Abstract
Conservation agriculture is eco-friendly, economically beneficial and sustainable package of
technologies, but weed is considered as a major constraint in adoption of this holistic approach.
To ensure effective weed control with economic benefit a sustainable package of the herbicidal
weed management strategy needs to be developed for this system. Therefore, two experiments
were conducted at Agronomy Field Laboratory, Department of Agronomy, Bangladesh
Agricultural University, Mymensingh during June 2013 to May 2015 with some available
selected herbicides of rice and wheat to achieve the objectives- (i) to evaluate the weed control
efficacy of those herbicides in rice and wheat, (ii) to study the effect of those herbicides on yield
and economic performance of rice and wheat, and (iii) to examine the residual effect of those
herbicides on the establishment of succeeding crops after rice and wheat in rice-wheatmungbean cropping pattern under conservation agriculture systems. Both experiments were
laid out in Randomized Complete Block Design (RCBD) with three replications. In experiment
1, eighteen treatments were tested in strip-tilled non-puddled transplanted aman rice
comprising eight herbicides (pendimethalin, pyrazosulfuron-ethyl, butachlor, pretilachlor,
orthosulfamuron, acetochlor + bensulfuron methyl, butachlor + propanil and 2,4-D amine)
along with a weedy and a weed-free check in 2013 while 15 treatments in combinations of five
herbicides (pyrazosulfuron-ethyl, butachlor, orthosulfamuron, butachlor + propanil and 2,4-D
amine) along with a weedy and a weed-free check were examined in 2014. The best weed
control was obtained from the treatment with sequentially applied pyrazosulfuron-ethyl,
orthosulfamuron and butachlor + propanil that provided similar grain and straw yields as
weed-free control and gave the highest net benefit among all treatments during both years.
Other treatments that ensured higher net return over weed-free control along with effective
weed control were butachlor followed by (fb) orthosulfamuron fb butachlor + propanil,
pyrazosulfuron-ethyl/butachlor fb orthosulfamuron fb 2,4-D amine, pyrazosulfuron-ethyl/ fb
butachlor + propanil and orthosulfamuron fb butachlor + propanil. Experiment 2 was designed
for strip-tilled wheat with 18 treatments comprising combinations of 8 herbicides
(pendimethalin, pretilachlor, triasulfuron, ethoxysulfuron, pyrazosulfuron-ethyl, carfentrazoneethyl, carfentrazone-ethyl + isoproturon and 2,4-D amine) during 2013-14 and 2014-15. The
study divulge that the pendimethalin fb carfentrazone-ethyl + isoproturon, pendimethalin fb
pyrazosulfuron-ethyl fb 2,4-D amine, pendimethalin fb ethoxysulfuron fb carfentrazone-ethyl,
pretilachlor fb pyrazosulfuron-ethyl fb 2,4-D amine, pendimethalin fb carfentrazone-ethyl and
pendimethalin fb ethoxysulfuron were most effective and economic treatments because of
proving efficient weed control and producing higher grain yield and economic benefit over
weed-free control. Moreover, all the herbicides applied in rice and wheat did not show any
adverse residual effect on the succeeding crops like wheat, lentil and sunflower after strip-tilled
non-puddled transplanted aman rice and on mungbean, jute and sunflower after strip-tilled
wheat under conservation agriculture systems.