Vol. 16—1962 - NorthEastern Weed Science Society

Code
A - seeded June 29
B - seeded June 29
C - seeded June 29
D - soil treated June 29·
E - so11 treated June '29
F - soil treated June 29
G - soil treated June 29
treated 2 week~'later 7/12/61
treated 4 weeks later 7/28/61
treated 9 weeks,later 8/30/61
. seeded - same d~y 6/29/61
seeded 2 wee~s Jat,r 7/12/61
seeded 4 week,SJater 7/28/61
'seeded 9 week$~ater 8/30/61
The test,area was irrigated fre~ntly throughout the season to assure adequate
moisture for germination and'gtowth of the gi~ses. The grasses were cut
at a height of 1 1/2 inches as need~' following esta,plishment. Clippings were
removed when they were excessive.'
'
Those plots seeded 2, 4 or 9 weeks after the solI was treated were hoed and
raked 1ightl y prior to each seeding date. This most"ce~tainl y caused some mixing
of the chemical with the soil. It was necessary~however, to remove annual
weeds and to loosen the so11 surf8~e to prepare a sa~isfactory seed bed. In all
cases seed was spread with a mechanical spreader. Chemicals were weighed or
measured in amounts required to treat individual 3-~~ foot plots with the'ex~
ception of treatments 20 and 21. These chemicals were applied with a mechanical
spreader .• DrY.formUlations were mixe.dwith one Pint,.~ef dry sand and applied by
hand. The liquids were added to one pint of water ('1't>0gal s/A) and applied with
a hand spra~r at 30 pounds pressure. r'
Grass response to chemical treatment or treatmeQ~ interval was determined
by comparing the growth of grass on the treated plot, with that on the checks.
Assuming that, inmost cases, the stl!nd and vigor of,fihe grass on the untreated
plots to be 100 percent the grass on'the treated was~scored from 0 to 100 percent.
The scoring was done from 2 to 4 weeks follow~ng treatment. This depended
on the length of time required for the slowes1;.grass to attain sufficient
growth to be properly scored. '
Twoor three suosequent read'1ngs were taken dur~~9 the season to determine
whether the initial injury was of a temporary or pe~ent nature.
ReSUlts and Discussion
Table I presents the average 'turf ,scores, based 'ondensity and vigor, of
the three grasses when seeciing was done at various in'l;ervals following the'application
of the herbicides to the S()~l. The averag~,;turf scores on the th1'ee
grasses receiving treatment at va~i()us intervals aft~ seeding are given in
table II. These scores are forttie'first readings ta,~en on each plot.
The scores for each grass at ea~h interval were~ubjected to analysis' Gf
variance and the least significant difference at the ~ percent level was ob-'
tained. This information is also given,in tables I .~ II.
, With only a few exceptions chemical treatment re$ulted in some reduction
~ in stand or vigor of the grasses. ',There are a few general observations that
can be stated regarding the results obtained in this study.
467