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

Abstract

Grassland fires are the most common disturbance in Mongolia's east. Fire risk management in Mongolia's eastern grasslands should include fuel load estimates (aboveground plant biomass) to prevent fire damage. The disc pasture meter (DPM) is a common, rapid, and nondestructive method for estimating aboveground plant biomass in grasslands. Calibration is needed for the DPM application in a given area due to regional variations in climate and plant diversity, as well as site-specific environmental factors. We calibrated a DPM for Mongolia's north-eastern grasslands bordering Russia, classified as a very high-risk region for grassland fire. The calibration was carried out at twelve different sites, and double sampling (DPM reading and plant biomass harvesting) was done at 108 points. The mean of the total dry plant biomass of the sites was 11.27 centner ha-1 (±1.93 SE). The sites differed in total dry plant biomass and its composition. It indicates that the sites are needed different fire managements. Although we developed three linear regression models for DPM readings (100, 200, and 300) to estimate an optimal sampling effort, the model with 300 DPM models had the highest determination coefficient (0.82). Therefore, we suggest the model (y=3.18x+3.1) with the 300 DPM readings for further application.