Compost buffers soil pH

In all of our field trials, compost significantly buffered soil pH .  When soil pH was low-mid 6, compost amended plots raised the pH to low-mid 7, and when the soil pH was closer to 8, it lowered it to mid-7.  Below are two examples from different fields.  Screen Shot 2015-02-05 at 9.10.57 AMScreen Shot 2015-02-05 at 9.14.45 AM