Increased mineral soil N availability contributes to post-drought yield outperformance of Lolium perenne
Schärer M.L., A. Lüscher and and A. Kahmen . 2022.
Abstract
Reoccurring drought events severely restrict forage production. However, intensively managed grasslands
have recently been reported to recover quickly after drought stress and to even outperform control yields.
Despite several studies showing increased mineral N availability after drought, the contributions of the
two N sources: (1) fertilizer-derived N accumulated during drought; and (2) increased availability of
soil-derived mineral N, remain unclear. Thus, we examined the effect of a 2-month experimental summer
drought and two fertilization levels during drought (non-fertilized and fertilized) on the recovery of
Lolium perenne swards after rewetting. Even for non-fertilized swards, dry matter yield (DMY) and
plant-available N of drought and rewetted (DRW) plots exceeded controls. Fertilization during drought
increased the effects of DRW on DMY and on plant available N. Consequently, our study shows that
formerly drought stressed swards surpass control yields by profiting from higher N availability, not only
deriving N from accumulated fertilizer N but also from increased availability of soil-derived N due to
changed soil processes.
Key Words
grassland, drought, yield outperformance, ryegrass, N availability, resilience
