Well, maybe I'll go down a different road. I work in water resources as a Civil Engineer. And I've spent a good chunk of my career dealing with the external affects of corn production. What? How can that be? Aren't farmers the best stewards of the land? Yes, and no. Follow along...
First, understand what corn is grown for today. Roughly 40% is grown for ethanol - the stuff we burn with our gas. Thirty years ago we did not burn a lot of ethanol, but obviously that has changed. Ethanol production also results in some feed products for agriculture.
Another 35% or so of our corn goes for feed for livestock. This is the stuff fed to cows, pigs, chickens, etc...
A few percent of our corn goes into direct food production - corn syrup, corn meal, sweet corn, etc... But it is a lot less than most people realize. The rest of the crop, roughly 20+% of US corn, is exported.
I won't get into whether HFCS is good or bad, or whether Ethanol in our fuel is a good or bad idea. Instead, I'll focus on the ramifications of decisions that were made to promote ethanol.
In the area of the country I live in, most of my relatives were farmers (emphasis on were...). Some still are, but things are much different than the were before. Pre-ethanol, Crops were typically grown in a three crop rotation (or more...) Corn, Soybeans, small grains like Oats or wheat, and alfalfa were typically used. Each of the crops affects the soils differently, is planted and harvested at different times, etc... The use of multiple crops provided some diversity, and each of the crops needed different things from the soil, and benefited the soil in different ways. The problem here was that the small grains and alfalfa resulted in lower dollars in the farmers pocket. They were relics of how we used to do agriculture with small farms and small equipment.
Fast forward, and we now need a lot of corn for ethanol that we did NOT need grow before. Where can we get it from? Well, a few places, like:
-Cut our rotations to a two crop rotation to soybeans and corn - cut out the lower dollar producing crops. Which is great, but we lose the benefits of the rotation. Big industry says we can fix that, and walah: Here are our industrial fertilizers, herbicides, insecticides, fungicides, etc...
-Modify the plants through genetics and modification to produce more, adapt to places where it didn't grow so well, etc... And to tolerate the herbicides, etc...
-Put more marginal land into production. In my area, this meant farming, ditching, tiling areas that were traditionally too wet to produce a crop reliably enough, so they weren't farmed. They generally are now.
-Remove the windbreaks planted for wind erosion purposes (remember the dust bowl?) and farm edge to edge on everything.
-Irrigation allows corn to grow in places it never rained enough to grow corn in reliably.
-Advances in equipment, and used of GPS to track yields with increasing precision and to target fertlizer has increased and bumped yields even further.
That all sounds OK, right? Well, so long as you don't look much past your farm, maybe... Row crop farming is hard on the soil from a water resources perspective. In the spring, before the shallow (relatively) roots of corn or beans are set, bare earth can allow a tremendous amount of excess runoff relative to vegetated soil conditions. It also allows a lot of erosion to occur. Some of the applied nutrients are lost in this time period, and end up in the ditches, streams, and rivers... and on to the gulf of Mexico. I know, farmers don't want to waste the fertilizer they put on, but regardless, some of it migrates off...
Some of the nutrients find their way into the groundwater over time. Take a look a the areas that have a high susceptibility to groundwater contamination and overlay it with where inputs from fertlizer are high, and you will see the potential problem. The area I used to work in had an obvious upward trend in nitrate concentration over the past 20+ years... not at "bad" levels yet, but high enough that in some cases blending of municipal water sources was needed to lower the concentration (the solution to pollution is dilution approach...)
Farming more marginal lands, connecting up areas via ditching and tiles that previously were landlocked (and I will fully admit a lot of that was done dating back to the 50s and earlier here..), and now pattern tiling, in conjunction with more land in production results in flashier flows and higher total volumes in our streams and rivers... and they react and start to sluff banks and change shape... and all that sediment goes somewhere (along with nutrients. I can point to many systems here that literally falling apart due to these phenomana - and we spend millions yearly trying to "fix" them and literally could spend billions and not fix the problem.
We could talk about irrigation of crops where they didn't grow before and depletion of aquifers. Or we could talk about the water used in ethanol production itself. We could talk about the incredible transpiration rates of corn that can result in increases of dewpoint of up to 5 degrees... And the ensuing precipitation that can ensue that furthers the cycle of the rivers and streams falling apart...
I'm not naive. Yes, we have to grow our food somewhere. Point being - due to the need to make ethanol, we have increased the amount of corn that has to be grown. And that decision has external consequences... And that's where I struggle with agriculture in our area as it exists today.
We are told homegrown fuel good. Don't regulate us, we are the best stewards of the land. And yet from my experience working with SWCD's, Watersheds and Counties, for every farmer that is a good actor in this arena, there are three that will tell everyone else to pound sand. 'You can't tell me what to do" and the high dollars for corn rule... and that's that. The pattern tiles go in, the ditches get dug deeper, the windbreaks come down. If I don,t the next guy will, so too bad for the guy downstream...
That's my 2 cents...
