Conservation agriculture raises crop nitrogen acquisition by amplifying plant-microbe synergy under climate warming.

Abstract

Sustainable crop production in a warming climate requires land management strategies that support plant-soil-microbe interactions to optimize nitrogen (N) availability. Here, we investigate the interacting effects of 10 years' experimental warming and management (conservation vs. conventional agriculture) on wheat N acquisition using in situ ¹⁵N-labeling, root metabolomics and microbial metagenomics. We find that warming amplifies the positive effects on wheat nitrate uptake by 25% in conservation agriculture compared to conventional agriculture, while alleviating microbial competition for N. Additionally, warming increases soil gross N mineralization and nitrification rates by 191% and 159%, but decreases microbial immobilization by 24% in conservation agriculture. Concurrently, microbial genes for mineralization and nitrification are enriched, while those for N immobilization and nitrate reduction are reduced under conservation agriculture with warming. These shifts are driven by alterations in root primary and secondary metabolites, which reshape N-cycling microbial functional niches and optimize multiple microbial N processes beyond mere organic N mining. This reconfiguration increases carbon-nitrogen exchange efficiency, enabling wheat to outcompete soil microorganisms for N. Collectively, our findings suggest that conservation agriculture enhances plant N acquisition by strengthening plant-soil-microbe interactions under climate change, providing a sustainable strategy for future food security.