Estimating Forage Wheat Biomass From 3-D Vegetation Parameters Collected Using a Terrestrial Laser Scanner.

Recent literature suggests new innovative techniques are available for deriving estimations of above ground biomass in forage systems.  Currently, development of wheat cultivars for increased forage production is limited by the inability to accurately and nondestructively phenotype the potential of individual lines in breeding systems.  Terrestrial Laser Scanning (TLS) is a non-destructive method to capture changes in the aboveground 3-D structure and distribution of wheat.  Consequently, our objective was to evaluate the use of TLS to estimate aboveground biomass.  Using a Leica Scan Station 2 time of flight TLS we surveyed a 23m x 46m site at 1cm point spacing resolution and a range of 30m.  The site consisted of 25 nitrogen (N) treatments on one forage wheat variety replicated 4 times for a total of 100 subplots each at 1.5m x 6.0m.  We expected differences in biomass based on N treatments within the subplots.  The survey data was collected at the four corners and midpoints of the two outer lengths of the plot boundary.  The TLS data was processed to generate 3-D visualizations of plant, height, and point density within each subplot.  Whole plot biomass was destructively measured in each subplot by an Alfalfa-Omega flail type forage harvester.  Individual subplots were collected dried and weighted.  An allometric equation was developed by comparison of the acquired TLS plant height and point density to the field biomass measurements to derive a predicted biomass for each subplot.  Within the site the sensor detected differences in aboveground plant biomass across the subplot N treatments.