LITERATURE REVIEW 



Van Keuren and Triplett (21) noted that it is necessary to 

 reduce grass competition with herbicides during no-till establish- 

 ment of alfalfa seedlings. Other researchers have made successful 

 no-till seedings of alfalfa without herbicides, but have found it 

 necessary to reduce grass competition by repeated clipping of the 

 grass just above the legume seedlings (19). 



Paraquat at 0.25 to 0.5 lbs/acre has been widely used to desic- 

 cate and destroy emerged vegetation prior to no-till seeding of 

 many crops (20). Paraquat is most effective on sods dominated by the 

 less vigorous species, such as Kentucky bluegrass, timothy, and red 

 fescue (22) , 



Grasses can be controlled with pronamide at rates of 2 to 3 

 lbs/acre. Pronamide is absorbed entirely through the root system 

 and is subject to chemical degradation in the soil at temperatures 

 above 50F (16) . It is therefore most effective if applied in late 

 fall and moved into the soil by rainfall before the ground freezes. 



Glyphosate provides nearly complete kill of most herbaceous 

 perennial species at rates of 1.0 to 3.0 lbs/acre when applied to 

 the foliage and translocated throughout the plant during periods of 

 active growth (1,17). Quackgrass in the spring is not adequately con- 

 trolled by glyphosate until the three- to four-leaf stage (6 inches) , 

 when the quackgrass shoot directs most of its carbohydrates to the 

 rhizomes. Under these conditions glyphosate will destroy the regener- 

 ative potential of rhizome nodes (15). Previous research (3,10,18) 

 has shown some advantage in delaying seeding as much as one month 

 following glyphosate application. Delayed seeding, compared to 



seeding immediately after treatment, was associated with: (1) more 



2 

 alfalfa seedlings per ft , (2) faster development of alfalfa seedlings, 



(3) greater alfalfa yield at the first harvest, and (4) greater density 



of alfalfa plants the year after seeding. Following the application of 



