February 26, 2014 Pat Beaujot
The Nitrogen Debate in No-Till
Recently there has been a bit of controversy over an article published in the January 23 issue of the Western Producer. In it, a soil scientist named Dave Franzen, claimed that in long term zero-till fields he observed up to 50 lb. /ac. more nitrogen available each year than in a conventionally tilled field, and went so far as to encourage long term zero-till farmers to reduce their nitrogen levels by 50lb./ac. for cereal grains in North Dakota. A farmer by the name of Mark Jennings supported his claim, saying that he had observed the same thing on his farm.
In nearby Manitoba (just across the border), experts were concerned by this claim, and though Franzen and Jennings were seeing higher protein and better crops in their research and in the field, they were concerned that a 50lb. reduction was extreme, and possibly some hasty advice.
An article by Tom Weir, an agronomist and consultant from the Yorkton, SK area in the December 12 edition of the Western Producer made a similar claim about protein in grain. He cited that there are 10 lbs. /ac. of nitrogen mineralized each year for each % of organic matter in the soil. That means if you have 5% organic matter in your soil, you can expect to see 50 lbs. per acre mineralized that year.
This reminds me of a well-documented claim made by the late Dr. Guy Lafonde, who conducted long term research showing that organic matter increases as you zero till, and if zero-tilling helps the nitrogen cycle, then you can expect to see more nitrogen available in zero-tilled soil and this makes good sense. After four or five years of zero-tilling, you can count on having more nitrogen. The longer you do it, while keeping a good crop rotation and building organic matter, the more you can expect out of your soil.
I think that putting a number on the amount of nitrogen that can be reduced is risky, as conditions will vary from place to place, and the amount of nitrogen in the soil will vary from no-till operation to no-till operation. We all know that the same guidelines don’t always apply for everyone. The important thing to get out of these articles is the overall message that soil health is increased by zero-tilling long term, and that is a good message. You can achieve quite high protein and a quite high yield at the same time.
When I was farming, it was not expected to get high protein wheat on a fifty bushel crop in a conventional operation. With the switch to zero-till and pulse crops into the rotation, with average nitrogen rates I could get over fifty bushels and still get over 13.5 % protein.
When I sold fertilizer in the late eighties and things were tight for farmers, it was about how much a farmer could afford to spend, rather than how much a crop might need. The grower had to balance what he could afford with his or her yield goals. Having that extra buffer of soil health from zero-tilling can do a lot for cash flow when money is tight.
We’ve had a few good years but now commodities have come down and nitrogen prices are extremely high. There is a growing worry over those additional costs eating into what will likely be smaller profits going forward. However, if you’ve been zero-tilling for ten years, then you have that buffer in the soil, and in my opinion that makes you a smart farmer. If the numbers are accurate, 50 lbs. of nitrogen is worth roughly 25-30$ per acre right now, and that will translate to a significant savings. That is just another reason to zero-till and to keep zero-tilling. Building your soil will help you every year, and if you do have a tough year-you will be able to afford to cut back on nitrogen if you need to. I wouldn’t recommend cutting back if you don’t have to, as fertilizer usually means a higher profit, but if there comes a time when you can’t afford it, it’s good to know that you can rely on your healthy soil.
Having extremely healthy soil is like having a healthy bank account! The articles I refer to can be found at the following links: