Paper chromatography: An inconsistent tool for assessing soil health

Although paper chromatography is being promoted as a cost-effective tool for rapid assessment of soil health, few studies have explored the quantitative relationship between chromatogram features and soil health variables, and no studies have investigated the association between chromatogram features and microbial diversity as determined using DNA sequences. We assessed 343 soil samples from varying land uses in southwestern Australia to investigate the relationship between total organic carbon, microbial activity and diversity, salinity and pH levels and 12 chromatogram features. Spearman's correlations and variance partitioning were used to detect relationships. Although total organic carbon and microbial activity displayed the strongest correlations with chromatogram features, they were not associated with greater development of radial features and median zone radius as expected. This was in contrast to what has been previously reported, implying context dependent responses of chromatogram features to gradients in soil variables. Microbial community structure was found to explain changes in chromatogram features better than the measured soil variables. These results indicate that further studies are necessary before paper chromatography is embraced as a tool for soil health assessment, and raises questions regarding the use of chromatography by community groups as a tool to measure soil health.