Response of Indian Mustard [Brassica juncea (L.) Czern and Coss.] to Weed Management and Nitrogen Application
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Date
2015
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MPUAT, Udaipur
Abstract
A field experiment entitled “Response of Indian Mustard [Brassica juncea
(L.) Czern and Coss.] to Weed Management and Nitrogen Application” was
conducted on clay loam soils, at Instructional Farm of Rajasthan College of
Agriculture, Udaipur during rabi, 2014-2015.
The experiment comprising 15 treatment combinations consisted of 5 weed
management practices (pendimethalin 0.75 kg ha-1 as pre emergence, oxadiargyl 0.09
kg ha-1 as pre emergence, quizalofop-ethyl 0.05 kg ha-1 25 DAS, hand weeding 25
DAS and weedy check) and 3 nitrogen levels ( 45, 60 and 75 kg ha-1). These treatment
combinations were evaluated under factorial randomized block design with three
replications. The variety BIO-902 (Pusa Jaikisan) was used for this purpose.
The results of experiment reveal that all weed management practices markedly
reduced crop-weed competition compared to weedy check. The results further revealed
that among all herbicidal treatments pre-emergence application of oxadiargyl 0.09 kg
ha-1 significantly lowered density and dry matter of monocot, dicot and total weeds
throughout crop growth period as compared to weedy check which was statistically at
par with one hand weeding done at 25 DAS in reducing dry matter of all categories of
weeds. Total weed density and their dry matter under oxadiargyl 0.09 kg ha-1 was 5.18
m-2 and 72.94 kg ha-1 at 30 DAS; 7.99 m-2 and 141.59 kg ha-1 at 60 DAS; 9.50 m-2 and
217.54 kg ha-1 at 90 DAS, respectively; thus, reduced total weed dry matter by this
treatment to the tune of 75.81, 74.24 and 67.11 per cent, respectively compared to
weedy check. Weed control efficiency of total weeds at 30, 60 and 90 DAS under
oxadiargyl 0.09 kg ha-1 (75.83, 74.11 and 67.01 per cent, respectively) was comparable
to one hand weeding with corresponding values as 79.55, 76.35, 69.50 per cent. On the
contrary, minimum total weed control efficiency at these stages were recorded under quizalofop-ethyl 0.05 kg ha-1 (23.92, 20.69 and 19.71 per cent, respectively) with
negligible dicot weed control among all the weed management treatments. Uptake of
N and P by weeds at 90 DAS was found significantly lower in all the weed
management treatments compared to weedy check. Oxadiargyl 0.09 kg ha-1 recorded
the least uptake of N (4.37 kg ha-1) and P (0.790 kg ha-1) by total weeds next to one
hand weeding treatment with very close difference of 0.35 and 0.48 kg ha-1,
respectively. The per cent reduction in N and P uptake by total weeds with one hand
weeding was 70.31 and 69.64, respectively whereas, the respective per cent reduction
in uptake of these nutrients with oxadiargyl 0.09 kg ha-1 was 67.73 and 67.68
compared to weedy check.
Compared to weedy check, all the weed management treatments tended to
significantly increased dry matter accumulation and primary as well as secondary
branches plant-1 at harvest and leaf area index at 30, 60 and 90 DAS in Indian mustard.
As far as height of the plant is concerned, it is observed that in all weed management
treatments except pendimethalin it was found statistically at par and was significantly
reduced under this treatment compared to rest of the treatments including weedy
check. This treatment also showed phytotoxicity in terms of stunting effect on plant.
Dry matter accumulation, primary and secondary branches plant-1 at harvest and leaf
area index at 30, 60 and 90 DAS recorded under oxadiargyl 0.09 kg ha-1 as 56.24 g
plant-1, 6.17, 17.30, 2.47, 4.43 and 3.80, respectively while in one hand weeding the
respective values of these parameters were 56.60 g plant-1, 6.78, 18.17, 2.40, 4.44 and
3.89 and these parameters were found statistically at par under these two treatments.
