Abstract:
A field experiment was conducted at Cropping Systems Research
Centre (CSRC), Karamana, Thiruvananthapuram to evolve a suitable
integrated weed management practice for lowland nee. The study was
conducted during the viruppu season of 2003.
The field experiment was laid out in randomised block design
having three replication with twelve treatments. The treatments include
different herbicides in combinations, herbicides + hand weeding, hand
weeding twice and unweeded control. Butachlor, 2,4~D, pretilachlor,
anilofos + 2,4-DEE, anilofos, ethoxysulfuron, metsulfuron methyl and
chlorirnuron- ethyl were the different herbicides used in the experiment.
The rice variety used for the experiment was Kanchana.
The results of the study revealed that grasses, broadleaved weeds
and sedges competed with the rice crop. Different weed management
practices significantly influenced the intensity and distribution of weeds ...
The lowest dry matter of weeds was recorded by anilofos +
ethoxysulfuron followed by one hand weeding which was on par with
anilofos -+ ethoxysulfuorn alone.
All the weed management treatments resulted in improved yield
attributes and higher grain yield compared to weedy check. The plots
treated with anilofos + ethoxysulfuron followed by hand weeding at 40
DA T recorded the highest grain yield. This treatment resulted in enhanced
plant height, number of productive tillers un', LAI and nutrient uptake of
rice. The yield attributes and grain yield were significantly increased by
this treatment. The total weed population, weed dry matter production and
nutrient removal by weeds were also reduced and weed control efficiency
was increased by this treatment. Unweeded control recorded the lowest
gram yield. No herbicide used in this experiment resulted m residual
toxicity after the cropping season.
Manual weeding is expensive, laborious and time consummg.
Labour non-availability at peak crop season for weeding also poses great
threat. Readymix application of anilofos + 2,4-DEE (T3) resulted in highest
B:C ratio of 1.41 and butachlor + 2,4-D (T,) with 1.40. Pre-emergence
application of anilofos + ethoxysulfuron followed by one hand weeding at
40 DA T (T 8) was the most remunerative treatment.
