Root Biomass Calculation Using a Modified Counting Technique

Abstract

Data on root weight, length, and surface area are useful in soil characterization, ecosystem description, and studies of plant-soil interaction. Characterization of root systems is often thought to be so laborious and inaccurate that little data are collected. Root counts are used in soil surveys to evaluate root abundance; but these counts are not useful in most applications where data on roots are needed. An improved counting method provided root count data which correlated with measured root weight (AW = 0.97 PW, r2=0.85) where AW = actual weight and PW = predicted weight. Counts were made in a dm2 plexiglass frame parallel to the soil surface under short-and mid-grass prairie vegetation. As many as 30 samples were necessary to estimate root biomass within 25% (P<.10) with either root weighing or counting methods. Total root biomass calculated from root counts in the upper 100 cm of 15 southeastern Montana soils and in mine spoils ranged from 310 to 1,610 g/m2 which is similar to published data on root biomass in other grassland communities.