Cultivation legacies alter soil nutrients and differentially affect plant species performance nearly a century after abandonment

Cultivation legacies affect native vegetation in old fields of the Great Basin, USA for nearly a century after these fields are abandoned. We hypothesized that cultivation lowered soil nutrients and that this legacy would differentially impact plant performance of four representative Great Basin species. To test these hypotheses, we compared soil nutrients (C, N, P, K, Mg and Ca) between two formerly cultivated and adjacent noncultivated sites in two soil series. We then compared the plant growth and foliar nutrient content of an exotic grass (Bromus tectorum L.), two native grasses (Elymus elymoides Raf.] Swezey and Achnatherum hymenoides Roem. and Schult.] Barkworth), and a native forb (Sphaeralcea grossulariifolia Hook. and Arn.] Rydb) grown in these soils in the greenhouse and in the field. Only one sampling site had reduced soil nutrients associated with cultivation legacies, where most of the negative effects on plant performance were found. E. elymoides appeared to be less affected by cultivation legacies than did A. hymenoides, which had a reduced survivorship and 20 % less above-ground biomass in cultivated soils. No species, including B. tectorum, were favored by cultivation. Our findings suggest that cultivation legacies can affect plant performance of different species in different ways and that altered soil nutrients may interact with other abiotic and biotic cultivation legacies in complex ways.