WEED MANAGEMENT WITH NEW GENERATION HERBICIDES IN MAIZE (Zea mays L.) AND THEIR RESIDUAL EFFECT ON SUCCEEDING GREENGRAM IN ALFISOLS
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Date
2021-11-22
Authors
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Journal ISSN
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Publisher
Acharya N.G. Ranga Agricultural University, Guntur
Abstract
A field experiment entitled “Weed management with new generation
herbicides in maize (Zea mays L.) and their residual effect on succeeding
greengram in Alfisols” was conducted at S.V. Agricultural College Farm, Tirupati
campus of Acharya N.G. Ranga Agricultural University, Andhra Pradesh during
rabi, 2017-18 and 2018-19 and summer 2018 and 2019. The treatments consisted of
atrazine @ 1.0 kg a.i. ha-1 as pre emergence fb one HW at 30 DAS (T1), atrazine @
1.0 kg a.i. ha-1 as pre emergence fb tembotrione @ 120 g a.i. ha-1 as post emergence
(T2), atrazine @ 1.0 kg a.i ha-1 as pre emergence fb topramezone @ 30 g a.i. ha-1 as
post emergence (T3), atrazine @ 1.0 kg a.i. ha-1 as pre emergence fb halosulfuron
methyl @ 67.5 g a.i. ha-1 as post emergence (T4), atrazine @ 1.0 kg a.i. ha-1 as pre
emergence fb 2,4-D amine salt @ 580 g a.i. ha-1 as post emergence (T5), atrazine @
1.0 kg a.i. ha-1 as pre emergence fb tembotrione @ 60 g + 2,4-D amine salt @ 290 g
a.i. ha-1 as post emergence (T6), atrazine @ 1.0 kg a.i. ha-1 as pre emergence fb
topramezone @ 15 g + 2,4-D amine salt @ 290 g a.i. ha-1 as post emergence (T7),
atrazine @ 1.0 kg a.i. ha-1 as pre emergence fb halosulfuron methyl @ 34 g + 2,4-D
amine salt @ 290 g a.i. ha-1 as post emergence (T8), hand weeding twice at 15 and
30 DAS (T9) and weedy check (T10). The experiment was laidout in a randomized
block design with three replications. Maize hybrid DHM-117 and greengram variety
IPM-2-14 were used in the present study.
The predominant weed species noticed in the experimental field were
Brachiaria ramosa, Cyperus rotundus, Boerhavia erecta, Cleome viscosa,
Phyllanthus niruri, Trichodesma indicum and Borreria hispida.
The total weed density and dry weight which includes grasses, sedges, broad
leaved weeds as well as total weeds were lower with hand weeding twice at 15 and
30 DAS (T9), which was however, comparable with atrazine 1.0 kg ha-1 as pre
emergence fb topramezone 30 g ha-1 as post emergence (T3), atrazine 1.0 kg ha-1 as
pre emergence fb tembotrione 120 g ha-1 as post emergence (T2) and atrazine 1.0 kg
ha-1 as pre emergence fb one HW at 30 DAS (T1), without any significant disparity
among them. The total weed density and dry weight were significantly higher with
weedy check at all the growth stages of maize, during both the years of study.
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Higher weed control efficiency and lower weed index were recorded with
hand weeding twice at 15 and 30 DAS (T9), which was however at par with atrazine
1.0 kg ha-1 as pre emergence fb topramezone 30 g ha-1 as post emergence(T3),
atrazine 1.0 kg ha-1 as pre emergence fb tembotrione 120 g ha-1 as post emergence
(T2) and atrazine 1.0 kg ha-1 as pre emergence fb one HW at 30 DAS (T1) during the
two years of study. Highest weed index was noticed with weedy check (T10).
Among the different weed management practices evaluated, growth
parameters of maize viz., plant height, leaf area index and dry matter production
were higher with hand weeding twice at 15 and 30 DAS (T9), which was however, at
par with application of atrazine1.0 kg ha-1 as pre emergence fb topramezone 30 g ha-
1 as post emergence (T3), atrazine 1.0 kg ha-1 as pre emergence fb tembotrione 120 g
ha-1 as post emergence (T2) and atrazine 1.0 kg ha-1 as pre emergence fb one HW at
30 DAS (T1), in the order of descent during both the years of study, while these were
significantly lowest with weedy check (T10).
SPAD chlorophyll meter reading was higher with hand weeding twice at 15
and 30 DAS (T9), followed by atrazine 1.0 kg ha-1 as pre emergence fb topramezone
30 g ha-1 as post emergence (T3), atrazine 1.0 kg ha-1 as pre emergence fb
tembotrione 120 g ha-1 as post emergence (T2) and atrazine 1.0 kg ha-1 as pre
emergence fb one HW at 30 DAS (T1), in the order of descent without any
significant disparity among themselves, during both the years of experimentation.
Yield attributes, kernel and stover yields and harvest index of maize were
higher with hand weeding twice at 15 and 30 DAS (T9), which was in parity with
application of atrazine 1.0 kg ha-1 as pre emergence fb topramezone 30 g ha-1 as post
emergence (T3), atrazine 1.0 kg ha-1 as pre emergence fb tembotrione 120 g ha-1 as
post emergence (T2) and atrazine 1.0 kg ha-1 as pre emergence fb one HW at 30 DAS
(T1). Significantly lowest yield attributes and yield of maize were recorded with
weedy check (T10) during both the years of study.
