Data/hora: 16/06/2024 10:28:01

Provedor de dados: 	70	
País: 	Brazil	
Título: 	EFFECT OF HEIGHT, TILT AND TWIST ANGLES OF AN ACTIVE REFLECTANCE SENSOR ON NDVI MEASUREMENTS	
Autores: 	Stocker,Vinícius; Souza,Eduardo G. de; Johann,Jerry A.; Beneduzzi,Humberto M.; Silva,Franciléia de O. e.	
Data: 	2019-09-01	
Ano: 	2019	
Palavras-chave: 	Nitrogen fertilization; Precision agriculture; GreenSeeker; NDVI.	
Resumo: 	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, and took NDVI readings in stages R2 and R5. Our goal was to study the effects of the position of an active reflectance sensor (GreenSeeker) on the NDVI index at different heights and at different angles to the canopy. We observed that the height of the sensor affected the NDVI depending on the stage of the plant and that angles up to 15° of the sensor did not directly affect the readings.	
Tipo: 	Info:eu-repo/semantics/article	
Idioma: 	Inglês	
Identificador: 	http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162019000800096	
Editor: 	Associação Brasileira de Engenharia Agrícola	
Relação: 	10.1590/1809-4430-eng.agric.v39nep96-108/2019	
Formato: 	text/html	
Fonte: 	Engenharia Agrícola  v.39 n.spe 2019	
Fonte: 	info:eu-repo/semantics/openAccess