rising plate meter

Bijeenkomst: EGF2015
Auteur: Holshof G., Stienezen M.W.J. and Galama P.G.
ISBN: 978-9090-289-61-8
Jaar van uitgifte: 2015
Producttype: Paper
To obtain good grassland management, especially under grazing, requires accurate information about grass growth. In the Netherlands several methods have been introduced to estimate herbage mass. At present the rising plate meter is the most accessible tool for Dutch farmers; it is cheap and easy to use. However, the equations for translation of grass height, as measured with the rising plate meters, into measures of herbage mass, have been developed in the countries of origin of the meters. To check the equations for the situation in the Netherlands in 2014 five rising plate meters were calibrated. Grass height was estimated with the five rising plate meters on small plots on which the grass was then cut and dried to measure the dry matter (DM) yield. For each rising plate meter a calibration curve was estimated. DM yield was estimated from ground level and from 5 cm stubble. Information about the herbage mass in the stubble was also estimated by cutting the stubble to ground level. The results show that for three rising plate meters the same equation can be used. Two rising plate meters need a different equation. The rising plate meters are relatively reliable for a measured grass sward of 20-25 cm in height from ground level. This means that a good estimate of DM yield can be made for up to 2,500 kg DM ha‑1 above 5-cm stubble height.

Bijeenkomst: EGF2015
Auteur: McSweeney D., Foley C., Halton P. and O’Brien B.
ISBN: 978-9090-289-61-8
Jaar van uitgifte: 2015
Producttype: Paper
Irish and European pasture-based systems of farming rely upon precise grass measurement and allocation to (1) achieve optimal economic return, as grazed grass is the cheapest feed source, and (2) to maintain the regrowth of high quality grass in each subsequent grazing. On farms implementing an intensive grazing system, grass management is usually carried out by subjective visual measurement and intuitive decision-making. To add objectivity to this process an automated grass measurement tool has been developed which will increase the precision of grass measurement and allocation for pasture-based systems of farming. The aim of this study was to calibrate this tool, to provide a decision support tool (DST) for farmers capable of precise grass height measurement with global positioning system location information. The operation of the DST involves the use of a micro-sonic sensor that finds the distance from a module, placed on the shaft of a rising plate meter, to the plate, by recording the time difference between the transmission and its reflective return from the plate. The results of this study indicate that the absolute height measurement of the DST is similar to that of a ‘gold-standard’ rising plate meter.

Bijeenkomst: EGF2015
Auteur: Schori F.
ISBN: 978-9090-289-61-8
Jaar van uitgifte: 2015
Producttype: Paper
Pasture-based production systems are economically interesting, but only if grown herbage is efficiently used. The sward surface height (SSH) and the herbage mass (HM) are appropriate indicators to use in checking pasture management and thereby improving the output of milk and meat per hectare (ha). Because farms are becoming larger, the periodic measurement of SSH with a rising plate meter takes more and more time. Devices towed by small vehicles, such as the C-DAX Pasturemeter (PM), could reduce the workload significantly if the measurements are carried out correctly. To verify the estimation accuracy of the PM as compared to an electronic rising plate meter, the SSH of 252 strips (each approximately 8 m2) and 187 paddock diagonals on multi-species pastures of two farms were measured. Subsequently, the strips were cut, and the harvested biomass was weighed. The dry matter (DM) of a subsample of the biomass was determined to calculate the HM in kg DM ha‑1 over 49 mm. Because the measuring principles of the two devices are different, equations were created for the conversion of SSH. Furthermore, regressions were developed to estimate the HM based on the SSH. With the two devices, HM estimations of similar quality were obtained.