In-situ real-time NIR monitoring of nitrogen in irrigated cotton northern NSW, Australia

Achieving optimum yield in cotton (Gossypium hirsutum L.) requires pre-season soil nitrogen analysis and frequent in-crop monitoring. The current agronomic protocol requires petiole sampling at 3 critical stages during early crop development.

Emerging technologies such as handheld near infrared spectrometers (NIRs) in combination with crop models (NutriLOGIC) can provide in-situ analysis of petioles to address nitrogen deficiencies in real-time. Petiole total nitrogen was shown to be accurately measured in-situ via a handheld NIRs. The results were comparable to conventional field petiole sampling and laboratory analysis methods. Therefore, portable near infrared spectrometers are a viable option to monitor in-crop nitrogen in real-time.