EFFECT OF SEEDING RATES AND WEED CONTROL ON ASSOCIATED WEEDS
OF BROADCAST SEEDED RICE
BY
Roshdy, A.; Allam, S.A. and Zaher, S A
Dept. of Agronomy. Fac. of 4grjc., Moshtohor, Zagazig Univ.
ABSTRACT
Two field experiments were carried out at the Demonstra—
tjon fields of Kafer Saad Domietta Governorato in 1989 and
1990 seaSons to investigate the effect of seeding rates
(30,40.50,60 and 70 kg/fed.) and some weed control- treat-
meats (un—weeded hand—weeded, thiobenzyl bentaon and
thioberzzyl + bentazon) on weed density in broadcast seeded
rice. Dominant weeds were : Echiaochloa Crus gli”’(L.)
Link and difformis. L. whereas Echinochloa colonum
L. was also present in small numbers and not repeatable in
all replications as well as at different growth stages.
Increasing seeding rates significantly reduced number and,
fresh and dry weights of weeds. Increasing seeding rate from
30 to 70 kg/fed. caused a. significant reductions in number
of total weeds by 85 and 15% in the first season and by 57
and 41% in second season, at 90 and 120 days from ڑowing
respectively. Echinochloa crus jjj was controlled
significantly by thiobeuzyl (2.0 1/fed), however bentazon
(1.5 i/fed.) was not effective in controlling this weed at
different growth stages, i.e.. 30,60.90 and 120 days from
sowing in the both seasons Whereas, c difformis and .
colonum were controlled significantly by both herbicides
Moreover, hand—weeding three times after 30 60 and 90 days
from sowing, as well as thiobenzyl were the best treatments,
whereas bentazon gave poor control of weeds compared with
the two previous treatments
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