Vol. 16—1962 - NorthEastern Weed Science Society

466
Seed and seedling to~e~ance of lawn.~asses to
certain ~~ass herbicidea!
E. J. Rice and C. R. SkOgle~2
'" Several herbi'cides will seiectively control crabgrass when applied i{
stands of established turfgrass prior to the germination of the crabgrass,seed.
The degree of injury to established grasses has been quite well determine~ . .
under \llanyconditions;.· Very little knOWledgeis avaUableregarding the action
.'of most cra.bgrass herbicides whenappUed to the son p:Hor to seeding turf ..
grasses or when applied to iJJJnature grasses.
There are many instances when it would be desirable to treat soils before
seeding, at the time of seeding or shortly after seeding. This study was undertaken
in an effort to determine, under one set of conditions, how long residues,
toxic to certain perennial grasses, remained in the 80il. A second purpose was
to ascertain the length of time necessary between seeding and treating with certain
herbiCides at various rates.
Materials
and Methods
The test plots were located on a soil that is classed as Bridgehampton
sil t loam. A productive, well-drained soil, it had been fallowed for two
seasons prior to 1961. Fifty pounds of ground limestone and 25 pounds of an
8-6-2 grade fertilizer per 1000 square feet were added to the soil during the
seedbed preparation on June 21, 1961.
Nine chemicals, most of them at two or more rates of application, were in­
Cluded in the test. An untreated check was maintained for comparison purposes.
The chemicals, formulations, and rates at which they were applied can be found
in table I.
All chemicals were applied to each of three grasses - Merion Kentucky
bluegrass (~ praten,is), Astoria colonial bent (Agrostis ~) and Chewing's
fescue (Festuca ~. The bluegrass was seeded at the rate of two pounds per
1000 square feet, the fescue at 5 pounds and the bentgrass at one pound.
Each block or replication consisted of one 28-foot strip, 66 feet long,
for each of the three grasses. Each 28-foot strip of grass was divided into
7 4-foot widths through the entire 66 foot length. These 4-foot plots were
treated or seeded, the fUll length, at each treatment interval. The 66-foot
length was divided into 22 3-foot Widths, each of which received different
chemical treatments. Thus, each individual plot size was 3- by-4 feet, and
there were 462 plots in each of the 3 blocks.
Chemicals were applied according to the following plan:
lContribution No. 1050 of the Rhode Island Agricultural Experiment Station.
2Graduate Assistant and Associate Professor of Agronomy,respectively.