Germain - I' m guessing the plot is under an acre - maybe less - deer can mow it down in a hurry if your population is high and there are not alot of other food sources. BUT - with a real wet spring - the countryside id lush with food in PA so I doubt its deer (a cage will tell you for sure). Also, severely browsed clover - will come back strong if protected - try a test cage.

It sounds more likely that the Ph is low, or... the clover was not inoculated, and Nitrogen levels are low, or..... a fertilizer was applied that burned the plot. Its also possible that P & K are low.

If any of these sound possible - let us know - there are courses of action that may help.

PS - you should do the soil test now - you will need it in the future anyhow. take several samples from 4-6" down, mix, dry and submit the sample - it' ll cost like $10.00 and at least you' ll know the " base" field composition.