Vol. 16—1962 - NorthEastern Weed Science Society

If or where farmer acceptance of a chemiceJ. treatment is based on visueJ.
observation or the absence of vegetation, the above treatments would be considered
unsatisfactory even though the yielda may not be affected. 'Including
the cultivated and non-cultivated treatments, 18 )'leld values are represented
in the above treatments rated as poor or fair in control. The yields from 9
of these plots are, however, in the first 20 highest yields obtained in the
experiment. A clear d:l.stinct10n should be made between seasoneJ. suppression,
reduced stands and kill or el1m1nation of quacltgr8ss when writing for or
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are reported in pounds per aereef 20 percent lII01ature hay equi veJ.ent •
The CQrn silage yields were calculated from the harvest of 2 - 10 foot
.ections of row,tuen from the center area of thecml;t1vated and from the
center area of the non-cultivated portions of eaoh treatment. A random I
sampJ.e was ,ara~;f'rom the harvested plants, chopped and a 2,000 gram sample
of chopped :ulaterial was oven dried to determine dry matter content. The
yields of IJilage in tons per acre at 75 percent moisture were calculated
from these values.
Discussion~
All chem:lca]. trea~tson the corn stubble plots (Table I) when combined
withoult:l..vat10n resulted in e. significant reduction in the competitive
effects of~&s as indicatedby' the silage yields. As shown by the
y:te~ds of quackgz!ass foliage '911l1l1l.Dytreatments, however, the effect was dUe
to a reduction in the vigor and jp'OWthof quackgrass rather than effective'
klll.
Whenthe plots were harvested' in September ti1Elre was an excellent cover
of quack8ras. on treatments 3, 5, '6, 10, 12 and to a lesser extent 14. _n
though the yields of s1188e were GOt significantly reduced on these trea1j.
ments, the ~ll of quackgrass was: rated fair to very poor. It is fair to '
assume that had mo:l.sture conditions been less favorable throughout the growing
season, 'the y1elds would have..been reduced by .M¥eral tons· per acre.
A CClZIIliletekill of quackiras.$ is possible by ~ated applications of
plow-down and pre" or post-emergel)ce chemical treatments. The same total
SlIPunt of eJJemical :l.n split applications has been tar more effective in
killing quackgra8s compared to a single application. Where kill of quaekgre.ss
is desired, the cost of an additional spray treatment is Justified.
The silage yields from treatments on the sod area (Table II) are eJ.S().
quite uniform Within the cultivated and non-cultivated plots. A significant
yield difference at the 5 percent level does exist'l\l4!ltween some treatments.
Considering the combination of cClll,POundsand treatments used, however, these
d:l.fferences are small.
Also, based only on the yields obtained from the cultivated and nonoultivated,
the Value of cultivation would be questioned. Visual ratings on
the oontrol of quaekgrasll at the tlme of harvest, however) shewed a definite
adve:atage for cultivation in kill1ng quackgrass. Even though the yields do
not reflect it, treatments 6, 10, 13, 15, 21 and 23 were rated poor control
and treatments 14, 18 and 22 were rated fair control.