Which crop (intercropping)suits best in coconut and doesn't effect the yield of coconut?

I am from erode,Tamil Nadu …I have 2.5 acres of coconut farm…which crop can be intercropped in this

Growth an yield of intercrop depends on age of coconut plants which is inturn related to light interseption

This should help - http://agricultureforeverybody.blogspot.in/2016/09/intercrop-details.html