22 



grass sod without herbicide treatment (Table 8) . Control of quackgrass with 

 either glyphosate or paraquat before seeding into the sod resulted in 

 greater numbers of alfalfa seedlings than did conventional seeding. 



In the seeding year yields were generally lower with sod seeding than 

 with conventional seeding. The difference was greatest with no herbicide, 

 in which almost no alfalfa was established with sod seeding. Where glyphosate 

 was applied prior to seeding, alfalfa established well with sod seeding, but 

 yields were still about 20% less than with conventional seeding. The lower 

 yields with sod seeding were the result of slower development and less vigor 

 of alfalfa seedlings, especially until the first harvest (July 11). 



The differences in yield between sod and conventional seedings largely 

 disappeared the year after seeding, except in untreated plots. There was 

 considerable improvement in total forage and alfalfa yields in plots 

 originally treated with paraquat at seeding. With conventional seeding, 

 alfalfa established successfully and was able to dominate in the second 

 year, whereas with sod seedings and no herbicide application quackgrass 

 was still dominant in the second year. 



May 21 seeding . In contrast to the May 5 seeding, there was no rainfall 

 for 10 days following the May 21 seeding. Yields for the season were, on 

 average, 12% lower than seedings on May 5 (Tables 8 and 9) . As with the 

 earlier seeding date, sod seeding resulted in about 20% lower forage yield 

 than conventional seeding. By the end of the first season alfalfa repre- 

 sented over 90% of the harvested forage from plots treated with glyphosate. 



