In ARGYLL rushes and sedges are as big a problem as bracken, do not believe that they only grow in wet conditions each plant can produce a million seeds and will settle any where i have them on knolls that burn in a dry summer. Ploughing will only give the seeds new ground to germinate, you need to kill the plants for 2 to 3yrs before ploughing . Cutting a couple of times ayear has stunted them but they still remain ( i have some in my lawn cut fortnightly still there. Spraying by tractor and quad with MCPA OR 2-4D stunted but stiill there. For me i would take a small spade and some plastic bags, dig small test holes in 5 or 6 places to see the soil stucture and how wet ,take soil from each hole into a plastic bag mixing together and keeping about 2 kg send off to a lab for analysis, the ph is probably very low. I would cut and remove all vegitation , graze the grass to keep it low and wait for the rushes to regrow then use a weed wiper (contractor ) with glyphosate, this is the method i now use with great success, young plants will appear next year so repeat . Correct ph with lime and drain any wet areas. Pigs can do the job but you need to lift and burn the root balls