You are here:  Home  >  The Classic by NatGLC  >  Current Article

Can We Replace Man-Made Fertilizers With Manure?

By   /  November 16, 2020  /  3 Comments

    Print       Email
Andrew McGuire is an agronomist working in the Columbia Basin’s irrigated cropping systems. His cu
    Print       Email

About the author

Publisher, Editor and Author

Kathy worked with the Bureau of Land Management for 12 years before founding Livestock for Landscapes in 2004. Her twelve years at the agency allowed her to pursue her goal of helping communities find ways to live profitably AND sustainably in their environment. She has been researching and working with livestock as a land management tool for over a decade. When she's not helping farmers, ranchers and land managers on-site, she writes articles, and books, and edits videos to help others turn their livestock into landscape managers.


  1. emily macdonald says:

    The nutrients in inorganic manufactured fertilizers also come from someplace else, as John Marble points out. Florida, Idaho, North Carolina and Utah extract and process 10% of the world’s rock phosphate used in the manufacture of fertilizer. Canada has the world’s largest deposit of potassium- containing salts mined for fertilizer production. All of the forms of inorganic commercial nitrogen fertilizer are derived from anhydrous ammonia which is manufactured by reacting nitrogen gas derived from the air and converting it by pressure to a liquid state which requires a lot of energy.

    The earth’s supply of extractable P and K are not infinite and inorganic manufactured fertilizer may become as scarce as manure. At least manure is renewable( to the extent grass will grow to feed animals) does not acidify and salinify the soil, and supports rather than destroys soil organisms. If you must transport nutrients from areas of plenty to areas of need in order to grow food, it may as well be manure.

    The big question that people have been trying to solve for eons is how to produce food in a way that does not catastrophically deplete soil nutrients. Can we feed ourselves within the limits of the nutrients the earth can sustainably provide?

  2. red Slusser says:

    Not enough manure? Grow your own. Before a crop comes off, plant a cover under it. This was custom until chemicals came along. How do agronomists think there are fields in production for centuries? Light tillage and post-harvest grazing. All I’ve ever seen chemical fertilizer do is make plants tastier to insect pests. If Gabe Brown in ND can take his soil from 1.5% organic matter to 11% in some fields, then anyone can. He receives average 16 inches of moisture a year and gets record crops without irrigation or chemicals.

  3. john marble says:

    Thanks for this.
    I also exhibit little evidence of being a mathematical genius, but the math here seems almost extraneous. It seems to me that the physics here are pretty basic: we can only increase nutrients in our soils by bringing them from somewhere else. I suppose a philosophical exception might be the collection of N from the atmosphere by legumes.

    I remember my cognitive dissonance when I visited an organic farm where the operators were using a 3/4-ton pickup to drive 70 miles to load up chicken manure that had been processed through a grinder mill and stored under cover until dry. They would then haul it home and carefully spread it on their fields. The explanation for this process was that the farm would not function without all of that transfer of nutrients. I’m happy they have found a way to grow food, but the system seems impossible to sustain.

You might also like...

Fencing Solutions You’ll Like

Read More →
Translate »