Estimating Nitrogen Content of Sweet Pepper Leaves by Reflectance Measurements1

Authors:
  • JTJ. R. Thomas
    J. R. Thomas
Publisher website
Google Scholar
Abstract
A study was conducted to determine the feasibility of using spectrophotometrically measured diffuse light reflectance from top (adaxial) leaf surfaces of sweet pepper (Capsicum annum, L. var. ‘Yolo Wonder’) leaves to quickly estimate their N status. Reflectance was found to be inversely correlated (p = 0.01) with the leaf N content. Regression equations expressing reflectance as a function of leaf N content of greenhouse‐grown sweet peppers were used to estimate the N content of fieldgrown sweet peppers. The difference between Kjeldahldetermined and reflectance‐estimated N contents was less than 0.7%. The regression equation at the 550‐nm wavelength suggests that near the 4% N level a 1% change in reflectance would change the predicted N content by 0.2%. Results show that leaf reflectance can be used to quickly estimate the N status of sweet peppers.
Keywords