alfalfa to grass in the stand. Substantial variation with location 

 occurred in response to spring-applied herbicides (Table 4) . Grass 

 percentage of forage at the first harvest varied by a factor of 

 four times with glyphosate rates between 1.3 and 1.5 lbs/acre. 



Successful establishment of alfalfa was more consistently obtained 

 with glyphosate than with paraquat. On average, paraquat resulted in 

 establishment of an alfalfa percentage similar to that from 0.7 lbs/ 

 acre of glyphosate (Table 4) . Split application of paraquat was more 

 effective than single application on quackgrass and orchardgrass. 

 Paraquat was also effective as a followup treatment of plants recovering 

 from pronamide treatment, or to temporarily suppress, without sacrificing 

 desirable species such as alfalfa. 



Control of existing alfalfa 



At Pembroke, where there was a relatively dense stand of alfalfa, 

 an attempt was made to maintain existing (old) alfalfa plants, yet enhance 

 establishment of new alfalfa seedlings by reducing grass and weed pressure, 

 Pronamide, applied in the fall, killed grasses and left old alfalfa 

 plants unharmed, but few new alfalfa plants established (Table 5) . 

 Treating with 2,4-D, followed with pronamide, injured or killed much 

 of the old alfalfa, as well as controlling grasses, but relatively 

 little alfalfa was established. Glyphosate applied November 16 had 

 a similar effect. At that time alfalfa had gone dormant, as indicated 

 by drooping stems and yellow and white leaves. Glyphosate applied 

 November 1, however, controlled nearly all of the old alfalfa. It 

 was the only treatment with a significant amount of newly established 

 alfalfa and with which alfalfa stands were improved over those initially 

 present. 



At Lee (University of New Hampshire) fall-applied glyphosate did not 

 affect the existing alfalfa, which appeared to be dormant at time of 

 treatment (Table 6). Old alfalfa at Lee survived treatment with 0.7 lbs/ 

 acre of glyphosate on May 2. Higher rates of glyphosate were required to 

 control old alfalfa on May 2 than on May 16. Apparently, translocation 

 patterns were more favorable, at this location, in mid-May. 



