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Using an Active Sensor to Develop New Critical Nitrogen Dilution Curve for Winter Wheat
Jie Jiang1, Cuicun Wang1, Yu Wang1
1National Engineering and Technology Center for Information Agriculture, MOE Engineering and Research Center for Smart Agriculture, Key Laboratory for Crop System Analysis and Decision Making, Ministry of Agriculture, Jiangsu Key Laboratory for Information Agriculture, Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University, 1 Weigang Road, Nanjing 210095, China.
A new method uses the normalized difference red-edge (NDRE) index to create critical nitrogen (N) dilution curves (CNDCs) for wheat. This approach offers a faster, cheaper, and accurate way to assess plant nitrogen status and guide in-season N management.
Area of Science:
- Agronomy
- Plant Physiology
- Remote Sensing
Background:
- Critical nitrogen (N) dilution curves (CNDCs) are essential for diagnosing plant N status.
- Traditional CNDC determination relies on plant dry matter (PDM), which can be labor-intensive.
- Developing convenient alternatives for CNDC assessment is crucial for efficient crop management.
Purpose of the Study:
- To develop and validate a novel, convenient method for determining winter wheat CNDCs using remote sensing data.
- To compare the precision of the new NDRE-based CNDC with the traditional PDM-based CNDC.
- To evaluate the utility of the NDRE-based CNDC for in-season nitrogen management and yield prediction.
Main Methods:
- Conducted four field experiments with varying N rates and wheat varieties from 2014-2019.
- Utilized the normalized difference red-edge (NDRE) index from a RapidSCAN sensor as a proxy for PDM.
- Established a new CNDC equation based on NDRE: Nc = 0.90NDRE-0.88 (for NDRE ≤ 0.19) and constant Nc = 3.81% (for NDRE > 0.19).
Main Results:
- The NDRE-derived CNDC (R2 = 0.76) showed comparable precision to the PDM-derived CNDC (R2 = 0.73).
- Both methods accurately discriminated wheat nitrogen status.
- The NDRE-based CNDC demonstrated strong correlations with grain yield at jointing (R2 = 0.79) and booting (R2 = 0.87) stages.
Conclusions:
- The NDRE-based CNDC provides an effective, non-destructive, and cost-efficient alternative for diagnosing wheat nitrogen status.
- This method facilitates rapid and accurate in-season nitrogen management decisions.
- The NDRE-based CNDC holds significant potential for optimizing nitrogen fertilization in wheat production.
