objective of this note is to provide basic information and technical

principles needed for the use of the GreenSeeker™,

in agricultural applications such as nitrogen fertilization,

irrigation scheduling, mapping of agricultural fi elds and

precision agriculture. A description of the instrument is provided,

as well as the technical and physiological principles

that support its use in agriculture. The radiative properties

of plant canopies and light refl ection from healthy and

stressed crops are described briefl y. Possible applications of

GreenSeeker in diagnosis and correction of crop disorders

in the fi eld in real time are considered, according to spatial

heterogeneity ubiquitous in tropical agro ecosystems. The

limitations of the technology currently available and its

applications to other tropical crops, besides rice and corn,

are also addressed.

Keywords: NDVI, nitrogen-containing pigments, precision agriculture, radiation, refl ectance, remote sensors.