference indices (ND<sub>red</sub>, ND<sub>red edge</sub>) were calculated and tested for their predicting power. Furthermore, the advantage of the species/mixture–individual compared to the universal models was analysed. SR<sub>red</sub> best predicted GAI, DM, and N uptake (R<sup>2</sup>: 0.60, 0.53, 0.45, respectively) in a universal model approach. The canopy parameters of saia oat and spring vetch were estimated by species–individual models, achieving a higher R<sup>2</sup> than with the universal model. Comparing mixture–individual models to the universal model revealed low relative error differences below 3%. The findings of the current study serve as a tool for the rapid and inexpensive estimation of cover crops’ canopy parameters that determine environmental services. |
| first_indexed | 2024-03-09T22:38:20Z |
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| id | doaj.art-075c06c4881a45f98423044420f08014 |
| institution | Directory Open Access Journal |
| issn | 2072-4292 |
| language | English |
| last_indexed | 2024-03-09T22:38:20Z |
| publishDate | 2022-09-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Remote Sensing |
| spelling | doaj.art-075c06c4881a45f98423044420f080142023-11-23T18:44:04ZengMDPI AGRemote Sensing2072-42922022-09-011418452510.3390/rs14184525Estimation of Biomass and N Uptake in Different Winter Cover Crops from UAV-Based Multispectral Canopy Reflectance DataKatja Holzhauser0Thomas Räbiger1Till Rose2Henning Kage3Insa Kühling4Institute of Crop Science and Plant Breeding, Kiel University, 24118 Kiel, GermanyInstitute of Crop Science and Plant Breeding, Kiel University, 24118 Kiel, GermanyInstitute of Crop Science and Plant Breeding, Kiel University, 24118 Kiel, GermanyInstitute of Crop Science and Plant Breeding, Kiel University, 24118 Kiel, GermanyInstitute of Crop Science and Plant Breeding, Kiel University, 24118 Kiel, GermanyCover crops are known to provide beneficial effects to agricultural systems such as a reduction in nitrate leaching, erosion control, and an increase in soil organic matter. The monitoring of cover crops’ growth (e.g., green area index (GAI), nitrogen (N) uptake, or dry matter (DM)) using remote sensing techniques allows us to identify the physiological processes involved and to optimise management decisions. Based on the data of a two-year trial (2018, 2019) in Kiel, Northern Germany, the multispectral sensor Sequoia (Parrot) was calibrated to the selected parameters of the winter cover crops oilseed radish, saia oat, spring vetch, and winter rye as sole cover crops and combined in mixtures. Two simple ratios (SR<sub>red</sub>, SR<sub>red edge</sub>) and two normalised difference indices (ND<sub>red</sub>, ND<sub>red edge</sub>) were calculated and tested for their predicting power. Furthermore, the advantage of the species/mixture–individual compared to the universal models was analysed. SR<sub>red</sub> best predicted GAI, DM, and N uptake (R<sup>2</sup>: 0.60, 0.53, 0.45, respectively) in a universal model approach. The canopy parameters of saia oat and spring vetch were estimated by species–individual models, achieving a higher R<sup>2</sup> than with the universal model. Comparing mixture–individual models to the universal model revealed low relative error differences below 3%. The findings of the current study serve as a tool for the rapid and inexpensive estimation of cover crops’ canopy parameters that determine environmental services.https://www.mdpi.com/2072-4292/14/18/4525remote sensingParrot Sequoiacatch cropssensor calibrationpure and mixed canopiesNDVI |
| spellingShingle | Katja Holzhauser Thomas Räbiger Till Rose Henning Kage Insa Kühling Estimation of Biomass and N Uptake in Different Winter Cover Crops from UAV-Based Multispectral Canopy Reflectance Data Remote Sensing remote sensing Parrot Sequoia catch crops sensor calibration pure and mixed canopies NDVI |
| title | Estimation of Biomass and N Uptake in Different Winter Cover Crops from UAV-Based Multispectral Canopy Reflectance Data |
| title_full | Estimation of Biomass and N Uptake in Different Winter Cover Crops from UAV-Based Multispectral Canopy Reflectance Data |
| title_fullStr | Estimation of Biomass and N Uptake in Different Winter Cover Crops from UAV-Based Multispectral Canopy Reflectance Data |
| title_full_unstemmed | Estimation of Biomass and N Uptake in Different Winter Cover Crops from UAV-Based Multispectral Canopy Reflectance Data |
| title_short | Estimation of Biomass and N Uptake in Different Winter Cover Crops from UAV-Based Multispectral Canopy Reflectance Data |
| title_sort | estimation of biomass and n uptake in different winter cover crops from uav based multispectral canopy reflectance data |
| topic | remote sensing Parrot Sequoia catch crops sensor calibration pure and mixed canopies NDVI |
| url | https://www.mdpi.com/2072-4292/14/18/4525 |
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