There is no way it is a good idea to burn fields for food production – especially for a nonessential food. I made the graphic below to illustrate how relatively thin our atmosphere is. I think it makes the point. Unnecessarily dumping toxins into the air we breath is just nuts.
Unfortunately, this is done for sugar production on Maui by Hawaiian Commercial & Sugar Company (a Division of Alexander & Baldwin, Inc.). In addition to burning the plants, polyethylene plastics used for drip irrigation are burned. A&B contends that burning these plastics do not produce any harmful compounds.
Since the company is phasing out sugar cane as a crop, this article will probably be the extent of my activism to end this. However, A&B is working to find more economical crops. This is good, but if they continue polluting the atmosphere as part of their agricultural process, I intend to put more effort into ending this.