Amending vs. Fertilizing

Published Jun 16, 2018 

This past winter I spoke at the Pennsylvania Association of Sustainable Agriculture(PASA) and NOFA NJ 2018 Winter conferences. What an honor to be able to talk to so many enthusiastic like-minded people. 

In this article, which was initially published in Week 5 of the 52 Weeks of Agronomy Series, I talked about one of the things I presented on at those conferences. You can find it along with other articles at


I spoke about the concept of amending vs. fertilizing and understanding the differences between the two.  

While it seems like a no-brainer for the seasoned farmer, I have found all too often that basics can be overlooked. It is in understanding and practicing the basics that money is saved and the best crop is grown. 

I have to recommend you get a complete soil test done, including organic matter. Is a soil test the end all be all to a fertility program – no. However, it is the foundation for building a plan to manage the health and fertility of your soil and crops. Getting testing done before fall gives you the time needed to make critical decisions regarding amending and fertilizing, ultimately helping you to get the most financially and environmentally from your fertility program. 

The basic definitions are–

Amendments are used to change the physical & chemical properties of a soil. It is a long-term project that should be carried out over the course of several months if not years. The soil was not created overnight nor will you be able to change it overnight. Soil wants to inherently go back to the characteristics of its parent material. Typically we are growing crops that require a different set of parameters such as pH. Hence, we are constantly making adjustments to the chemical properties of the soil we're farming to ensure we will get the best yield or nutritional value possible. Typically, amendments are applied over a broad scale, like in the case of raising or lowering the pH of a given field. 

Some amendments, as in the case of Biochar, have long-term fertility consequences that need to be considered. Understanding the why, how, and where you are using an amendment and basing it on your soil conditions and type, before using it in a fertility program will ensure you get the most benefit from it. 

Some amendments include limes, aragonite, greensand, mulch, manures, composts, elemental sulfur, peat, coir, rice hulls, biochar, gypsum, Azomite, and cover crops.

Fertilizers are intended to feed the individual crop/plant. Given the source of fertilizer, you can feed and encourage the biology of the soil as well. The right source, rate, time, and placement are critical to ensuring optimal plant use, nutrition, and yields. Fertilizing should be done strategically to reap the most benefit for the crop and help reduce the expense. 

Some common natural or organic fertilizers are blood meal, feather meal, peanut meal, corn gluten, crab meal, fish, kelp, manures, bone char/meal, sul-po-mag, sodium nitrate, Epsom salts, kelp, etc.

Both can look very similar and follow similar principles for application. Having a soil test and the understanding of why, how, and where you are using them can save you money. Having an understanding of the basic concept of their intended use can lead to a more efficient and effective fertility program, ultimately making your farm more sustainable.

Amending vs. Fertilizing

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Monica Pape Annville, PA
Jun 16, 2018
Amending vs. Fertilizing

Amending vs. Fertilizing

This past winter I spoke at the Pennsylvania Association of Sustainable Agriculture(PASA) and NOFA NJ 2018 Winter conferences. What an honor to be able to talk to so many enthusiastic like-minded people. In this article, which was initially published in...

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John Moody Irvington, KY
Jun 21, 2018
Great post and great info!

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Pat Rogers Blenheim, SC
Jun 16, 2018

[@Accidental Agronomist]( Thanks for the writeup. I am continually baffled by long time farmers in my area who still don't see the value in getting your pH right. To me, it's the foundation of farming. An optimal pH leads to more efficient nutrient use which in turn helps us grow better crops (on less fertilizer no less). A good fertility plan that isn't used in combination with a good ph/amendment plan is pretty useless if you ask me.

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Monica Pape Annville, PA
Jun 18, 2018
If you think of the soil as a digester similar to a gut, managing pH to be slightly acidic keeps it operating effectively to assimilate nutrients that are already present or being added in the form of manures and fertilizers. I often explain it as if you are taking advantage of what is inherently present and using what might be added as efficiently as possible. A healthy gut or soil, one being slightly acidic where as good bacteria and fungi flourish does that. pH is the linchpin to creating that environment conducive for healthy flora to thrive.
Often I think we don't understand all the ways pH is useful or even what drives it. It can also be a hard concept to grasp. I liken it to an abacus. You're using calcium, magnesium, sodium, and potassium, etc. balancing pH -hydrogen, to encourage a healthy system. And as you mentioned, grow a better crop with less or no fertilizer.

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