Interspecific variation and functional classification of root growth among 15 Mongolian grassland species under soil compaction

Abstract

We quantified the interspecific variation in root growth responses to soil compaction across 15 wild Mongolian grassland species and classified their root growth patterns to inform the biological restoration of grassland soils compacted by vehicle traffic. Plants were grown in compacted and uncompacted soil, and we determined root dry mass, diameter, length, specific root length, root depth index and root-to-shoot ratio. Compaction affected root traits in all species differentially, leading to a wide range of trait magnitude in compacted soil. Two primary features effectively explained this interspecific variation: the thick, short root morphology under compaction and the extent to which roots thickened and shortened as an adaptive response. Perennials and monocots generally exhibited thicker and shorter roots in compacted soil compared to annuals and dicots. These findings demonstrate that certain species possess root characteristics making them highly advantageous for the reclamation of compacted soils in Mongolia, and our classification can contribute to selecting those species.