Effect of weed management in blackgram and its residual effect on succeeding mustard crop

R R UPASANIIRSA AGRICULTURAL UNIVERSITY

RANCHI-834006

PROBLEMS AND PROSPECTS OF WEED MANAGEMENT IN

BLACK GRAM Slow in Growth:

Less canopy:

luxurious growth of weeds:

Yield reduction up to 43.2-64.1 per cent (Rathi et al. 2004)

Manual weeding is tedious anduneconomical to practice:

Use of herbicides not onlyeconomical but also provides timelyprotection (Yadva et al.2015):

The herbicides should not leaveresidual effect in soil to affectsucceeding crop:

Herbicides should not be harmful to thesoil microflora:

Residual herbicide is needed to controlsecond flush of weeds emerging afterrains

Imazethapyr and its ready mixcombination with imazamox, newherbicides found promising to controlweeds in blackgram.

Keeping these in view, herbicides

imazethapyr alone or in combination

with imazamox and pendimethalin as

pre-mixture with imazethapyr were

tested under pre and post-emergence

conditions.

METHODOLOGYTreatments

1. imazethapyr 70 g/ha PE

2. imazethapyr 80 g/ha PE

3. imazethapyr 70 g/ha PoE

4. imazethapyr 80 g/ha PoE

5. imazethapyr 35% + imazamox 35% (Odyssey) 70 g/ha PE

6. imazethapyr 35% + imazamox 35%(Odyssey) 80 g/ha PE

7. imazethapyr 35% + imazamox 35%(Odyssey) 70 g/ha PoE

8. imazethapyr 35% + imazamox 35%(Odyssey) 80 g/ha PoE

9. pendimethalin.1000g/ha 1000 g/ha PE

10. imazethapyr 2%+ pendimethalin 30% (Valor) 10000 g/ha PE

11. hoeing twice

12. weedy check

Black gramvariety: T9Design: RBDReplication: 3D/S: 16th and 3rd July 2014 and 2015 D/H: 22nd and 12th September, 2014 and 2015

Succeeding mustard crop

• Variety: Shivani

• D/S: 29th October 2nd November, 2014 and 2015

• D/H: 10th and 28th February, 2015 and 2016

Major Weeds of Black gram

Amaranthus viridis Celosia argentea

Commelina benghalensisChloris barbata

Cyperus rotundus

Digitaria longiflora

Echinochloa sp

Stelaria media

Elusine indicaPanicum species

Panicum distichum Setaria glauca

RESULTS

Post emergence application of imazethapyr

+imazamox 80g/ha (Odyssey) reduced 77

and 43 % weed density and 41.03 & 40.47

% weed dry matter at 30 and 60 DAS

compared to mean weed density (451 &

295/m2) and weed dry matter (22.72 & 35.65

g/m2) of rest of the treatments.

WEED DENSITY and DRY MATTER

Post emergence ready mix of imazethapyr

and imazamox irrespective of doses showed

mean weed control efficiency of 88.14 and

86.39 percent respectively at 30 and 60 DAS

but showed slight phytotoxicity in black

gram plants at 15 days after application of

herbicides which mitigated after some time.

Weed Control Efficiency%

0

200

400

600

800

1000

1200

1400

1600

30 DAS

60 DAS

Weed density (no./m2)

0

20

40

60

80

100

120

140

160

30 DAS

60 DAS

Weed dry matter (g/m2)

0

10

20

30

40

50

60

70

80

90

100

30 DAS

60 DAS

Weed control efficiency %

Yield and economics:

Post emergence application of

imazethapyr + imazamox (Odyssey)

70g/ha similar to 80g/ha recorded

significantly higher seed (1.12 t/ha) and

straw yield (2.33t/ha), net return (Rs.

24,126/-) and B:C ratio (2.31).

1.12

0

0.5

1

1.5

2

2.5

3

3.5

Seed yield(t/ha)

Straw yield (t/ha)

Effect on Succeeding Crop

Pre or post emergence applicationof imazethapyr alone or incombination with imazomox as wellas with pendimethalin 70 or 80 g/haapplied in black gram did not affectmustard yield.

Treatments Siliqua/Pla

nt

1000 seeds

weight

branche

s/plant

plant

s/m2

Yield (t/ha)

Seed Straw

imazethapyr. 70g/ha PRE 83 3.83 5 36 1.07 2.88

imazethapyr 80g/ha PRE 94 3.70 8 36 1.08 2.82

imazethapyr 70g/ha POE 88 3.83 5 38 1.10 2.80

imazethapyr 80g/ha POE 114 3.76 7 32 0.96 2.69

imazethapyr + imazamox70g/ha PRE 101 3.72 6

37

1.09 3.10

imazethapyr + imazamox 80g/ha PRE 63 3.72 4

38

1.26 3.54

imazethapyr + imazamox 70g/ha POE 79 3.74 5

32

1.21 3.01

imazethapyr + imazamox 80g/ha POE 107 3.74 7

36

1.11 2.91

pendimethalin.1000g/ha PRE 92 3.87 6 30 0.92 2.64

imazethapyr + pendimethalin 1000g/ha 102 3.52 7

37

1.25 3.38

hoeing twice 102 3.93 6 37 1.23 3.48

weedy check 65 3.91 4 32 0.85 2.62

LSD (P=0.05)

NS NS NS 2.80 0.40 1.22

Weed control methods in black gram and its effect on yield attributing character and yield of mustard

CONCLUSION

Post emergence application of imazethapyr 35% +

imazamox 35% 70g/ha recorded maximum seed

(1.12 t/ha) and straw yield (2.33 t/ha), net return

(Rs. 24,126/-) and B:C ratio (2.31) without affecting

succeeding mustard yield (1.21 t/ha).

References:1.Rathi JPS, Tewari AN and Kumar M. 2004. Integrated weedmanagement in blackgram (Vigna mungo L.).Indian Journal of Weed Science 36 : 218- 220.

2. K.S. Yadav, J.P. Dixit and B.L. Prajapati. 2015.Weed management effects on yield and economics of blackgram. Indian Journal of Weed Science 4 (2): 136 –138 , 2015