There are many issues facing the modern-day farmer, though most of them are nothing that new. After all, nature has always kept us on our toes in the form of drought, flood, and other extreme events. You would think that with technological advances and increased agricultural acumen, however, we would have taken steps towards reducing the negative effects of nature…. or at least be part of the solution, not the problem. Unfortunately, when it comes to erosion, it would appear that we ourselves are the ones to blame for digging us into a deeper ditch.
Now certainly, erosion has always been in existence. It is not necessarily a man-made problem, but unlike many other agricultural issues, it has come to the forefront largely because of human activity. Nowhere is this more apparent than in the Midwestern United States. Here, soil erosion has grown so extreme that Jerry Hatfield, director of the USDA-ARS National Laboratory for Ag and the Environment, believes that we’re losing, on average, 5 tons of soil per acre per year due to erosion (with higher-end areas losing closer to 100 tons per acre per year).
These numbers by themselves can be a bit staggering, but they become even more alarming when we consider soil replacement rates. Essentially, many believe we’re losing soil faster than soil can be restored , thus, if nothing changes, the situation will only become direr.
SOIL EROSION: DIGGING DEEPER
Let’s get to the heart of the issue:
“(Erosion rates are) all rainfall driven,” says Hatfield. This reality may seem to contradict the above statement that increased erosion is a man-made problem. As seems to always be the case when it comes to agriculture, a closer look into things reveals the greater truth.
Spring is generally the wettest time of year. For the farmer who has, say, a corn and soybean rotation whose fields lay fallow in the spring, there’s no crop present to help transpire the water or protect the soil. Compounding this issue is the practice of conventional tillage which exposes soil, breaks down soil structure and thereby, decreases pore space and infiltration. The result? Runoff which leads to erosion. There are even some studies out there that suggest that erosion increases exponentially as runoff increases.
This information will be of no great surprise to those who have watched our three-part series on soil infiltration. In that series we learned the counter-intuitive reality that no-till soils perform better at infiltrating water than those under conventional tillage, be it moldboard plow or chisel plow.
Still, there is some hope. Seven million acres have already been enrolled in the ¹Conservation Stewardship Program (CSP) in South Dakota alone to reduce soil erosion and improve water quality as of 2017. The reality is, however, that while this is a needed step in the right direction, it’s more of a crawl than a leap. So what can we do? Once again, if our research is of any indication, it appears that the four principles of soil health are needed. This fact isn’t lost on Chad Watts, executive director of the Conservation Technology Information Center in Indiana.
“You protect land from erosion and reduce the amount of sediment you put into streams with these (types of soil health) practices,” Watts says, though he knows changing the hearts and minds of traditional farmers will take more convincing. That’s where Midwest native and soil health specialist Doug Peterson comes in.
“The practice of tillage is more ingrained in most people than their religion,” Peterson says.
The notion that conventional till decreases soil stability, soil function and enhances erosion and runoff is a tough pill to swallow for many. After all, most farmers were raised to believe that the very reason they should use conventional till is to help reduce such issues. Unfortunately, regardless of how strongly we adhere to our beliefs, that does not necessarily make them true. In this regard, Peterson doesn’t beat around the bush.
“There is no agronomic or economic reason for tillage to be justifiable anymore,” Peterson says. “It destroys everything that restores soil function.”
We saw strong evidence of this firsthand in South Dakota when the NRCS’ Jeff Hemenway walked us through an eye-opening slake test comparing infiltration in no-till versus conventional till soils.
“The tilled soil dissolves rapidly (in a slake test),” Peterson notes. “In the presence of rain, without the glues or [root] exudates, the soil particles in the aggregates break loose, and they are very susceptible to erosion.”
EROSION: NOT SIMPLY AN ISSUE OF CONVENTIONAL TILL
It’s become easy for advocates of no-till and regenerative farming to “bully” the idea of conventional till. Once again, however, a closer look at things makes it evident that converting to no-till is not a fix-all. If we must view it in such terms, tillage is not the enemy. If a farmer adopts the first principle of soil health (do not disturb), but neglects the other three, they’re only seeing a fraction of the picture. When it comes to erosion and enhancing infiltration, the second principle of soil health (keep the soil covered) is just as crucial. This is one of the many reasons why cover crops have seen a significant rise in recent years.
When you have a living canopy and live roots directly beneath the soil, you can reduce runoff head on. Instead of bombarding the soil, rain hits the canopy and slowly trickles down the plant into the roots. This slow-down effect on raindrop impact is one of the chief benefits of the third principle of soil health (keep a live root in the soil as many days as possible). The result is infiltration as opposed to runoff and erosion.
In this way, it seems rather evident that the solution to high erosion rates comes through the application of principles of soil health. Specifically, through the use of no-till, diverse rotations and cover crops (i.e., no fallow periods) which keep the soil covered and keep a live root in the ground year-round, we address the core issue that runoff and erosion are simply symptoms of: degraded soils.
“Your soil is more than just the medium in which you grow plants,” Watts says. “The downfall of many civilizations was when they degraded their soil to the point that it was no longer productive. When soil degrades to the point of no return, that’s when civilizations begin to fail. It behooves you to protect your soil.”
Join the revolution,
– Barrett
¹ Conservation Stewardship Program (CSP): CSP helps farmers build on their existing conservation efforts while strengthening their operation. CSP is the largest conservation program in the United States with 70 million acres of productive agricultural and forest land enrolled.
To learn more about conservation practices, visit the NRCS’ Soil Health Page.
For more information about USDA NRCS programs, visit the pages below:
Environmental Quality Incentives Program
Conservation Stewardship Program
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SOURCE: http://www.agriculture.com/crops/conservation/erosion-treat-the-problem-not-the-symptoms