there is no fact sheet I am aware of on this specific topic but an excellent fact sheet from Michigan State Univ. on hops in general discusses mulching and cultivation on pg. 6: http://www.uvm.edu/extension/cropsoil/wp-content/uploads/Sirrine-Sustainable-Hop-Production-in-the-G...
There are lots of videos on mechanical cultivation (google eOrganic weed videos) and for hops you would need one tool for between the rows like a tine weeder or spring tine harrow (unless the rows are in grass) and another for the rows - besides hand hoeing there is a tool that some grape growers use to move in and out of the row - badger weeder I think it is called, but these are pricey and can cause root damage. Heavy mulching with straw or putting down landscape fabric are probably good options. Give me a call or email if you want to discuss further.
Vern Grubinger vernon.grubinger@uvm.,edu or 802-257-7967 x303
UVM Extension vegetable and berry specialist