I recently posted this picture of amassed corn stalk residue on my The Farmer’s Life facebook page with the description “Water has caused crop residue to accumulate in some areas creating a thick mat. In our no-till fields. We may have to burn a few of these to assist the planter in placing seed correctly.” The first comment on the photo resulted in the post you are reading right now. That comment read “What’s a no till field? Why would you not till a field?” A great question. There are many kinds of tillage including not tilling at all.
What is No-Till? No-till is just what is sounds like. A true no-till system avoids disturbing the soil with tools like chisel plows, field cultivators, disks, and plows. Not all of our acres are no-till, but we have been doing less tillage as of late including putting more acres into no-till. I’m 32 years old and I’ve never actually ran a moldboard plow over a field aside from the single acre we took turns playing on a few years ago in our 1956 John Deere 70 Diesel and three-bottom plow. I might lose some farmer points here, but I don’t even know how to plow a field properly. Lack of experience I guess. A plow could be considered the polar opposite of no-till. A plow flips over the top layer of soil incorporating nearly all residue into the soil. No-till relies on natural processes to break down residue from the previous crop. Advantages
- Reducing fuel, labor, and equipment costs are the most quantifiable benefits of not doing any tillage. Our current tillage system normally includes a fall chisel plow pass to manage residue followed by a pass, or two, with a field cultivator to prepare a seed bed for planting. This system would be called minimum or conservation tillage by some, but right off the bat a no-till plan cuts at least two trips across our ground out of our budget. If we quit doing tillage over our whole farm we’re looking at removing a couple of gallons per acre of fuel from our expenses. Take the price of diesel today times our just over 2,000 acres of farmland and you’ll get a fairly substantial number. That’s also fewer hours on a tractor meaning more value at trade-in time, and less wear and tear on tillage tools. In fact I believe if we went 100% dedicated no-till we could sell off all our tillage tools and downsize one tractor from our lineup. We’ve recently purchased a John Deere 2623VT vertical tillage tool, but let’s keep things simple for now.
- Improved soil structure is another big benefit. Tillage disrupts the natural structure of soil and releases some of the carbon soil organisms thrive on. Soil biology plays an important role in providing crops with the water and nutrients they need.
- Potential for erosion can be reduced by leaving more residue on the surface in the months when there are no crops growing. Residue allows for rainwater and snow melt to infiltrate the soil rather than causing surface run off that will carry away topsoil and nutrients. Of course if enough rains falls on already saturated soils you’ll have some runoff no matter what. We are experiencing those conditions right now.
- Reducing soil compaction is a great benefit. Soil gets compacted any time equipment drives over the surface. The weight of farm equipment compacts the air and water pockets present in soil that allow for the movement of water, crop roots, and soil organisms. Combines and grain carts are the worst offenders because they are very heavy. Since no-till reduces the amount of equipment a field sees the threat of compaction is reduced. Compaction cannot be avoided completely, but it can be managed by limiting field traffic to certain areas. Subsoilers and cover crops can also correct compaction issues.
This piece has gotten fairly wide circulation and deservedly so. I have a few quibbles and observations.
1. You really need to disentangle biotech seeds and problems relating to the pesticide use associated with specific seeds before you explain how they are related. To someone who isn’t already on top of the issues, they are hopelessly conflated in this piece.
The local differences over glyphosate are feeding the long-running debate over biotech crops, which currently account for roughly 90 percent of the corn, soybeans and sugar beets grown in the United States.
While regulators and many scientists say biotech crops are no different from their conventional cousins, others worry that they are damaging the environment and human health. The battle is being waged at the polls, with ballot initiatives to require labeling of genetically modified foods; in courtrooms, where lawyers want to undo patents on biotech seeds; and on supermarket shelves containing products promoting conventionally grown ingredients.
This is the opposite problem from what Amy Harmon was criticized for in her citrus greening piece. Many felt that she did not provide enough context. I disagreed with that criticism. I thought Harmon was wise not to attach a giant boilerplate rehash of the entire GMO debate before moving on to tell the story that she had chosen to tell. Balancing the proper amount of background necessary for clarity and context is tricky.
