Environmentalists in Iowa are trying to push through a ban on the use of manure to fertilize soybean crops.
I dunno. When you ban the application on only one crop, you're obviously dictating something more than the proper production of just that one crop. In fact, as indicated in the linked article -- and according to a number of farmers and agronomists I have known -- soybeans actually gain nutrients from manure (think about that the next time somebody offers you tofu). The trick is, as always, in the application.
Also, crop rotation alone doesn't guarantee the soil will replenish itself, from one year to the next. One year of soybean growth in a field may not be enough on its own to help produce a healthy crop of corn the next year (and corn is a very nutrient-hungry plant, indeed). Plus, there are many ways to cleanly poop on plants (really!). If the farmers are given incentives to practice safe fertilizing techniques using manure, the state won't have to effect a ban on its use.
Honestly, this measure sounds to me an awful lot like the first step in banning the rearing of livestock for any purpose. After all, processing manure and applying it to the fields is one very practical way to use the otherwise unpleasant by-product of cattle, hogs, etc. First, you ban the use of poo, then you file complaints about the acccumulation of or the burning of said non-spreadable substance, then you shut down the business which produces said fecal matter.
It may be more than that, of course. It may be that, deep down in their plans, they already know this will be the result of legal limits to the application of manure. They recognize that, with the forced closure of "polluting livestock and dairy farms", only the extremely wealthy, therefore, will be able to eat steak and ham and chicken and eggs and cheese pizzas and quesadillas and ice cream and other such culinary wonders. To hell with the foie gras fuss. It will force the rest of us to become vegans, eating tofurkey.
It could all be an evil leftwing vegan plot-- one simple legislative act against crap on soybeans turns all our lives into crap, instead.
Or, maybe the environmentalists pushing this act are just ignorant a$$holes.
I don't really know them, so I can't say.