Development and evaluation of a root washing machine towards efficient and standardized sampling of roots

Abstract

To improve the efficiency and standardization of root washing for root evaluation, we developed a root washing machine and evaluated its ability to separate roots from soil aggregates. This machine was constructed from commercially available materials including polyvinyl chloride pipes, and it separates soil from roots using a jet of water from a spray nozzle. In tests using soil aggregates containing rice roots obtained by the core sampling method, the average processing time per sample was approximately 5.5 minutes, and this time was unchanged even when the sample volume was doubled. Root lengths were measured separately for those from the upper part and for those remaining in the bottom part of the machine. The roots from the upper part accounted for 90% of the total root length. The root length density was high compared with values reported in a previous study. These results suggest that the proposed root washing machine is a labor-saving and highly reproducible device for root washing; further testing with other crop species and soil conditions is needed.