Open AccessEvaluation of a Rising Plate Meter for Use in Multispecies Swards
Author(s) -
Dillard S. Leanne,
Hafla Aimee N.,
Rubano Melissa D.,
Stout Robert C.,
Brito André F.,
Soder Kathy J.
Publication year - 2016
Publication title -
agricultural and environmental letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.681
H-Index - 12
ISSN - 2471-9625
DOI - 10.2134/ael2016.08.0032
Subject(s) - calibration , polynomial regression , forage , linear regression , mathematics , regression analysis , regression , statistics , metre , polynomial , zoology , environmental science , ecology , mathematical analysis , biology , physics , astronomy
Core Ideas The accuracy of rising plate meter in multispecies swards has not been tested thoroughly. Forcing X intercept to zero increases the precision of the calibration equations. Higher‐order polynomial regressions do not result in more accurate forage estimates.The rising plate meter (RPM) provides rapid estimates of herbage mass (HM). Accurate calibration of the RPM is difficult due to variability in forage management, growth, and species composition. The RPM is typically calibrated by linear regression of HM and RPM height; however, the r 2 is usually low. Curvilinear regression, with the X intercept set to zero, could provide a more robust calibration equation and decrease variability in RPM estimates. Three Pennsylvania organic dairy farms grazing lactating dairy cattle on multispecies pastures were used to determine measured HM and estimated HM using a RPM. Removal of the X intercept increased the adjusted r 2 of all equations between 42.8 and 89.0%. Use of quadratic and cubic regression only resulted in 0.01 to 0.02 increase in adjusted r 2 . Linear regression remains the simplest and preferred method of calibration; however, error can be reduced by setting calibration equations so that zero RPM height is associated with zero HM.