Skip to main content
eScholarship
Open Access Publications from the University of California

Crops, Nitrogen, Water: Are Legumes Friend, Foe, or Misunderstood Ally?

  • Author(s): Adams, Mark A
  • Buchmann, Nina
  • Sprent, Janet
  • Buckley, Thomas N
  • Turnbull, Tarryn L
  • et al.
Abstract

Biological nitrogen fixation (BNF) by crop legumes reduces demand for industrial nitrogen fixation (INF). Nonetheless, rates of BNF in agriculture remain low, with strong negative feedback to BNF from reactive soil nitrogen (N) and drought. We show that breeding for yield has resulted in strong relationships between photosynthesis and leaf N in non-leguminous crops, whereas grain legumes show strong relations between leaf N and water use efficiency (WUE). We contrast these understandings with other studies that draw attention to the water costs of grain legume crops, and their potential for polluting the biosphere with N. We propose that breeding grain legumes for reduced stomatal conductance can increase WUE without compromising production or BNF. Legume crops remain a better bet than relying on INF.

Many UC-authored scholarly publications are freely available on this site because of the UC's open access policies. Let us know how this access is important for you.

Main Content
Current View