Minnesota Pollution Control Agency recently produced a publication, Agriculture and Water Quality, Best Management Practices for Minnesota. For the most part, this 64-page booklet is simply a re-hash of generic pollution propaganda recommending a variety of farming practices. All these practices, some more beneficial than others, have been broadly recommended by U.S. Department of Agriculture and Soil Conservation Services for years. Now MPCA is also in the farm management business.
One interesting segment in the document is an example of Agricultural Best Management Practices. The objective, as stated in the first paragraph of the example, is to illustrate how a system of several practices are needed to control nonpoint source pollution from cropland. To do this, they used a computer model, "which predicts the quantity of various pollutants that will be carried off an area during a storm."
The test then briefly explains the parameters used in the model.
"To minimize the variables involved, the soil conditions and the cropping sequence were held constant. The soil used was a silt loam soil with a uniform slope of 4 percent on a 260-acre watershed. The crop sequence selected was corn planted after a previous year's crop of corn and the storm evaluated was a 2.3 inch rainfall occurring immediately after the time of planting."
Five systems of combined practices were evaluated. The baseline system, to which the other four are compared, is termed Conventional. This is followed by Mulch tillage, Mulch tillage with contouring, Mulch tillage with contouring - fertilizer quantity based upon soil test, and Ridge tillage with contouring and full nutrient management.
The Conventional system defined by MPCA is:
Fertilizer--High level of fertilization broadcast after the previous year's crop harvest. Nitrogen applied as anhydrous ammonia in the fall.
Tillage--Moldboard plowed in the fall, one disking used for spring seedbed preparation. Tillage operations up and down the hill.
Without going into detail about the predicted benefits of the various conservation practices, it is still easy to expose the fraud being perpetrated by this example. If you use a computer, you probably understand the acronym GIGO, Garbage In, Garbage Out. It's basically the same as: Figures don't lie, liars figure. Let's just see what kind of garbage is in this computer model.
First, we have a uniform slope of four percent (211 feet per mile) on a 260-acre watershed (Not field, watershed. There must be a stream at the bottom that only drains this one hill, which is virtually impossible.)
260 acres is 40 percent of a square mile. If we give them the benefit of doubt and assume this is a square field, each side is 3,365 feet long (about 2/3 of a mile) and the elevation drops 135 feet from top to bottom. It is assumed cultivation extends right to the streambank. If you look at this model as just a 260 acre field with 135-foot slope, you will be able to find some examples of this in the Minnesota River watershed, but not many in relation to the rest of the basin. Most of these will be in the upper reaches of the watershed, along eroding stream banks, or between terraces in River Warren. However, if you take them literally when they call it a watershed, then they are clearly trying to model an entire stream. At this level, their example doesn't exist in the basin.
Next, we add water. To prove erosion, they drop 2.3 inches of rain on the field at a time when it is most vulnerable. This is about a two week window. If this happened, you'd certainly have erosion. You'd also have a flood.
Now, if you think this balderdash is bad enough, let's look at their baseline Conventional system. They load the field with excessive fertilizer and plow as deep as they can. Most importantly, however, they plow and disk the field up and down the hill, creating numerous channels straight from the top of the hill to the banks of the stream.
Yes, given the above example, that stream is going to get loaded with silt and nutrients. Yes, the suggested practices, especially contouring, will probably accomplish some of what they claim. The problem with this example is that it doesn't exist. If nothing else, I don't know anyone who, in 1993, would plow and disc up and down a four percent slope. At the very least, they would probably disk perpendicular to the plowed furrows.
You are being sold a bogus program to cure a nonexistent threat. In the real world, this is considered horribly unscrupulous. If a private business tried it, Attorney General Skip Humphrey would be all over them. We must have the truth. If government will not provide solid facts, it should not be involved at all.