UNH LIBfiARV 



3 ^tDDD DDLlfi M7T7 



ABSTRACT 



One of the most important management decisions in planning a 

 sod seeding is the method of controlling vegetation. This report 

 highlights the results of a number of no-till seedings of alfalfa 

 into sod at several locations in southern New Hampshire from 1977 

 to 1980. Various herbicides, application dates, and rates were 

 studied in relation to seeding dates. Only fields with soil sufficiently 

 fertile for alfalfa production were selected for renovation. 



Most consistent and effective control of grasses and broadleaf 

 weeds was achieved with spring application of glyphosate. A glyphosate 

 treatment in early May was superior to an application in mid-late May, 

 measured in terms of seedling density and first harvest forage and 

 alfalfa yield. Fall treatment with glyphosate gave adequate sod 

 control when vegetation was green and actively growing at time of 

 treatment. Pronamide was useful in controlling perennial grasses and 

 was most effective when three lbs/acre or more were applied in the 

 fall. It did not control broadleaf weeds . Treatment with pronamide 

 in the fall, followed by paraquat at time of seeding, improved 

 alfalfa establishment over that from either herbicide alone. Paraquat 

 provided adequate suppression of vegetation only with split fall and 

 spring or split application in the spring. 



Existing (old) alfalfa was more easily controlled with glyphosate 

 when it was 10-12 inches in height (mid-May) than earlier. When seeding 

 was within a few days after treatment, establishment generally improved 

 with glyphosate rate up to 2.0 lbs/acre; 1.33 lbs/acre was adequate if 

 applied at least two to three weeks before sod seeding. 



Delaying application of glyphosate until near seeding time 

 resulted in decreased seedling density and decreased alfalfa yields, 

 in most cases. Alfalfa was most adversely affected by seeding immediately 

 after herbicide treatment on moderately well-drained and poorly 

 drained soils. On extremely well-drained (sandy) soils, alfalfa seeded 

 soon after treatment with glyphosate established as well as when treated 

 earlier. 



KEY WORDS: No Till seeding. Reduced tillage. Alfalfa establishment, 

 Glyphosate, Pronamide, Paraquat, 2,4-D, Seeding date, 

 Quackgrass control. 



