Tufts OpenCourseware
Authors: Kathleen Merrigan, Ph.D., William Lockeretz, Ph.D.


  • National Research Council. Soil and Water Quality: An Agenda for Agriculture. Chapter 11. Manure and nutrient management. 1993.
  • University of Minnesota. Hog manure: Gunk or gold? no date.

Key Questions

Nitrogen Export from Agricultural Landscapes

  • What factors influence the export of plant nutrients from agricultural fields?
  • In which form is nitrogen mostly exported from the farms? What are the reasons?
  • What are the different options available for a farmer to prevent nutrient loss from his farm?
  • Can you think of additional factors that a farmer might consider before adopting any of these measures?
  • How do water bodies – artificially constructed or natural – help in the management of nutrients that are exported from the farms?

Costs and Benefits of Decreasing Agricultural Nutrient Export

  • What are the advantages of reducing nutrient loading of water bodies because of fertilizer usage in agriculture?
  • What does a farmer look for while considering the best management practice ( BMP) which might reduce agricultural related water degradation?
  • What is the trade-off involved while modifying agricultural ( especially N usage) practices to enhance water quality?
  • Is public opinion supportive of the farmers in relation to the hypoxia problem in the Gulf of Mexico, even though farming is a major source of the problem?
  • Which conservation policies we are familiar with from ASPI would be relevant in the context of reducing nutrient flow from farms?

Manure and Nutrient Management

  • Why is manure, once considered a resource now termed as waste?
  • What are the advantages of manure application in farming?
  • What is the pattern of nitrogen release from manure?
  • How can manure application lead to imbalance in the amount of phosphorus supplied to the soils? Why is this important?
  • Which agency regulates manure production and disposal of manure from point sources?
  • Do EPA regulations provide adequate protection to both surface and ground water pollution risks from manure produced at point sources?
  • What are some factors to consider while evaluating manure management from point and nonpoint sources?
  • What are the recommendations of the authors for environmentally safe management of manure?
  • What are the alternative uses of manure?
  • How does manure application affect crop yield?