Effect of wet and dry cycles in calcareous soil on mineral nutrient uptake of two grasses,Agrostis stolonifera L. and Festuca ovina L.

Shoot uptake of mineral nutrients (Ca, Cu, Fe, K, mg, Mn, P, S, Zn) by Agrostis stolonifera L. was compared with Festuca ovina L. under wet and dry cycles. Such conditions are typical for A. stolonifera sites, whereas F. ovina is growing mostly on consistently drier and better-drained soils. Plants were grown in a glasshouse, at controlled temperature and light conditions, using two moisture regimes, one constant at 60% WHC (water holding capacity), one wet/dry fluctuating between 35 and 100% WHC. Above ground and total biomass production was lower under wet/dry treatment than at constant water regime in F. ovina, but did not differ between regimes in A. stolonifera. Shoot uptake of most elements was severely reduced in F. ovina at the wet/dry regime. Shoot uptake and concentrations of most elements studied (Cu, K, Mn, P, S, Zn) were lower (p<0.05) under wet/dry treatment than at constant regime in A. stolonifera and tended to be lower also of Fe and Mg. Differences in biomass production observed are consistent with field evidence that A. stolonifera grows in sites which are periodically flooded but may become quite dry during other periods, and that F. ovina is limited to sites which are consistently drier and better drained. Evidence from the present study, however, does not support any view that alternating wet and dry cycles, as typical of A. stolonifera field sites, would be beneficial to nutrient acquisition of this species but that biomass production may develop normally at the lower uptake of most mineral nutrients measured under the wet/dry regime. Such regimes are decidedly unfavourable to both growth and nutrient acquisition of F. ovina.