Who was the inventor of the steam plow?

There is some conflicting information about this. Here are some of the contenders:

• Edmund C Bellinger (first designs 1833)
• John Fowler (first designs 1852, patent 1852, successful demonstration 1854).
• Obed Hussey (demonstration 1855)
• Richard Gatling (patent 1857)
• Joseph W. Fawkes (demonstration 1858)

Whether or not any of these men is the very first inventor, it is sure that they all contributed to the field.