Higher nutrient uptake by maize and lower nutrient uptake by weeds was
observed with hand weeding twice at 15 and 30 DAS (T9), which was at par, with
application of atrazine 1.0 kg ha-1 as pre emergence fb topramezone 30 g ha-1 as post
emergence (T3), atrazine 1.0 kg ha-1 as pre emergence fb tembotrione 120 g ha-1 as
post emergence (T2) and atrazine 1.0 kg ha-1 as pre emergence fb one HW at 30 DAS
(T1), whereas, weedy check (T10) recorded significantly lowest nutrient uptake by
maize and highest nutrient uptake by weeds, during both the years of
experimentation.
Higher gross returns of maize were realized with hand weeding twice at 15
and 30 DAS (T9), which was at par with atrazine 1.0 kg ha-1 as pre emergence fb
topramezone 30 g ha-1 as post emergence (T3), atrazine 1.0 kg ha-1 as pre emergence
fb tembotrione 120 g ha-1 as post emergence (T2) and atrazine 1.0 kg ha-1 as pre
emergence fb one HW at 30 DAS (T1), in the order of descent.
Higher net returns of maize were realized with atrazine 1.0 kg ha-1 as pre
emergence fb topramezone 30 g ha-1 as post emergence (T3), atrazine 1.0 kg ha-1 as
pre emergence fb tembotrione 120 g ha-1 as post emergence (T2), hand weeding
twice at 15 and 30 DAS (T9) and atrazine 1.0 kg ha-1 as pre emergence fb one HW at
30 DAS (T1) in the order of descent, without significant disparity among them,
during both the years of study. Higher benefit cost ratio was noticed with atrazine
1.0 kg ha-1 as pre emergence fb topramezone 30 g ha-1 as post emergence (T3), which
was at par with atrazine 1.0 kg ha-1 as pre emergence fb tembotrione 120 g ha-1 as
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post emergence (T2), during both the years of study. Lowest gross returns, net
returns and benefit cost ratio were realized with weedy check.
Germination percentage of succeeding greengram crop was not affected due
to different weed management practices imposed in maize. Phytotoxicity was not
observed on succeeding greengram crop due to pre and post emergence herbicides
applied in maize, during both the instances of study.
Lower weed density, biomass and higher growth parameters, yield attributes,
seed and haulm yields of greengram were observed with hand weeding twice at 15
and 30 DAS (T9), which was however, comparable with atrazine 1.0 kg ha-1 as pre
emergence fb one HW at 30 DAS (T1), atrazine 1.0 kg ha-1 as pre emergence fb
topramezone 30 g ha-1 as post emergence (T3), atrazine 1.0 kg ha-1 as pre emergence
fb tembotrione 120 g ha-1 as post emergence (T2) and atrazine 1.0 kg ha-1 as pre
emergence fb halosulfuron methyl 67.5 g ha-1 as post emergence (T4) in the order of
descent, due to the residual effect of weed management practices tried in preceding
maize, during both the instances of study.
Enzyme activity viz., soil phosphatases, urease and dehydrogenase and total
microbial population at harvest of maize were statistically comparable in the weed
management practices i.e. T2, T3, T4, T5, T6, T7 and T8 and were significantly higher
than atrazine 1.0 kg ha-1 as pre emergence fb one HW at 30 DAS (T1), hand weeding
twice at 15 and 30 DAS (T9) and weedy check (T10), which inturn were at par among
themselves, during both the years of experimentation.
In succeeding greengram, enzyme activity viz., acid phosphatase, alkaline
phosphatase, urease and dehydrogenase and the total microbial population in soil
which includes bacteria, fungi and actinomycetes was not statistically altered from
sowing to harvest, due to weed management practices imposed in preceding maize.
Herbicide residues were not detected in the soil at harvest of maize with pre
emergence application of atrazine 1.0 kg ha-1 or with 2,4-D amine salt 580 g ha-1 as
post emergence. Residues of tembotrione 120 or 60 g ha-1, topramezone 30 or 15 g
ha-1 and halosulfuron methyl 67.5 or 34 g ha-1 as post emergence application were
detected in the soil, but the amount of residues were not sufficient enough to cause
any phytotoxic effect on succeeding greengram. Herbicide residues were not
detected in the soil at 20, 40 DAS and at harvest of succeeding greengram.
Net returns and benefit cost ratio of succeeding greengram were higher with
hand weeding twice at 15 and 30 DAS (T9), which was closely followed, by atrazine
1.0 kg ha-1 as pre emergence fb one HW at 30 DAS (T1), atrazine 1.0 kg ha-1 as pre
emergence fb topramezone 30 g ha-1 as post emergence (T3), atrazine 1.0 kg ha-1 as
pre emergence fb tembotrione 120 g ha-1 as post emergence (T2) and atrazine 1.0 kg
ha-1 as pre emergence fb halosulfuron methyl 67.5 g ha-1 as post emergence (T4), in
the order of descent during both the years of investigation.
Based on the results obtained in the present investigation, it can be concluded
that atrazine 1.0 kg ha-1 as pre emergence fb topramezone 30 g ha-1 or tembotrione
120 g ha-1 as post emergence were considered to be the most effective and
economical weed management practices to increase the productivity and to
maximize the net returns in rabi maize at times of labour shortage and without any
residual effect on succeeding greengram and resulted in higher seed yield and net
returns of greengram.
Description
WEED MANAGEMENT WITH NEW
GENERATION HERBICIDES IN MAIZE (Zea
mays L.) AND THEIR RESIDUAL EFFECT ON
SUCCEEDING GREENGRAM IN ALFISOLS