Herbaceous biomass can be estimated by destructive sampling or indirect methods. Destructive sampling involves harvesting aboveground biomass from a quadrate of known size, and then oven drying and recording dried weight. This is direct and accurate method however, care has to be taken while selecting quadrate size and number of quadrates per site to capture heterogeneity within the target canopy.
Indirect methods for herbaceous biomass are as follows:
- Rising Plate Meter: It is used to measure canopy height that is then converted into biomass using simple allometric equation. Details can be found here.
- Wellington boots for pasture walking: Similar to Rising Plate Meter these wellies are used to measure canopy height which can later be associated with rough estimate of biomass. Details can be found here.
- Biomass estimation from digital photographs: This is rather unconventional method and still in the research phase. Photographs of the biomass are compared against calibration images. The sequence of calibrated image is developed by comparing the images against destructively measured biomass data. The key factors in this method are acquiring photographs with same orientation as the calibration images. If performed carefully the method can yield reliable results.
Reference:
Morgan, H. R., Reid, N. & Hunter, J. T. Estimation of aboveground herbaceous biomass using visually ranked digital photographs. Rangel. J. 40, 9–18 (2018).