Predicting N Status in Maize with Clip Sensors: Choosing Sensor, Leaf Sampling Point, and Timing

Area of Science:

• Agricultural Science
• Agronomy
• Soil Science

Background:

• Nitrogen (N) losses from agriculture contribute to environmental pollution, often linked to excessive N fertilization.
• Optimizing N fertilization is essential for improving fertilizer use efficiency and mitigating environmental impacts.
• Leaf clip sensors offer a potential tool for real-time assessment of plant N status.

Purpose of the Study:

• To evaluate the efficacy of leaf clip chlorophyll sensors for identifying maize nitrogen status and predicting yield.
• To compare the performance of two different sensor devices (SPAD-502® and Dualex®).
• To determine the optimal leaf sampling protocol for accurate maize N status assessment.

Main Methods:

• Conducted five field experiments in Central Spain.
• Utilized SPAD-502® and Dualex® leaf clip sensors to measure chlorophyll content.
• Analyzed polyphenol (flavonol) data in conjunction with chlorophyll measurements.
• Investigated the impact of sampling position and timing on N status estimation.

Main Results:

• Both SPAD-502® and Dualex® sensors showed similar performance in assessing maize N status, with minor differences at high N concentrations.
• Incorporating polyphenol (flavonol) data improved the prediction of N deficiency.
• Established that leaf and plant sampling position, along with sampling time, are critical factors for accurate N status estimation.

Conclusions:

• Leaf clip chlorophyll sensors are effective tools for identifying maize N status and can aid in yield prediction.
• Complementary polyphenol measurements enhance the accuracy of N deficiency detection.
• Defined optimal sampling strategies for reliable N status assessment, enabling precise fertilization recommendations.