Ecological intensification (EI) could help return agriculture into a ‘safe operating space’ for humanity. Using a novel application of meta-analysis to data from 30 long-term experiments from Europe and Africa (comprising 25,565 yield records), we investigated how field-scale EI practices interact with each other, and with N fertilizer and tillage, in their effects on long-term crop yields. Here we confirmed that EI practices (specifically, increasing crop diversity and adding fertility crops and organic matter) have generally positive effects on the yield of staple crops. However, we show that EI practices have a largely substitutive interaction with N fertilizer, so that EI practices substantially increase yield at low N fertilizer doses but have minimal or no effect on yield at high N fertilizer doses. EI practices had comparable effects across different tillage intensities, and reducing tillage did not strongly affect yields.
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The datasets analysed during the current study are available from the authors on reasonable request. Please contact the corresponding author for assistance. Data from LTEs belonging to Rothamsted Research are available on reasonable request via the e-RA platform (www.era.rothamsted.ac.uk). We have refrained from depositing data into a public repository due to the need for guidance to correctly interpret LTE designs and datasets and the need to ensure that the substantial investments by each institute in maintaining LTEs do not go unacknowledged when data are used.
R scripts used in the analyses are also available from the corresponding author on reasonable request.
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The authors thank everyone who has been involved in designing, maintaining, funding, and collecting and managing data from all LTEs included in this study. We are grateful to the GLTEN (https://glten.org/), funded by the Thirty Percy Foundation for providing meta-data on the LTEs. The Rothamsted Long-term Experiments National Capability (LTE-NC) is supported by the UK BBSRC (BBS/E/C/000J0300) and the Lawes Agricultural Trust. LTEs belonging to SRUC are supported through Scottish Government RESAS Strategic Research Programme. C.M., J. Storkey, A.M. and L.C. were supported by the ‘GLTEN-Africa’ project (BB/R020663/1) funded by the Global Challenge Research Fund programme of the Biotechnology and Biological Sciences Research Council (BBSRC), and J. Six and A.M. also by the BBSRC Soils to Nutrition project (BBS/E/C/000I0320). For the purpose of open access, the authors have applied a Creative Commons Attribution (CC BY) licence to any Author Accepted Manuscript version arising.
The authors declare no competing interests.
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MacLaren, C., Mead, A., van Balen, D. et al. Long-term evidence for ecological intensification as a pathway to sustainable agriculture. Nat Sustain (2022). https://doi.org/10.1038/s41893-022-00911-x