Salem

What does the Hoe do when harvesting a field? I know its used to start a field but I've noticed it equips itself from the toolbelt but I haven't really noticed any difference in anything in terms of harvesting a field.

it equips itself whenever you right click a field; i have seen no impact on harvesting fields from them.
You can use them to lower max upkeep, FTR.

Indeed... It is doing this because it wants to be sure that your hoe will not give you the option to lower the upkeep of the field in question. So ti equips the hoe for you and checks to make sure that you have tended it to maximum efficiency. If it determines that it is then it doesn't waste your time with the tend option.

It does feel like there would be a simpler solution to this then parsing your character inventory and toolbelt.... However, with something as labor intensive as fields its nice to not have a 'flower menu' every time you want to inspect a field.