Go to this previous thead where i answered a question you had about temperature sensors, it shows what i am using.
http://talk.newagtalk.com/forums/thread-view.asp?tid=641427&mid=5380275#M5380275

 I do have data at the 4 inch depth in the mid row for the rye cover but not for the tilled soil, but have the four and six inch temperatures in the seed slot for the tilled soil and the 4 inch in the seed slot for the rye cover. Give me some time and i will put something together.
 We have a couple of farms that are under center pivots and i manage to get at least one data logger in them every year. Sometimes when the sprinklers pass over the area where the sensors are there is a dip in the soil temperature then it seems to recover 2 - 3 hours later, and sometimes it don't affect it at all.