Experimental Tests of the Light-Use Efficiency Model in Alfalfa

• Author / Creator

  Castro, Saulo M

• This study explored ways of integrating optical and flux measurements in the context of the Light Use Efficiency (LUE) model in an alfalfa (Medicago sativa) field. Narrow-band spectrometers and low cost two-band radiometers provided alternate ways to measure NDVI and estimate the APAR term of the LUE model. The high temporal resolution of two-band sensors system accurately tracked seasonal carbon flux dynamics (R2 = 0.96) demonstrating the value of automated, low cost approaches to monitoring NDVI and canopy light absorption, which was the dominant term in the LUE model for this agricultural field. At the seasonal scale PRI correlations with LUE varied with the LUE formulation, and suggested that seasonal PRI patterns were primarily driven by canopy structure changes. However, at the diurnal level, ∆PRI correlated with changing efficiency. Combined optical and flux sampling can help partition flux data, gap-fill data, and add insights into the controls of carbon fluxes.

• Subjects / Keywords

  • Sensor Comparison
  • Light-Use Efficiency
  • Eddy Covariance
  • Temporal Aggregation
  • Ecosystem Productivity
  • Photochemically Reflectance Index

• Graduation date

  Fall 2013

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R36W96J0R

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.