Disc pasture meter calibration to estimate grass biomass production in the arid dunefield of the south-western Kalahari

Calibration of disk pasture meter to estimate a fire fuel load (aboveground plant biomass) for fire management in the northeastern steppe of Mongolia

“…Previous published models were developed mainly in African savannas; they are linear regressions explaining more than 80% of the aboveground plant biomass. The models are diff erent for their coeffi cients because of heterogeneity in plant composition and productivity in savannas (Harmse et al, 2019). For example, the model developed in short grass savannas yielded negative values of aboveground plant biomass for low DPM readings (Trollope & Potgieter, 1986).…”

“…A common nondestructive instrument is the disc pasture meter (DPM) (Bransby & Tainton, 1977). The disc pasture meter was used in many grasslands of the world (Bransby & Tainton, 1977;Brockett, 1996;Trollope, 1983;Trollope & Potgieter, 1986;Zambatis et al, 2006;Dörgeloh, 2002;Harmse et al, 2019), and proved to be a technique providing accurate measurements for land managers and technicians, who desire a rapid precise assessment of standing biomass estimation covering large scale area and time. Although previous studies provided signifi cant linear regression models between DPM readings and plant standing biomass, the DPM application requires calibration for a given region, because parameters of regression models vary due to not only regional diff erences in climate and plant diversity but also local variation in plant communities and site-specifi c environmental factors (Dörgeloh, 2002;Zambatis et al, 2006;Dougherty et al, 2013).…”

CALIBRATION OF THE RISING PLATE METER FOR MIXED PASTURES OF RYEGRASS (Lolium perenne L.) AND KIKUYO (Cenchrus clandestinus)

“…The simple linear regression is a model that fit to predict the AHM in CH function. In fact, this is the most commonly used model for RPM calibration tests in different forage species (Michell, 1982;Michell and Large, 1983;Van der Colf, et al, 2013;Nakagami, 2016;Harmse et al, 2019;Cho, et al, 2019;Rayburn, 2020). Dillard et al (2016) evaluated the performance of the RPM in multispecies pastures composed of grasses, legumes and weeds, and reported that even, when equating the intercept to 0, the best prediction equation is a linear regression.…”

“…This shows that the rate of change for each height centimeter of the RPM measures is lower for mixed meadows composed of L. perenne and C. clandestinum, which can be explained by the fact that the RPM calibration is being carried out for grasses with different growth habits (Gastal and Lemaire, 2015;Escobar et al, 2020). Some studies that calibrated the RPM calling it Disc Pasture Meter (DPM) in highly fibrous grasslands such as Stipagrostis amabilis found that the slope for this type of species is approximately twice than the used for L. perenne and mixed grasslands (Harmse, et al, 2019). On the other hand, Nakagami, (2016) reported slopes that vary between 10 and 20 kg DM ha -1 depending on the species sampled.…”