Abstract:
Rice (Oryza sativa L.) is an important economic
food crop in Sri Lanka. Weeds are a major
constraint to the success of rice production. Cropweed competition has a profound effect on the
grain yield of rice. However, using herbicides
alone may not be considered sustainable in the
long term. Hence, a field experiment was
conducted at Rice Research Station,
Sammanthurai to study the interaction between
seed rates - weed population and yield
performance of field-grown At362 rice variety.
The treatment (T) consisted of six seed rates viz; 2
bushel/ac, 2.5 bushel/ac (as control), 3 bushel/ac,
3.5 bushel/ac, 4 bushel/ac and 4.5 bushel/ac. The
field experiment was laid out in Randomized
Complete Block Design (RCBD) with 6 treatments
having 3 replications. Field data were collected
on weed populations, rice crop growth and yield
parameters throughout the cultivation season
under field conditions. According to the results,
plant height, the number of leaves per plant, root
length, panicle length and number of panicles
were significantly (p<0.05) affected by different
seed rates. Lower seed rates resulted in increased
values for the above-tested parameters in the
At362 rice plant. Sedges were the most dominant
weeds in this field plot compared to grasses and
broad leaves. However, no significant differences
were observed in the yield and weed population
(p>0.05). Further research in various seasons
and regions can offer a more thorough
comprehension of the relationship among rice
seed rates, weed dynamics, and yield.
