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Dry seeded rice (Oryza sativa L.) productivity and weed dynamics in relation to cover cropping, tillage and weed control

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Title Dry seeded rice (Oryza sativa L.) productivity and weed dynamics in relation to cover cropping, tillage and weed control
 
Creator Singh, Manpreet
 
Contributor Bhullar, M.S.
 
Subject weeds, crops, sowing, rice, developmental stages, tillage, control methods, yields, land resources, biomass
 
Description The present investigation entitled “Dry seeded rice (Oryza sativa L.) productivity and weed
dynamics in relation to cover cropping, tillage and weed control” was conducted at Students’
Research Farm, Department of Agronomy, Punjab Agricultural University, Ludhiana, in the kharif
seasons of 2012 and 2013. Experiment I was conducted to determine the extent of yield loss in two
different rice cultivars (PR 114 and PR 115) with different periods of weed interference for which 12
weed control timings were used to identify critical periods of weed competition in dry-seeded rice. In
Experiment II, 2 levels of cover cropping (Cover crop and No-cover crop) and 2 levels of tillage
(Coventional and Zero tillage) in main plots; and 6 weed control treatments (Weedy check, Weed free
check, Pendimethalin fb bispyricac, Oxadiargyl fb bispyribac, Oxadiargyl fb fenoxaprop and
Oxadiargyl fb fenoxaprop fb ethoxysulfuron) in sub-plots were tested to evaluate the effects of tillage,
cover cropping, and herbicides on weed growth and grain yield of DSR Both the experiments were
laid out in split plot design with 3 replication during both the years.
PR 114 was more prone to yield losses than PR 115 because of higher weed biomass
production. In both years, 100% yield loss was observed where weeds were not controlled throughout
the season. In weed-free plots, the grain yield of PR 114 was 6.39-6.80 t ha-1, for PR 115, it was 6.49-
6.87 t ha-1. Gompertz and logistic equations fitted to yield data in response to increasing periods of
weed control and weed interference showed that, PR 114 had longer critical periods than PR 115.
Critical weed-free periods to achieve 95% of weed-free yield for PR 114 was longer than for PR 115
by 31 days in 2012 and 26 days in 2013. The identification of critical crop-weed competition periods
for different cultivars will facilitate improved decision-making regarding the timing of weed control
and the adoption of cultivars having high weed-suppressing abilities. Tillage and cover cropping have
been known to affect weed emergence for several ecological reasons. Most of the weed species
(Echinochloa crus-galli, Echinocloa colona, Eleusine indica, and Euphorbia hirta) under study
tended to populate the cover crop (CC) treatment more than the no-cover crop (no-CC) treatment.
Zero tillage (ZT) resulted in higher weed densities of most of the weed species studied. ZT system
resulted in a higher proportion of weed seeds in 0-2 cm of the soil layer at the time of crop sowing,
with 48-52% of broadleaved and 45-55% of grassy weed seeds; whereas, CONT had weed seeds
buried in deeper layers, with 47-48% of broadleaved and 50-55% of grassy weed seeds in the
lowermost layer (5-10 cm). The interaction effects of these treatments suggest that lesser herbicide
efficacy in ZT and CC plots led to higher weed pressure and weed biomass. Grain yield was
significantly higher in the conventional tillage system (2.40 - 3.32 t ha-1), because of lesser weed
pressure, than in ZT (2.08 - 2.73 t ha-1). Herbicide application (pendimethalin followed by bispyribacsodium)
alone, though significantly increasing DSR grain yield over that of the unsprayed check,
resulted in lesser grain yield compared with the weed-free check (5.07 - 5.12 t ha-1) by 14% and 27%
in 2012 and 2013, respectively. The information from this study will facilitate better decision making
in weed management through the integration of tillage systems and other weed control measures in
dry direct-seeded rice.
 
Date 2016-04-11T10:02:11Z
2016-04-11T10:02:11Z
2014
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/65417
 
Language en
 
Format application/pdf
 
Publisher PAU