Higher yields in formerly drought-stressed Lolium perenne and Cichorium intybus due to increased carbohydrate reserves, higher root biomass, and increased mineral soil N.
In: Sustainable meat and milk production from grasslands, Volume 23. June, Publ. European Grassland Federation, Wageningen Academic Publishers. 2018, 357-359.
We investigated yield resilience from drought stress in monocultures of Lolium perenne L. and Cichorium intybus L. in a field experiment in northern Switzerland. A summer drought was induced with complete rain exclusion for nine weeks. Drought effects were compared to rainfed control conditions at the end of the drought period and six weeks later after a post-drought period with adequate water supply. To explain yield responses, we measured plant-available N in the soil, water soluble carbohydrates in plant storage organs (stubbles), and root biomass of species. During the last five weeks of the drought period, L. perenne and C. intybus revealed an average change in aboveground biomass (compared to the rainfed control) of - 68% (P < 0.001). During the six-week post-drought period, formerly drought-stressed species were highly resilient and significantly outperformed the yield level of the rainfed control by + 62% (P < 0.05). This yield advantage could be explained by significantly increased concentrations of water soluble carbohydrates in storage organs (+ 64%) and higher root biomass (+ 66%) of formerly droughtstressed species, and a four-fold increase in plant-available soil N during the post-drought period. As a result, aggregated over the drought and post-drought periods, surprisingly no negative drought impact on yield was observed.