TEMPORAL VARIABILITY IN ACTIVE REFLECTANCE SENSOR-MEASURED NDVI IN SOYBEAN AND WHEAT CROPS
| Autor: | Humberto Martins Beneduzzi, Claudio Leones Bazzi, Eduardo Godoy de Souza, Kelyn Schenatto |
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| Rok vydání: | 2017 |
| Předmět: |
0106 biological sciences
Pyranometer NDVI Agriculture (General) Cloud cover 01 natural sciences Normalized Difference Vegetation Index S1-972 remote sensing N management Remote sensing precision agriculture food and beverages 04 agricultural and veterinary sciences Agricultural and Biological Sciences (miscellaneous) Reflectivity Nitrogen fertilizer Agronomy 040103 agronomy & agriculture 0401 agriculture forestry and fisheries Environmental science Precision agriculture Vegetation Index vegetation index 010606 plant biology & botany |
| Zdroj: | Engenharia Agrícola, Vol 37, Iss 4, Pp 771-781 (2017) Engenharia Agrícola, Volume: 37, Issue: 4, Pages: 771-781, Published: AUG 2017 Engenharia Agrícola v.37 n.4 2017 Engenharia Agrícola Associação Brasileira de Engenharia Agrícola (SBEA) instacron:SBEA |
| ISSN: | 0100-6916 |
| DOI: | 10.1590/1809-4430-eng.agric.v37n4p771-781/2017 |
| Popis: | Optimization of N management is one of the great challenges to be overcome in grain production, as it is directly related to productivity and can also cause environmental damage. Precision agriculture aims to solve this problem by applying nitrogen fertilizer at varying rates. Reflectance sensors are instruments capable of estimating N needs in various crops, including grain crops. However, it is not clear how these sensors perform under varying solar radiation and cloud cover, due to a lack of research on their temporal variability. Thus, this study examined the temporal variability of the NDVI (normalized difference vegetation index), as measured by an active reflectance sensor, in both soybean and wheat crops. The NDVI data were collected using a GreenSeeker sensor every 15 minutes over 12 or 14 consecutive hours. Incident solar radiation was recorded using an Instrutherm MES-100 pyranometer. In all experiments in soybean and wheat, NDVI was negatively influenced by irradiation, showing higher values at the beginning and end of the day. Changes in cloud cover also affected NDVI values during the experiments. |
| Databáze: | OpenAIRE |
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