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In-season Diagnosis of Rice Nitrogen Status Using an Active Canopy Sensor

¹Y. Yao, ¹Y. Miao, ²S. Huang, ²M. L. Gnyp, ³R. Khosla, ¹R. Jiang, ²G. Bareth

1. China Agricultural University
2. University of Cologne
3. Colorado State University

Timely non-destructive estimation of crop nitrogen (N) status is crucial for in-season site-specific N management. Active crop canopy sensor is a promising tool to obtain the needed information. The objective of this study was to evaluate GreenSeeker sensor for estimating rice N status at different growth stages. Nitrogen rate experiments were conducted in 2008 and 2009, in Jiansanjiang, Heilongjiang Province, Northeast China. Both experiments used randomized block design with four or three replications and five N rate treatments: 0, 35, 70, 105 and 140 kg N/ha. The N fertilizers were split into three applications: 45% before transplanting, 20% at tillering stage, and 35% at panicle initiation stage. In order to estimate rice yield potential without N application at panicle elongation, each plot was split into two parts: 10m x 10m as the main plot, and 5m x 10m as the split plot without receiving the third N application. An active crop canopy sensor, GreenSeeker was used to collect rice canopy reflectance data across the growing season. The relationships between GreenSeeker sensor data and plant N concentration, biomass, LAI, plant N uptake, nitrogen nutrition index (NNI) will be determined, and response index (RI) will be evaluated for diagnosing rice responsiveness to additional N application.

Keyword: GreenSeeker sensor, Nitrogen nutrition index, Response index, In-season N management

Y. Yao Y. Miao S. Huang M. L. Gnyp R. Khosla R. Jiang G. Bareth Sensor Application in Managing In-season Crop Variability Poster 2012

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