2. Strom’s choice to use the term ‘biotech’ without ever using ‘GMO’ is an interesting and loaded choice. I’m not entirely sure what to make of it. Is there a move a foot at The Times to tell these stories in a less polarizing way? Not enough data. Stay tuned.
3. I’m sure that this story will fuel Monsanto Derangement Syndrome but it’s not clear to me that there are any clear policy takeaways other than the need for funding independent ag research at our public universities to make sure farmers get the information they need to make good choices.
An article by Dan Charles for The Salt on Bt resistance in the corn belt actually does a good job of identifying the problem as an issue created by poor crop and pesticide management rather than blaming biotech. The insinuation is the title, but not the reporting. The comment section is a battle of bumperstickers vs. balance.
In May, Andrew Kniss asked the world to stop using the term “Superweed” and brought some perspective to the role of biotech in herbicide resistance.
Most of the time, the term superweed is associated in some way with herbicide resistance. So if we define superweed as a weed that has evolved resistance to herbicides, we can then test the hypothesis that “GM crops have bred superweeds.” (ASIDE: The way this statement is phrased, there’s no way it can possibly be true, because crops don’t “breed” weeds. There are some rare cases where crops and weeds cross pollinate, but those have not resulted in any herbicide resistant weeds to date. For the sake of argument, we’ll assume Ms. Gilbert really meant “GM crops have significantly increased the development of superweeds.”) Dr. Ian Heap has developed and maintained a website to document new cases of herbicide resistant weeds, and we can use the data at that site to get an idea of whether this statement is true or false using our definition of superweed.
If GM crops have contributed significantly to the development of herbicide resistant weeds, we would expect the number of unique instances of these superweeds to increase following adoption of GM crops. The figure below illustrates all unique cases of herbicide resistant weeds between 1986 and 2012. I have fit a linear regression to the data from 1986 to 1996 (time period before widespread GM crop adoption) and another regression to the time period 1997 to 2012.
The slope of the linear regression is an estimate of the number of new herbicide resistant weeds documented each year. In the eleven year period before GM crops were widely grown, approximately 13 new cases of herbicide resistance were documented annually. After GM crop adoption began in earnest, the number of new herbicide resistant weeds DECREASED to 11.4 cases per year. The difference in slopes between these two time periods is probably not very meaningful from a practical standpoint. But based on the best data available, we can be quite certain that adoption of GM crops has NOT caused an increase in development of superweeds compared to other uses of herbicides.
Perhaps this definition of superweed is too broad. Let’s define it instead as only “glyphosate-resistant” weeds. The first glyphosate-resistant weed was documented in 1996. This is approximately the same time GM crops were first being introduced into the market. But this first superweed evolved in Australia, where no GM crops were grown. So it is obvious that GM crops are not necessary for glyphosate-resistant superweeds to develop. Certainly, adoption of Roundup Ready crops (the dominant GM herbicide resistance trait) has increased the use of glyphosate in cropland, and therefore increased selection pressure for glyphosate-resistant weed populations. But even so, there are currently more instances of glyphosate-resistant weeds in non-GM crops/sites than in GM crops. The following chart (from www.weedscience.org) illustrates the number of cases of glyphosate-resistant weed species in various crops/sites.
The only 3 GM crops on the chart are soybean, corn, and cotton. All of the other bars represent non-GM systems. If we add up the number of herbicide resistant species in GM crops and compare it to non-GM crops/sites, we should expect GM crops to have a higher number if GM crops are the primary contributor to evolution of superweeds. However:
- 35 species of glyphosate-resistant weeds are present in GM crops (soybean, corn, cotton).
- 40 species of glyphosate-resistant weeds are present in non-GM crops/sites (orchards, grapes, roadsides, wheat, fencelines, fruit, barley).
So again, there appears to be no strong difference between GM crops and other sites where glyphosate is used. So this data again suggest that GM crops are not any more problematic than other uses of glyphosate for selection of superweeds.