Soil types will alter the response of arable agroecosystems to future rainfall patterns

Climate change scenarios for central Europe predict fewer but heavier rains during the vegetation period without substantial changes in the total amount of annual rainfall. To investigate the impact of rainfall patterns derived from regionalised IPCC scenarios on agroecosystems in Austria, we conducted an experiment using 3 m2 lysimeters where prognosticated (progn.) rainfall patterns were compared with long-term current rainfall patterns on three agriculturally important soil types (sandy calcaric phaeozem, gleyic phaeozem and calcic chernozem). Lysimeters were cultivated with field peas (Pisum sativum) according to good farming practice. Prognosticated rainfall patterns decreased crop cover, net primary production (NPP) and crop yields, but increased root production and tended to decrease mycorrhization. Soil types affected the NPP, crop density and yields, weed biomass and composition, as well as the root production with lowest values commonly found in sandy soils, while other soil types showed almost similar effects. Significant interactions between rainfall patterns and soil types were observed for the harvest index (ratio crop yield versus straw), yield per crop plant, weed density and weed community composition. Abundance of the insect pest pea moth (Cydia nigricana) tended to be higher under progn. rainfall, but was unaffected by soil types. These results show that (a) future rainfall patterns will substantially affect various agroecosystem processes and crop production in the studied region, and (b) the influence of different soil types in altering ecosystem responses to climate change should be considered when attempting to scale-up experimental results derived at the plot level to the landscape level.