Book of Extended summaries ISDA

International Conference on Reimagining Rainfed Agro-ecosystems: Challenges &
Opportunities during 22-24, December 2022 at ICAR-CRIDA, Hyderabad
was prepared by tillage followed by SSB with application of broad-spectrum herbicide had
significantly lower weed population followed by zero tilled plots. Increase in weed population
at 30 DAS in zero tilled plots compared to that at 15 DAS may be due to the increase in the
germination of grass weeds from the soil surface, which is a problem in conservation
agriculture. Species wise observation on weeds at 30 DAS clearly revealed the significantly
higher populations of grass weeds in zero tilled plots followed by plots with repeated tillage
and herbicide application. Giller et al., (2009) reported that small-seeded weeds that require
light to break dormancy will likely become the dominant weed species in minimum and notillage
systems, including in the first years of adoption of conservation agriculture. Population
of broad-leaved weeds and sedges were significantly higher in repeated tillage than zero tilled
plots both at 15 and 30 DAS. Repeatedly tilled plots recorded significantly higher total weed
dry weight at 60 DAS.
Various weed management strategies were adopted in the sub plots considering the severe
infestation of weeds viz., Fimbristylis, Cyperus, Leptochloa, Echinochloa, Isachne,
Monochoria, Lindernia and Ludwigia. Pre-emergence application of Pyrazosulfuron @ 0.02
kg ai/ha at 3-5 DAS resulted in significantly lower weed population at 15 DAS in all sub plots
irrespective of the main plots. Application of pre-emergent herbicide reduced the weed
population by 70% compared to weedy check at 15 DAS. Singh et al. (2009) reported that
application of pre and post–emergent herbicides is an effective solution for weed control in
zero-tilled DSR either with residue or cover crops as it produced statistically similar yield to
the puddled transplanted rice. At 30 DAS, weed population in all herbicide applied plots were
on par with that of hand weeded plots. Total weed dry weight at 60 DAS in all the sub plots
with herbicides were on par and significantly higher than hand weeding. In all the herbicide
combinations evaluated, it was observed that sedges were the difficult-to-control weeds
compared to broad leaved and grass weeds. There was 40% reduction in the total weed dry
weight in the weedy check plots with zero tillage compared to that in repeated tillage which
reveals the advantage of zero tillage in preventing weed seed germination.
The interaction of main plot treatment with sub plots was also observed to be significant for
various parameters under study. Comparison of yield in the different main plot treatments
revealed superiority of zero tillage. Yield obtained in zero tilled plots was significantly higher
than that in repeatedly tilled plots (tillage both at land preparation and after SSB). Eventhough
the yield obtained from zero tilled plots was on par with plots with tillage (only at land
preparation), significantly lower weed population in zero tilled plots will contribute to less soil
seed bank enrichment than repeated tillage, which will be observed only after two or three
cropping seasons. In all the main plots, the sub plots with pre-emergent herbicide application
followed by post-emergent application gave significantly superior yield. This yield advantage
Managing genetic resources for enhanced stress tolerance
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