Study on the foraging behavior of clonal roots and its influencing factors in Populus euphratica Oliv.

We investigated differences in foraging behavior of the proximal and distal roots of Populus euphratica Oliv. in a heterogeneous natural forest habitat and estimated the key influencing factors of foraging behavior traits, including main root depth (MRD), root diameter (RD), main root length (MRL), fine root biomass (FRB), and root sucker density (RSD). In total, five sample plots were established in Ejin Oasis, Inner Mongolia, and Northern China. A total of 25 clonal root branches were manually excavated and corresponding belowground environmental factors were analyzed. Results showed that the MRL, RD, and MRL values were significantly higher for proximal roots than for distal roots, whereas the FRB and RSD values were significantly lower. Soil total phosphorus had a major positive influence on the MRL of clonal roots. The RD values of proximal roots increased with soil total carbon, and RSD values were positively controlled by soil water content and biomass of neighbor root. Soil compaction and biomass of neighbor root had negative effects on the MRD of distal roots. Soil water content, soil total nitrogen, biomass of neighbor root, and soil compaction had positive effects on the FRB of distal roots. Thus, our results indicate that clonal roots improve C-storage ability and locate better environments by increasing the MRL and RD of proximal roots and improve nutrient acquisition and ramet production by increasing the FRB and RSD of distal roots.