A major benefit of OptiSurface is the ability to solve infield surface drainage without infield ditches and still keep earthworks low.

In my mind, infield ditches (even shallow ones) are far from ideal. Their negatives include:

• require maintenance, 
• reduce crop area, 
• increase weeds, 
• reduce machinery efficiency,
• increase machinery damage (see photo), 
• etc.

None of DAVCO's fields have infield ditches. I wouldn't recommend them unless the topography is so broken that eliminating them requires a lot more earthworks.  

However if you really want them you can add them in OptiSurface Designer if required. This is typically done by adding 'valley' subzones to an OptiSurface 2D design or drawing in breaklines onto the proposed surface.  

Originally posted by Graeme Cox, PhD of Precision Agriculture, BAE, Director of OptiSurface http://optisurface.ning.com/profiles/blogs/why-you-dont-want-ditches-in-your-field