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Solution in the soil? Farming for a cleaner gulf

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Rick Lee decided to enroll in the new program to reduce nutrient runoff from his 1,200-acre corn and soy farm. He's tried planting cover crops for the first time this fall. (Photos by Kathleen Masterson)
About the author
Reporter, Iowa Public Radio
Kathleen Masterson was a Harvest reporter, based in Ames, Iowa, from 2010 to spring 2012.

In the Gulf of Mexico there’s an area about the size of Massachusetts called the dead zone. It’s caused by excess nutrients in the water, much of which comes from fertile farmlands in the Midwest. These nutrients foster the growth of algae blooms, which use up all the oxygen and prevent other creatures from living in those waters.  

Government officials, researchers and farmers alike have known about this problem for some time; the dead zone was discovered in 1974. But despite some federal and local efforts, high nutrient levels haven’t been getting much better. Now a new federal program is striving to reduce nutrient runoff into the gulf.  It starts way upriver, in the fertile farmlands of the Midwest.

The problem

Dig a little deeper

The darker regions show watersheds with high levels of nitrogen pollution.  The squiggly grey lines represent the 818 watersheds that flow into the Gulf of Mexico. (U.S. Geological Survey)
 
Nitrogen in the Gulf of Mexico

Seemingly inconsequential narrow ditches criss-cross throughout many Midwestern fields.  These tiny waterways flow into creeks, which flow into rivers, which flow into the Mississippi River. As these waterways run toward the gulf, they sweep through some of the most productive soils in the country.

The problem is that to produce the country’s wealth of food, many farms apply heavy amounts of fertilizers, which include nutrients such as nitrogen and phosphorous. What the crops can’t use washes off the fields, and into the waterways.

“The erosion — I can remember back in the early ‘60s when there were times you couldn’t see very well; and you’d have mounds of soil sanding in road ditches. It was a sickening thing to witness, really. Just you knew it was wrong,” said Arlo Van Diest, of central Iowa, who’s been farming for nearly 50 years.          

What Van Diest noticed on his property adds up to a much bigger problem. A federal study found that 40 percent of the nitrogen that reaches the gulf comes from the upper Mississippi River basin — basically from Missouri northward. 

Working toward a fix

Van Diest decided to give up intensive plowing on his corn and soybean farm. Plowing churns up the earth and allows much of that nutrient-rich soil to wash away, polluting waterways. He ultimately adopted a method called strip till.  Rather than plowing everything under, he churns a strip a few inches wide down each row.

“We end up with just an entirely different soil structure. It takes a while. It takes four or five years. You just feel the difference,” Van Diest said.  “Actually in the tractor, doing tillage work, you can just tell that our soil is much more mellow and loose.”

But strip till only addresses part of the problem.

Most nitrogen pollution occurs underground when itleeches out of the soil.  The nitrates seep into groundwater or are even directly piped into waterways through field drainage pipes. 

That’s why Van Diest also plants cover crops such as rye and oats. These plants suck up the excess nitrogen, and their roots help hold the soil in place over winter and spring.   

Van Diest is a real convert.  Strip till has saved him money, he said, because he doesn’t have to run his tractor across his fields multiple times, dragging heavy equipment and using expensive fuel.  And he does it to be a better steward for the land.

“I think it’s something all of us are a little concerned about, and all of us really wonder when the government  is gonna say, we’re polluting water too much,” he said. “I think it’s just time to get on board and to do some of these things ourselves instead of waiting for somebody else to crawl up and suggest we do that.”

Money helps to walk the walk

Just last year someone did crawl up and suggest it. The federal government started a new program called the Mississippi River Basin Initiative. It pays farmers sizeable subsidies for adopting methods such as strip till and planting cover crops.  

It specifically targets watersheds in 12 states with heavy nitrogen and phosphorous runoff.  

The program pays farmers more than $100 per acre for a maximum of 320 acres.  It costs about $40 to plant the cover crop and then kill it in the spring. So, depending how much a farmer has to spend on new equipment or unforeseen challenges, he could make a profit.    

Van Diest recalled his reaction when he heard about the program:  “I said you don't need to subsidize me for strip till, it'll stand on its own … but I did go ahead and take it.”

Though only part of his property qualifies for subsidies, Van Diest practices strip till and cover crops on all his land, both for the soil benefits and for land stewardship reasons.

The amount of money available for Van Diest’s area, a sub-watershed of the Boone River, was quickly allocated.

“Some of them said they should have jumped right on it, when they found out what it is,” said Bruce Voigts, who is the initiative’s project coordinator for the Boone River sub-watershed.

“And I think when they see the green fields this fall, late fall, and even into early winter when the rye stays green, they're gonna see notice it, say, ‘Hey, that sounds like good idea, I’m gonna look more into it,’ ” he said.

Testing new ground

Rick Lee didn’t really have time to think about changing his farming practice this fall — he was too busy farming.  Lee had machinery to fix and a flooded house to deal with.  But his landlord heard about the Mississippi River Basin Initiative and asked him to consider it; the acres she rent Lee fall into one of the targeted watersheds.

“I actually thought it was going to be a lot of work until I got to doing some of the studying,” said Lee. “The more I studied it, the more promising I think it is for everybody, and for the environment. And there may be some benefits that I’ll receive out of it, too, I’m sure.”

So Lee enrolled about a quarter of the 1,200 acres he farms in the program, and he just recently seeded his fields with the rye cover crop.  Within a week of the aerial seeding, the tiny reddish shoots with delicate green leaves are stretching up from where they fell on top of the soil.    

Cover crops and strip till plowing are new for Lee, and changing methods is always a risk for any farmer.  Lee said he is anxious to see how things will go in the spring.  

The research

Small-scale experiments have shown that these practices do work.  But some big questions remain:  how many farmers in a watershed need to change to make impact? Will these changes really make a measureable difference on the Mississippi River – and ultimately the Gulf of Mexico’s dead zone?

To get a better understanding of whether these practices are improving water quality, researchers are monitoring nitrogen runoff in tiny creeks all the way up to bigger tributaries. 

They say smaller waterways should clean up first. But it will be years before they can tell if it’s actually reducing the size of the dead zone.