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Fifty-years time series of Sun Spot Number, Western Mediterranean Oscillation Index, Italiangrain productions of Wheat and Maize, and those from a Long Term Agronomic Experimentheld in Bologna, have been compared to identify trends and fluctuations. Data, denoisedby EMD and SSA, are analysed by wavelet technique, showing how SSN oscillations affectregional scale dynamics, where in the last two decades a range of fluctuations (7–16 years)is also evident. Both signals also reflects on yield fluctuations of Wheat and Maize at bothnational and local level, as is evidenced by cross-wavelet analysis. Results are useful forproduction forecasts and risk analysis.

Soils store vast amounts of carbon (C) on land, and increasing soil organic carbon (SOC) stocks in already managed soils such as croplands may be one way to remove C from the atmosphere, thereby limiting subsequent warming. The main objective of this study was to estimate the amount of additional C input needed to annually increase SOC stocks by 4‰ at 16 long-term agricultural experiments in Europe, including exogenous organic matter (EOM) additions. We used an ensemble of six SOC models and ran them under two configurations: (1) with default parametrization and (2) with parameters calibrated site-by-site to fit the evolution of SOC stocks in the control treatments (without EOM). We compared model simulations and analysed the factors generating variability across models. The calibrated ensemble was able to reproduce the SOC stock evolution in the unfertilised control treatments. We found that, on average, the experimental sites needed an additional 1.5 ± 1.2 Mg C ha−1 year−1 to increase SOC stocks by 4‰ per year over 30 years, compared to the C input in the control treatments (multi-model median ± median standard deviation across sites). That is, a 119% increase compared to the control. While mean annual temperature, initial SOC stocks and initial C input had a significant effect on the variability of the predicted C input in the default configuration (i.e., the relative standard deviation of the predicted C input from the mean), only water-related variables (i.e., mean annual precipitation and potential evapotranspiration) explained the divergence between models when calibrated. Our work highlights the challenge of increasing SOC stocks in agriculture and accentuates the need to increasingly lean on multi-model ensembles when predicting SOC stock trends and related processes. To increase the reliability of SOC models under future climate change, we suggest model developers to better constrain the effect of water-related variables on SOC decomposition. This work benefited from the French state aid managed by the ANR under the “Investissements d'avenir” programme with the reference ANR-16-CONV-0003 (CLAND project). EB, RZA and BG are supported by the European Union's Horizon 2020 research and innovation program under grant agreement No 101000289 (Holisoils project). RZA was also supported by the United States Department of Energy, Office of Science, and Office of Biological and Environmental Research. Oak Ridge National Laboratory is managed by UT-Battelle, LLC, for the United States Department of Energy under contract DE-AC05-00OR22725.

Agriculture is facing the complex challenge of satisfying increasing food demands, despite the current and projected negative impacts of climate change on yields. Increasing crop diversity at a national scale has been suggested as an adaptive measure to better cope with negative climate impacts such as increasing temperatures and drought, but there is little evidence to support this hypothesis at the field scale. Using seven long-term experiments across a wide latitudinal gradient in Europe, we showed that growing multiple crop species in a rotation always provided higher yields for both winter and spring cereals (average +860 and +390 kg ha−1 per year, respectively) compared with a continuous monoculture. In particular, yield gains in diverse rotations were higher in years with high temperatures and scant precipitations, i.e. conditions expected to become more frequent in the future, rendering up to c. 1000 kg ha−1 per year compared to monocultures. Winter cereals yielded more in diverse rotations immediately after initiation of the experiment and kept this advantage constant over time. For spring cereals, the yield gain increased over time since diversification adoption, arriving to a yearly surplus of c. 500 kg ha−1 after 50–60 years with still no sign of plateauing. Diversified rotations emerge as a promising way to adapt temperate cropping systems and contribute to food security under a changing climate. However, novel policies need to be implemented and investments made to give means and opportunities for farmers to adopt diversified crop rotations.

International audience; Arable land is a major component both in landscape and in the food production system. The ability to understand and describe how spatial and dynamical characters affect human life and eventually to design the agricultural systems beyond the processes ruling them is fundamental to preserve land and ensure economic, ecological and social sustainability. In this paper, we will refer to cropping scheme as a general term merging two aspects of cropping systems, the spatial and the temporal one, represented respectively in terms of crop pattern and crop rotation. Analysis of crop rotations is of basic importance in sustainable farming strategies dealing with climate change, food security and organic farming. In fact, crop rotations are fundamental to maintaining fertility and, even if their analysis often focus on local crops, they help face market and weather uncertainties as well as interpret landscape diversity and its dynamics (Dury et al., 2012, Thenail et al. 2009). In European Community (EC) an agricultural holding database standard has been developed, the Farm Accountancy Data Network (FADN), which is seldom rich in information on farm management techniques. The present study makes use of Italian FADN to identify more recurrent crop patterns and evaluate the possibility to describe them as a crop rotation [...]