Evaluation of weighted disc meter for pasture yield estimation on intensively stocked dairy pasture

Abstract

The accuracy of a weighted disc meter for measuring yields of pasture dry matter (DM) was determined on paddocks intensively grazed by dairy cows. Separate regression relationships between DM yields and discreadings were calculated during early summer, late summer, autumn, and winter from December 1972 to July 1973. Best relationships were obtained in winter and worst in late summer and autumn. Significant differences in regressions between seasons appeared to be due to changes in both percentage DM and proportions of the individual species in the swards.Alternative methods for obtaining acceptably accurate estimates of the mean meter reading for individual paddocks, and the effects of level and uneven ground on regressions of pasture DMon meter readings, were examined.The accuracy of the meter for predicting total pasture DM was acceptable during winter but not during summer and autumn.The meterwas easy to use. During winter, readings taken at 5 sites were assessed subjectively as representative of equal proportions of each paddock, and gave mean values closely related to others derived from 60 measurementsmade systematically over the same total areas.Practical applications of the meter are discussed and the results are compared with others published previously. © 1974 Francis Group, LLC.