This kind of “aid” shouldn’t exist at all.
Most of this grew out of the Federal Governments efforts to control prices during the Great Depression. The wanted lower prices or higher prices depending on which perceived problem that they wished to fix on any given day.
As laid out in a famous Supreme Court decision in 1942, the Federal Government was given vast powers to regulate economic activity ever since.
http://en.wikipedia.org/wiki/Wickard_v._Filburn
The barn door was opened and it hasn’t been closed since. Politicians have jumped in with glee in order to advance their political ambitions. Republicans tend to prefer putting money into the pockets of farmers and Democrats like to go for subsidized or free food products into the hands of low income city dwellers. The schemes are varied and complex, but there is no shortage of pigs at the trough. These guys are pikers, but the government needs to make an example of the occasional small fry in order to perpetuate the myth that these programs are benificial and promote the general welfare.
Farmers can’t plant whatever they want, they have to conform to government regulators and in return they get a handout for letting the government control their livlihood. The major benefit is to the career politician.