What kind of soil do yo have, soil issues your having, kind of weeds your worried about.
You can use clethodim to battle grass in a clover field. Certain broadleaf weeds, you can spray a crop of cereal grains with 2,4D, but will harm clover. A spring light spray of gly onto clover will kill alot of young annual weeds from seed.
After a treatment (s)of 2,4d or cleth, you can spray some gly and put buckwheat in. Barley I believe alopathic properties too . Barley is also about the best cereal for soil bacteria health too. Others know alot more on the issue. A bale of Barley is heighly regard to keep pond water healthy and algae free.
Some of this is from experience, some is from reading other experiences on here. Not sure if it was foggy or someone else did a very good writeup on rye clover rotation and use of gly.
USe of canola, sun hemp, vetch, and cowpeas has given good results too. One of the best tools is a sprayer at the right time combined with ID'ing what your actual problem weeds are too.