There are a few different styles of rollers. I see some to 50 feet wide. three sections. Some of the home built one are 14 feet wide. Some also can be filled with water. Since I have only used one once I am far from an expert but have heard some depends on how fast your traveling and how soft the ground is when it is rolled. I think all pea and lentil ground is rolled up here as they are very short crops cut on the groung. Many silage crews only want to work on rolled ground. We are light soiled around here so have to watch for blowingas it does break up the lumps.

 I think on the hay ground that I rolled pushed melon size rocks in. Some guys roll their hay ground every year. I don't.