© 1986 Heron Publishing—Victoria, Canada
Determining nitrogen status of young loblolly pine by leaf reflectance
Vernon L. Nelson, Dean H. Gjerstad and Glenn R. Glover
School of Forestry, Alabama Agricultural Experiment Station, Auburn University, AL 36849-4201, USA / Received August 6, 1986
Summary
Five-year-old lobloliy pine (Pinus taeda L.) seedlings were grown in sand culture in a completely randomized experimental design with eight nitrogen concentrations
and three replications. Nitrogen concentration in the nutrient solution varied from 2 to 400 ppm. After a full growing season
under treatment, percent reflectance of sunlight by new foliage was determined. Foliar samples were analyzed for nitrogen
and chlorophyll.
There was a strong positive correlation between nitrogen content and chlorophyll content (r = 0.895). The natural logarithm of percent reflectance was negatively correlated with both percent nitrogen content (r = –0.845) and chlorophyll content (r = –0.838). From these results, prediction equations for estimating nitrogen and chlorophyll content, as a function of reflectance,
were formulated by regression analysis.
