000K  utf8
1100  $c2022
1500  eng
2050  urn:nbn:de:gbv:8:3-2023-00609-0
2051  10.3390/rs14184525
3000  Holzhauser, Katja
3010  Kage, Henning
3010  Kühling, Insa
3010  Räbiger, Thomas
3010  Rose, Till
4000  Estimation of Biomass and N Uptake in Different Winter Cover Crops from UAV-Based Multispectral Canopy Reflectance Data  [Holzhauser, Katja]
4209  Cover crops are known to provide beneficial effects to agricultural systems such as a reduction in nitrate leaching, erosion control, and an increase in soil organic matter. The monitoring of cover crops’ growth (e.g., green area index (GAI), nitrogen (N) uptake, or dry matter (DM)) using remote sensing techniques allows us to identify the physiological processes involved and to optimise management decisions. Based on the data of a two-year trial (2018, 2019) in Kiel, Northern Germany, the multispectral sensor Sequoia (Parrot) was calibrated to the selected parameters of the winter cover crops oilseed radish, saia oat, spring vetch, and winter rye as sole cover crops and combined in mixtures. Two simple ratios (SRred, SRred edge) and two normalised difference indices (NDred, NDred edge) were calculated and tested for their predicting power. Furthermore, the advantage of the species/mixture–individual compared to the universal models was analysed. SRred best predicted GAI, DM, and N uptake (R2: 0.60, 0.53, 0.45, respectively) in a universal model approach. The canopy parameters of saia oat and spring vetch were estimated by species–individual models, achieving a higher R2 than with the universal model. Comparing mixture–individual models to the universal model revealed low relative error differences below 3%. The findings of the current study serve as a tool for the rapid and inexpensive estimation of cover crops’ canopy parameters that determine environmental services.
4950  https://doi.org/10.3390/rs14184525$xR$3Volltext$534
4950  https://nbn-resolving.org/urn:nbn:de:gbv:8:3-2023-00609-0$xR$3Volltext$534
4961  https://macau.uni-kiel.de/receive/macau_mods_00003932
5051  333.7
5550  catch crops
5550  NDV
5550  Parrot Sequoia
5550  pure and mixed canopies
5550  remote sensing
5550  sensor calibration