Some tillage is okay, but soil erosion is not
Saturday, August 8, 2015
A provocative book argues that civilizations have died because of soil erosion, implying that farmers should no-till. But it prompts a number of 'yeah buts'
by PAT LYNCH
I have been having some discussion with Ken Nixon, a Middlesex farmer and member of Innovative Farmers Association of Ontario. It started when I received a book called "Dirt: The Erosion of Civilizations" by David R. Montgomery, who was a speaker at last year's Innovative Farmers Conference. At the end of the conference, there were some books left over. The chairperson asked what should be done with the books. Someone yelled: "Send one to Pat Lynch."
"Dirt" is a very interesting read. It is a history of man's abuse of the soil and the author makes a case that many civilizations died because of soil erosion. He states facts to show that, as farmers allowed the soil to erode, production went down and civilizations were lost. The inference is that, unless North American farmers switched to no-till, yields will go down and our civilization will be lost. One specific reference is to how U.S. farmers grew continuous tobacco, which is organic matter negative. After years of doing this, the ground could no longer grow crops. (The closest thing to this that we are doing in Ontario is growing continuous soybeans.)
However, when I read "Dirt," I found myself interjecting with a lot of "yeah buts." First, as I look at the history of crop production, I see it as depleting soils by not fertilizing. Today's knowledge of crop nutrition has allowed yields to increase even with some tillage.
Secondly, as I look at history, it is plagued with governments that ignored agriculture. The Romans are a classic case. They ignored their farmers, made them into soldiers and imported their food. Their own soil became depleted.
A big "yeah but" for this author is that, even though we are doing some tillage, crop yields in North America continue to increase.
There have been many naysayers over the years who have said that we will run out of food. One of the reasons in the late 1800s was because soils were nutritionally depleted. Then farmers started to use guano excrement from sea birds and bats. The first big guano stocks were on islands off the coast of Peru. Guano contains N, P and K.
As this resource started to deplete, new naysayers said that people would starve. Then two Germans, Haber and Bosch, combined to take nitrogen from the air to form nitrogen fertilizer. This nitrogen was needed for the war effort but, after the war, it was used as fertilizer. The process they developed is still the main way nitrogen is now produced. And then P and K were mined to help alleviate the world food shortage.
All of this is background for the question: "Do farmers have the right to work land the way they want?" I have asked this question numerous times when speaking at grower meetings. Generally, the crowd is split. Those who say they do have the right are all farmers. Those who say farmers do not have the right are typically non-farmers, with some farmers agreeing.
We saw what the government has done regarding neonics. Is it logical to think the same bureaucrats will tell you how to work your land? Or, if there is a carbon credit tax, will no-tillers have an advantage over farmers who work the land? Specifically, if a dairy farmer grows three years of alfalfa, plows the ground and plants corn with secondary tillage, will he be judged as adding fewer carbon credits than someone who no-tills continuous soybeans and no-tills wheat once every three years?
The point to all of this is that some tillage is OK and sometimes even essential to make a profit. What is not acceptable is allowing soil to erode. While the government may not tell you how to work the land, they will tell you to reduce soil erosion. Economics will tell you to use crop rotation and cover crops to add organic matter and increase yields. BF
Consulting agronomist Pat Lynch, CCA (ON), formerly worked with the Ontario agriculture ministry and with Cargill.