Fire can and will get out of control quickly, and should only be done under the right conditions.
Just a suggestion, but if you can buy/rent a single shank sub-soiler and make passes every 2 feet, you will find it will help with tillage greatly. Sub-soiling, when done right will "shatter" the ground 12" deep, opening up all sorts of cracks which will allow rain to penetrate your soil deeper, making it easier to till and will give you water deeper in your soil, vs having it run off.. SS when it's too wet and you won't shatter anything. SS when it's too dry and you might not be able to get it in the ground and will take a lot of horsepower. When done, wait 8 weeks and several good rainfalls and then disk. Preferrably do this in the spring.
The right conditions have to take place to be successful, but sub-soiling is great vertical tillage. You will be amazed.
http://www.everythingattachments.com/Fred-Cain-Tractor-Subsoilers-s/75.htm
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