Root Foraging Precision: Do Experimental Conditions Matter?

Abstract Purpose: Root foraging precision, i.e., preferential root proliferation in nutrient-rich patches in heterogeneous soil, contributes significantly to plant nutrient acquisition. The ability to forage is usually studied experimentally, although often under different conditions. It remains unclear whether different experimental conditions affect root foraging precision. We studied the effect of experiment duration, pot size and root separation on root foraging precision and the appropriateness of using root foraging as species-specific values in databases and meta-analyses.Methods: We cultivated three perennial species in pots with spatially heterogeneous nutrient supplies and manipulated the experiment duration (4 – 10 weeks). We partly replicated the experiment in two consecutive years. In two of the three species we compared outcomes when root types were separated and unseparated, and for one species we also manipulated pot size. We assessed the effects of the manipulated factors on foraging precision expressed as the ratio of root biomass in nutrient-rich and poor patches.Results: Root foraging precision was not affected by experiment duration or pot size. Separating roots to use only the fine ones for root foraging assessment amplified foraging precision values and reduced their intraspecific variation.Conclusions: Our study investigated various methods of the root foraging research and their impact on the root foraging precision. Root foraging precision is invariable to the studied factors, therefore it is suitable as a species-specific trait, if the effect of other factors (such as nutrient patch characteristics) is taken into account.