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Drought is the most significant environmental stress in agriculture worldwide because of its adverse impact on agricultural productivity and sustainability, and, thus, resilient farming practices need to be developed to ensure food security. The main objective of this project is to compare the response to simulated summer drought of the main Swiss arable farming systems.

As a result of global climate change, some of the most severe weather events, including drought events, will become more frequent in Europe over the next 50 to 100 years. Thus, farming practices have to be developed that ensure food security, but so far, it is unclear which farming systems are most resilient against climate change. Here, we will compare the main Swiss arable farming systems (organic arable farming with tillage, organic arable farming with reduced tillage, conventional arable farming with tillage and conventional arable farming without tillage) and test their response to simulated summer drought.

Our over-arching hypotheses are that (1) organic farming is more resilient to summer drought than conventional farming because crop yields and thus water use are lower and because plant symbionts, known to provide drought and stress resilience, are more abundant in organic farming systems; (2) reduced tillage or no tillage are more resilient to summer drought than tillage because reduced tillage stabilizes soil structure and improves water availability to crops which in turn ensures plant productivity; and (3) despite lower yields, economic profits per hectare, are equal or even higher under drought conditions for organic than for conventional farming because prices are higher for organic products and yield reductions are expected to be larger for conventional than for organic farming. We will test these hypotheses using the FAST trial (Farming Systems and Tillage Experiment), a replicated field trial established in 2009. We will simulate summer drought with portable roofs, and will investigate the effects of simulated drought on plant yield, nutrient uptake and grain quality in four Swiss production systems (WP1), identify the potential mechanisms being responsible for enhanced resilience of these farming systems to summer drought (WP2, WP3) and put the results into a socio-economic perspective (WP4).