Methods for Estimating Pasture Dry Matter on Dairy Farms in Northland

Herbage mass and rising plate meter (RPM) height was estimated using the RPM as part of a farmlet trial, at No. 2 Dairy, Dexcel Hamilton. Herbage mass estimations were collected over a 3-year period, from pre- and post-grazing and weekly farm walk estimates. The aim of the study was to determine how appropriate the RPM was for use on New Zealand dairy farms. The RPM gives reliable information using 50 readings per paddock for paddock selection, grazing residual, and average herbage mass between 1000 and 4000 kg DM/ha. There was a tendency however, for the RPM to underestimate herbage mass when compared with visual estimates. The RPM is limited in its estimation of herbage mass above 4000 kg DM/ha and cannot be relied upon to give useful results for dry matter intake and net herbage accumulation (particularly with weekly farm walk data). As long as RPM limits are observed, overall results show that the RPM is an inexpensive tool to aid in farm monitoring and decision making. Keywords: dairy farming, grazing residual, herbage mass, rising plate meter, RPM height

Section: Rpm Herbage Mass (Kg Dm/ha)supporting

confidence: 63%

Practical use of the rising plate meter (RPM) on New Zealand dairy farms

Lile¹,

Blackwell²,

Na³

et al. 2001

“…This study shows that the RPM and more particularly the pasture probe reliably and accurately estimate herbage mass of ryegrass/white clover dairy pastures at Ruakura and Taranaki. Piggot (1986) concluded they were also accurate in Northland. Commercially available pasture probes have the additional advantage that conversion of meter readings to kg DMlha is automatic.…”

Section: Discussionmentioning

confidence: 99%

Estimation of Herbage Mass in Ryegrass/White Clover Dairy Pastures

L'Huillier¹,

Na²

1988

The pasture probe, rising plate meter (RPM), ward height and visual assessment methods were compared for the estimation of the herbage mass of dairy pastures. The pasture probe and calibrated visual assessment were slightly more accurate than others. Visual assessment without calibration was less accurate than all other methods. There was little difference between operators of the pasture probe and RPM, but operator variation was large with visual assessment. Variation between calibrations from different days, seasons, and sites was large. Only dead material content was identified to influence this variation. Pooling of calibrations, double sampling procedures, and derivation of different calibration slopes for each day from an equation fitted to calibration data are procedures discussed for the estimation of herbage mass by farmers, advisors and researchers. Wide adoption of methods such as the pasture probe or RPM with "universal" calibrations could reduce inconsistent advice offered to farmers, and can be used with confidence. Keywords: capacitance probe, rising plate meter, visual assessment, ward height, grassland management, pasture composition, pasture assessment.

“…Pasture height measurement has previously been shown to be no more precise than other indirect pasture estimation technologies, such as the plate and probe, on Northland dairy pastures (Piggot 1986). Some of the inherent disadvantages of using sward height to estimate pasture mass also apply to the pasturemeter.…”

Section: Discussionmentioning

confidence: 99%

Calibration of the C-DAX Rapid Pasturemeter and the rising plate meter for kikuyu-based Northland dairy pastures

Rennie¹,

King²,

Puha³

et al. 2009

Accurate estimation of pasture mass is essential for managing farm systems for top performance. The C-DAX Rapid Pasturemeter has the potential to provide fast, accurate estimates of pasture mass. However, the Pasturemeter has been calibrated for 'typical' temperate dairy pastures and its suitability for use on kikuyu (Pennisetum clandestinium)-based pastures in Northland, is unknown. This study determined the accuracy of the technology for estimation of pasture mass on kikuyu/ryegrass-based dairy pasture on the Northland Agricultural Research Farm at Dargaville, New Zealand. Keywords: pasture mass estimation, kikuyu, Northland, dairy, calibration