Miscanthus Reduces our Nitrogen Leaching


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In a previous post, I made reference to the “dead zone” in the Gulf of Mexico where the nutrient runoff from the upper Mississippi river system has introduced millions of tons of leached fertilizers into an area of the gulf roughly the size of Connecticut. The scientific term for this process is hypoxia, which is a really a medical term meaning lack of oxygen reaching body tissue. If you’ve ever been up in the mountains you’ve probably experienced a slight case of hypoxia, also known as “altitude sickness”, it also occurs on a more serious level with pulmonary and circulatory issues.

 If you’ve ever been admitted into a hospital (or visited someone who has), one of the first vital signs the doctors will monitor will be your  oxygen levels, checking for hypoxia. This post is referring not to a human patient but rather a very wide swath of our oceans, lakes and rivers and how we are actively choking the life out of them.  

Our Increased Use of Fertilizers
The basic model for the Gulf of Mexico dead zone is caused when nitrogen is leached or drained from the Corn Belt and sent down Mississippi to the Gulf. The nitrogen promotes unnatural rapid algae blooms which consume all the available oxygen, then die, leaving little oxygen left for the natural ecosystem.  The hypoxia-caused dead zone in the Gulf of Mexico is sadly not an isolated event, major dead zones occur in the Baltic Sea, China and more locally in Lake Erie and parts of the Pacific Northwest coast, with many smaller dead zones being found in smaller rivers and lakes. The cause is nitrogen run-off from agriculture, which also adversely affects our drinking water as well.

We’ve increased our use of the big three macro-nutrients (N-P-K) at a rapid rate over the last 100 years. The USDA reports that the overall in nitrogen applied to agricultural fields has increased by 470% since 1960. Coupled with the increase of drained farm land (either clay tiles or newer plastic drainage systems) more and more water is drained from our fields and ends up in the creeks and streams that feed the Mississippi. Increased heavy rainfall events (a nicer way of saying  more and more floods) has only added to this problem by increasing the rate of nitrogen leaching into the surface water drainage. 

Use Less – Pollute Less
Many studies have been performed to study this agricultural run-off issue and the USDA promoted techniques to minimize the actual run-off have had limited to no gains in curbing the issue.  One sure way to stop this problem, that is plainly  apparent to me, is to grow crops that don’t require the amounts of fertilizers, especially nitrogen, that traditional row crops consume. Corn is the major user of applied nitrogen and we’ve been planting more and more corn over the last decade, mostly to fuel our biofuel/ethanol market. Currently, about 1/3 of all the corn grown by U.S. farmers goes straight to ethanol production.

So what do we replace corn with? I’ll tell you that Miscanthus makes a very promising alternative, especially when you look at how little fertilizer is needed to successfully grow it. Less fertilizer inputs means less nitrogen leaching and run-off, lesser dead zones, healthier river systems and oceans, better drinking water quality and ultimately a healthier society (just look at Flint, MI to see the affects of toxic water).

The actual data that supports my ideas was performed by Greg McIsaac, Mark David and Corey Mitchell at the University of Illinois.  I hope to expound on their research in upcoming posts but for now, I’d like to leave you with one number, well actually two numbers. The amount of nitrogen (pounds) leached per year per acre. Corn = 36 lbs/acre year. Miscanthus = 2.7 lbs/acre year. I’m not  a math wizard but that seems like quite a difference to me. 


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