It might not be corn but rather corn ears that are the problem. A friend sent me this link about tropical maize that gets very sugary in the stalk (25%) when grown at higher latitudes. There may be some evidence that Algonquin cultivated this variety for sugar. Corn does not need a lot of nitrogen until it starts to set ears.

Chris

sugary in the stalk

Such should not be shocking - cellulose (way oversimplified) is a complex sugar. And a few old references for making distilled ethynol suggest stalk from sweetcorn.