Long-term evidence for ecological intensification as a pathway to sustainable agriculture

Ecological intensification (EI) could help return agriculture into a ‘safe operating space’ for humanity. Using a novel applicationof meta-analysis to data from 30 long-term experiments from Europe and Africa (comprising 25,565 yield records), weinvestigated how field-scale EI practices interact with each other, and with N fertilizer and tillage, in their effects on long-termcrop yields. Here we confirmed that EI practices (specifically, increasing crop diversity and adding fertility crops and organicmatter) have generally positive effects on the yield of staple crops. However, we show that EI practices have a largely substitutiveinteraction with N fertilizer, so that EI practices substantially increase yield at low N fertilizer doses but have minimal or noeffect on yield at high N fertilizer doses. EI practices had comparable effects across different tillage intensities, and reducingtillage did not strongly affect yields.