WEED AND NUTRIENT MANAGEMENT IN DRY DIRECT SOWN RICE IN NORTHCOASTAL ANDHRA PRADESH
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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 and nutrient management in dry
direct sown rice in North-Coastal Andhra Pradesh” was conducted on
sandy clay loam soils of Agricultural College Farm, Naira during kharif, 2018
and 2019. The design adopted was split-split plot with three replications. The
treatments consisted of four weed control methods assigned to main plots,
viz., W1: Unweeded check, W2: Hand weeding twice at 20 and 40 DAS, W3:
Pyrazosulfuron ethyl @ 20 g a.i ha-1 at 8-12 DAS fb.florpyrauxifen-benzyl @
31.25 g a.i ha-1 at 25 DAS and W4: Bispyribac sodium @ 150 g a.i ha-1 at 20
DAS fb. 2,4-D amine salt @ 600 g a.i ha-1 + fenoxyprop-ethyl with safener @
150 g a.i ha-1 at 40-45 DAS, four nutrient management practices assigned to
sub plots, viz., N1: Foliar application of 19-19-19 @ 1% at 20 DAS and 2% at
40 DAS fb.75% RDF from conversion onwards in three splits, N2: Foliar
application of 19-19-19 @ 1% at 20 DAS and KNO3 @ 2% at 40 DAS fb.75%
RDF from conversion onwards in three splits, N3: 100% RDF (Entire P
through SSP, ⅓rd N and ½ K as basal and remaining N and K through top
dressing as per recommendation) and N4 : Farmer’s practice and three
micronutrient management practices assigned to sub-sub plots viz., M1: ZnSO4
@ 50 kg ha-1, M2: Foliar application of ZnSO4 @ 0.2% twice at 20 and 40
DAS andM3: Foliar application of ZnSO4 @ 0.2% and FeSO4 @ 0.5% each at
20 and 40 DAS.
The important weed flora observed in the experimental site consisted of
eleven species belong to seven different families. The species observed were
Echinochloa colona (L.) Link., Echinochloa crus-galli (L.) Link., Cynodon
dactylon (L.) Pers., Cyperus rotundus L., Cyperus difformis L., Fimbristylis
miliaceae (L.) Vahl., Eclipta alba (L.) Hassk, Ludwigia parviflora L.,
Ammania baccifera L., Euphorbia hirta L. and Trianthema portulacastrum L.
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All the three groups of weeds were effectively suppressed at all
sampling intervals due to sequential application of herbicides (W3 and W4)
during both the years. W3 resulted in significant decline in the total weed
density and weed drymatter while, it was the highest with unweeded check.
Maximum density of total weeds and weed drymatter were noticed in plots
which received 100% RDF at all intervals of sampling.Total weed density and
weed drymatter observed in M3 was significantly lower which was
comparable with M2. While, it was maximum with M1 at all sampling
intervals.
Significantly taller plants, tiller number hill-1, leaf area, drymatter
production, SPAD meter readings were observed with W3 comparable with
W4 and with N3 which was found on par with N1 and N2 and found
significantly superior to N4. At all stages of sampling significantly maximum
growth stature was associated with M1. While, it was minimum with M3.
Maximum number of yield attributes and grain and straw yield were
found with W3 which was comparable with W4 and N3 which was however,
comparable with N1 and N2. M1 recorded significantly higher number of yield
attributes and yield.
Significantly higher uptake of nitrogen, phosphorus and potassium at
tillering as well as by grain and straw was noticed with W3 and N3, while,
potassium uptake values were higher with N1 which were on par with N2 and
N3. The uptake of these nutrients by rice at tillering as well as by grain and
straw was found to be the lowest with N4. Application of M1 found higher
uptake values which was however, on par with M2. Significantly lower values
of uptake were registered with M3.
Uptake of zinc and iron at tillering as well as by grain and straw of rice
was significantly higher with W3 which was however, comparable with W4.
While, it was found to be minimum with W1. The differences in the uptake of
zinc and iron among N3, N2 and N1 were comparable with each other and
significantly superior to N4. Higher quantity of zinc and iron uptake was
found with M1 except with uptake of iron by grain where, M3 registered
significantly higher values. While, the uptake values for zinc and iron were
minimum with M3.
Post-harvest soil available nitrogen, phosphorus and potassium were
found to be significantly higher with W1 while, the differences between W3
and W2 were found to be on par with each other. Significantly lower values
were associated with W3. Significantly higher post harvest soil available
nitrogen, phosphorus and potassium were found with N4, N1 and N2
respectively. While, lower values for post harvest soil available nutrients were
found with N3. Large amount of post harvest soil available nitrogen,
phosphorus and potassium were noticed with M3.
The higher values for post harvest soil available zinc and iron were
registered with W1. While, they were at their lowest with W3 and N4 recorded
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higher values which was however, comparable with N1. Significantly lower
values were observed with N3.Significantly large values for post harvest soil
available zinc was noticed with M1 while, it was the lowest with M3. Whereas,
M3 registered significantly higher values for post harvest soil available iron
while, it was minimum with M2.
Significantly higher gross returns, net returns and B:C ratio were
realized with W3 and while they were minimum with W1. Maximum returns
and B:C ratio associated with N3 was found on par with N2 and N1. The gross
and net returns obtained with M1 and M2 were found comparable with each
other and significantly superior to M3. Higher B:C ratio was associated with
M1 and found superior to rest of the treatments. While, the B:C ratio values
associated with M2 and M3 are comparable with each other and significantly
lower than M1.
From the present investigation, it could be concluded that sequential
application of pyrazosulfuron ethyl @ 20 g a.i ha-1 at 8-12 DAS
fb.florpyrauxifen-benzyl @ 31.25 g a.i ha-1 at 25 DAS along with application
of 100% RDF and basal application of ZnSO4 @ 50 kg ha-1 were found to be
highly effective and economical package for successful cultivation of dry
direct sown rice in North-Coastal A.P.
Description
WEED AND NUTRIENT MANAGEMENT IN
DRY DIRECT SOWN RICE IN NORTHCOASTAL
ANDHRA PRADESH