Crop rotations sustain cereal yields under a changing climate

Abstract

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.

The influence of rainfall and tillage on wheat yield parameters and weed population in monoculture versus rotation systems

“…Wheat-based monoculture is common in the Mediterranean region 32 and the growth cycle of winter wheat, which is the most important rainfed crop in our area, is affected by drought. It is known that a well-planned crop rotation (with the adoption of legume and/or cruciferous crops within the cereal rotation scheme) can increase the sustainability of the system in dry regions of the Mediterranean basin 33 – 35 . From national to regional spatial scales, growing a greater diversity of crops increases the stability of the regional harvest of all crops combined, acting as a buffer to climate variability 36 .…”

Large-scale deployment of grass in crop rotations as a multifunctional climate mitigation strategy

“…Understanding overall rotation effects on yields requires, as for SOC sequestration rates, data from long-term agricultural field experiments. Based on data from seven such experiments across Europe, Marini et al 43 show that diversified crop rotations (e.g., including temporary leys) provided higher yields for both winter and spring cereals (average +0.86 and +0.39 t ha -1 yr -1 , respectively), compared with a continuous monoculture of cereals. Yield gains were higher in years with high temperatures and limited precipitation, i.e., conditions expected to become more frequent in the future climate, up to around 1 t ha -1 yr -1 compared to monocultures 43 .…”

“…Based on data from seven such experiments across Europe, Marini et al 43 show that diversified crop rotations (e.g., including temporary leys) provided higher yields for both winter and spring cereals (average +0.86 and +0.39 t ha -1 yr -1 , respectively), compared with a continuous monoculture of cereals. Yield gains were higher in years with high temperatures and limited precipitation, i.e., conditions expected to become more frequent in the future climate, up to around 1 t ha -1 yr -1 compared to monocultures 43 . Angus et al 42 estimate that on a global level, 40% of the wheat area is not preceded by an effective break crop, forage, or fallow, indicating a substantial potential for yield increases.…”

Methods of yield stability analysis in long-term field experiments. A review

“…For farmers, temporal yield stability is relevant because it determines economic predictability and reduces risk. Yield stability is especially important related to grain legume cultivation, as these crops are perceived to be less stable than others (Watson et al 2017;Reckling et al 2020) and in the context of cropping system diversification that is often assumed to increase yield stability (Reckling et al 2019;St-Martin et al 2017;Marini et al 2020). Stability is also highly relevant for plant breeders developing genotypes adapted to a wide range of environmental conditions (Mühleisen et al 2014).…”

“…While stability analysis was originally used to assess the stability of crop genotypes across environments (Becker and Léon 1988), the analysis of yield stability has been widened to various systems, comparing (i) crop production systems, e.g. organic and conventional (Knapp and van der Heijden 2018); (ii) cropping systems (Macholdt et al 2020b;St-Martin et al 2017;Marini et al 2020); and (iii) crop species (Reckling et al 2018b) and mixtures (Raseduzzaman and Jensen 2017) and (iv) to assess changes of yield stability over time (Reckling et al 2018a;Döring and Reckling 2018;Singh and Byerlee 1990;Schauberger et al 2018;Macholdt et al 2021). Yield stability has especially gained importance in research on impacts of climate change (Tigchelaar et al 2018;Lobell et al 2011;Webber et al 2020).…”