Research Questions

Stakeholders generated a large number of questions about nitrogen in California agriculture. We took the entire list of stakeholder questions and synthesized them into overarching research questions relating to nitrogen biogeochemistry, on-farm practices, policy, health, and communications. We aim to answer these questions in the assessment.

Synthesized Questions


  • What are the relative contributions of different sectors to N cycling in California?
  • Are measurements of gaseous losses and water contamination accurate? Do they capture the “hot spots” and “hot moments”?

Management Practices

  • What are the current N rate recommendations? Are current nitrogen application recommendations adequate for present-day cropping conditions?
  • How is nitrogen use efficiency determined and what are the most efficient and inefficient production systems?
  • Are there current management practices that would increase N use efficiency?  What are the “BMP”s for reducing N pollution and increasing efficiency?
  • Are there tradeoffs between reduced N application and other cropping considerations?  Will deviating from current N applications (e.g., form, rate, timing) affect product quality, increase pest pressure, etc? 


  • Can policies better take into account the tradeoffs between the costs and benefits of N use, and to what extent?
  • To what extent would policies designed to reflect the public health and environmental costs of nitrogen pollution affect food prices and farm revenues?
  • How might policy be used to more effectively address point and
    non-point source pollution?
  • What are the hurdles to having a coordinated and cohesive N policy across regulatory jurisdictions?


  • What is the state of knowledge on how nitrogen influences air and water quality and impacts human health?


  • How do we communicate the complexity of the nitrogen cycle and
    nitrogen-related problems to the public?
  • Will N management outreach tools be created that will aid decision making at the field and policy level and educate the public?

Stakeholder Question Tree

Question Tree jpg
A graphical representation of questions the N assessment will answer.

Download the question tree [PDF]

List of original stakeholder questions [PDF]