There is a danger in planting corn over and over again in the same field. If the crops are never rotated, the soil quality suffers immensely, which is why farmers usually rotate their crops from year to year. However, many are expecting that the high prices that corn has been generating, which may or may not be the fault of ethanol, might prompt farmers to continue to plant that crop without switching to others. I am not so sure that this is a real problem yet, and I don't think that there is enough data available to back up the claim. But, it is not too early to think about alternatives, which is what this article is prompting.
Alfalfa indeed would produce less ethanol than corn. Even corn is not a good choice if the amount of ethanol per acre is considered, but that doesn't seem to be on the minds of decision makers these days. Alfalfa is mentioned as an alternate crop because of the positive effects that it has on the soil, replenishing it for the following crop of corn. Most of us would rather see the corn go back to food production, but perhaps the alfalfa would feed the cattle that is missing out on their usual corn-based diets. The real point is that corn is not the only source that the United States can use to generate their alcohol fuels, which are being mandated by the government.
[Source: Earth Portal via Treehugger]