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, but 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 method of root separation (inclusion or exclusion of coarse roots) on root foraging precision and its estimation. This allowed us to comment upon 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 root foraging research and their impact on root foraging precision. Root foraging precision is invariable to the studied factors; therefore, it is suitable as a species-specific trait if other factors (such as nutrient patch characteristics) are considered.