Grassland species show similar strategies for sulphur and nitrogen acquisition

BACKGROUNDS AND AIMS: Plant nutrition strategies play a crucial role in community structure and ecosystem functioning. However, these strategies have been established only for nitrogen (N) acquisition, and it is not known whether similar strategies hold for other macronutrients such as sulphur (S). The aim of our study was to determine whether strategies for S acquisition of some grassland species were similar to those observed for N acquisition, and to analyse the relationships between these plant strategies and the soil microbial activity involved in soil organic S mineralisation. METHODS: We used three exploitative and three conservative grass species grown with and without S fertilisation. We measured a set of plant traits, namely root and shoot biomass, leaf area, root length, N and S content, leaf nutrient use efficiency, and sulphate uptake rates in plants, and one microbial trait linked to S mineralisation, namely soil arylsulphatase activity. RESULTS: The set of plant traits differentiated exploitative from conservative species. Close relationships were found between traits associated with strategies for N acquisition, namely total N content and Leaf N Use Efficiency (LNUE), and traits associated with strategies for S acquisition, namely total S content and Leaf S Use Efficiency (LSUE). Exploitative species exhibited similar or lower sulphate uptake capacities per unit of biomass than conservative species, but acquired more S through their larger root systems. Greater arylsulphatase activity was observed in the rhizosphere of the most exploitative species. CONCLUSION: Overall, our results show that nutrient strategies defined in grassland species for N acquisition can be extended to S.