Plant–microbial linkages and ecosystem nitrogen retention: lessons for sustainable agriculture

The use of nitrogen (N) in fertilizer has doubled the amount of reactive N in the biosphere, leading to increased greenhouse‐gas emissions and nutrient enrichment in aquatic and terrestrial ecosystems. Despite the global impact of N, many uncertainties exist about the factors that determine the loss and retention of fertilizer‐associated N in terrestrial ecosystems. A growing body of evidence shows that linkages between plants and soil microbes play a major role in controlling the loss and retention of N. The promotion of such plant–microbial linkages in agricultural systems has the potential to enhance N retention and reduce N loss. Although trade‐offs with agricultural yield are inevitable, promoting plant–microbial linkages will reap benefits in terms of plant crop resistance to climate change as well as to pests and diseases.