Similarly, both these treatments recorded significantly higher number of siliquae
plant-1 and weight of 1000 seed as compared to weedy check and were statistically at
par to each other in this regard. The uptake of total nitrogen and phosphorus by the
crop was more in one hand weeding compared to pre-emergence application of
oxadiargyl 0.09 kg ha-1 (118.33 and 25.35 kg ha-1, respectively) by 2.08 and 0.34 kg
ha-1 and the minimum being recorded under weedy check with the respective values as
74.12 and 16.06 kg ha-1.
Maximum seed yield (2240 kg ha-1) was recorded under one hand weeding,
however; it was statistically at par with pre-emergence application of oxadiargyl 0.09
kg ha-1 (2234 kg ha-1). In a similar way, stover and biological yields (5589 and 7830
kg ha-1, respectively) were also recorded maximum under one hand weeding treatment
which was very closely followed by oxadiargyl 0.09 kg ha-1. However, maximum harvest index (29.03 per cent) was registered under oxadiargyl 0.09 kg ha-1 which was
found statistically at par with one hand weeding 25 DAS and pendimethalin 0.75 kg
ha-1 treatments in this regard. The per cent enhancement in seed yield under hand
weeding and oxadiargyl 0.09 kg ha-1 was 70.73 and 70.27, respectively compared to
weedy check. Among different herbicidal treatments, oxadiargyl 0.09 kg ha-1 recorded
the highest oil yield (899 kg ha-1) comparable to one hand weeding 25 DAS (908 kg
ha-1).
As far as net returns and benefit cost ratio is concerned these were recorded
maximum under oxadiargyl 0.09 kg ha-1 with the values of ` 67136 ha-1 and 3.05,
respectively closely followed by one hand weeding with the respective values as
` 65757 ha-1 and 2.76.
Nitrogen levels had no significant influence on weed density at all stages of
crop growth. Application of 60 and 75 kg N ha-1 significantly raised total weed dry
matter at 30 and 60 DAS compared to 45 kg N ha-1, while at 90 DAS only 75 kg N ha-1
recorded significantly higher total weed dry matter compared to the lowest level.
Nitrogen and phosphorus content as well as uptake by weeds were significantly
increased up to 75 kg N ha-1 as compared to respective lower level.
Plant height, LAI, primary and secondary branches were significantly
increased by 75 kg N ha-1 compared to 45 kg N ha-1. Application of 60 kg N ha-1
recorded 5.58, 26.10, 36.53 and 51.74 g dry matter plant-1 at 30, 60, 90 DAS and at
harvest, respectively while, the respective values of this parameter at these stages of
observations under 75 kg N ha-1 was 5.93, 30.62, 41.81 and 58.14 g dry matter plant-1.
Both these N levels were found to increase the days to maturity significantly as
compared to corresponding lower levels. Moreover, a significant increase in N and P
content as well as their uptake by seed and stover were observed with 75 kg N ha-1
compared to lower levels. Application of 60 and 75 kg N ha-1 significantly increased
chlorophyll content of leaves as compared to the lowest level of nitrogen.
As compared to 45 and 60 kg N ha-1, the yield attributes viz. siliquae plant-1
and weight of 1000 seed were significantly increased due to application of 75 kg N
ha-1 by 19.71, 8.56 and 4.87, 3.13 per cent, respectively. Significantly superior seed
yield was obtained under 60 and 75 kg N ha-1 with corresponding per cent increase of
17.20 and 29.13 as compared to 45 kg N ha-1. Likewise, application of 60 and 75 kg N
ha-1 was also found superior to 45 kg N ha-1 with regard to enhancing oil, stover and
biological yields of Indian mustard. Oil, stover and biological yields of the crop were
increased by 19.94, 13.66, 14.63 and 33.53, 22.92, 24.60 per cent owing to application
of 60 and 75 kg N ha-1, respectively compared to 45 kg N ha-1.
The highest net returns (` 61333 ha-1) and B-C ratio (2.75) were obtained
under application of 75 kg N ha-1, whereas the minimum values for these economic
parameters were recorded under application of 45 kg ha-1 (` 43263 ha-1 and 1.97,
respectively).
Description
Response of Indian Mustard [Brassica juncea (L.) Czern and Coss.]
to Weed Management and Nitrogen Application”
Keywords
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Citation
Kalita and Mundra, 2015