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| KAPP JUNIOR,CLAUDIO; GUIMARÃES,ALAINE M.; CAIRES,EDUARDO F.. |
| ABSTRACT Spectral reflectance sensors may be useful in discriminating biomass and nitrogen status in plants. A field experiment was carried out on a loamy Typic Hapludox under no-tillage in Ponta Grossa, Parana State, Brazil, aiming to evaluate the efficiency of active canopy sensors (GreenSeeker 505 and Crop Circle ACS-470) to discriminate wheat response to nitrogen fertilization by determining the dry mass, nitrogen status, and grain yield. A randomized complete block design was used and four treatments were replicated 12 times. The treatments consisted of nitrogen application, as urea, at the rates of 0, 50, 100, and 150 kg ha-1. The nitrogen rates were applied in topdressing at tillering of wheat crop. The readings from the sensors were sensitive to... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Triticum aestivum L.; GreenSeeker; Crop Circle; NDVI. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162016000500886 |
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| Stocker,Vinícius; Souza,Eduardo G. de; Johann,Jerry A.; Beneduzzi,Humberto M.; Silva,Franciléia de O. e. |
| ABSTRACT The application of nitrogen (N) fertilizer is complex and expensive, so its correct management has financial and environmental benefits. The use of optical proximity sensors is a promising technique. However, the movement of the agricultural machinery or of the person carrying the sensor will result in height differences and/or different tilt and twist angles with respect to the canopy. We considered whether these variations would affect the reflectance measurement. In this study, we took normalized difference vegetation index (NDVI) readings of a wheat canopy, to which 90 kg ha-1 of urea had been applied in stage 5, and observed the NDVI in stages 6, 8 and 10.5. We also tested soybeans, to which 90 kg ha-1 of urea had been applied in stage R1,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Nitrogen fertilization; Precision agriculture; GreenSeeker; NDVI. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162019000800096 |
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