Estimating Sward Forage Mass and Crude Protein with a Moving Plate and Greenseeker®.

Measurement of forage mass (FM) should be an integral part of grazing management, but forage quality should also be considered.  A forage estimator that uses a mobile rising plate to estimate FM of pastures was combined with a Greenseeker^® instrument that measures NDVI.  Plate height and NDVI were used in multiple regressions to predict forage crude protein (CP) in bermudagrass, smooth bromegrass and tall fescue pastures.  Bermudagrass pasture FM harvested in August was closely related (r=0.98) with average plate height.  The equation including factors for plate height and NDVI corresponded closely (r>0.99) with CP sampled from the pastures.  Smooth bromegrass CP estimated by the same process in pastures throughout the season was less precise (r=0.87), possibly because of sward changes at different growth stages.  Tall fescue CP was not related to sward NDVI over the four sampling times of the season.