Pre-emergence herbicides can tactically fit into conservation

agriculture systems and with various benefits

Vinay K Sindhu

Ph.D. student, Department of Agronomy

CCSHAU, Hisar

Integration ?

1. Surplus rice residue

2. Herbicide resistance in wheat

weeds

(7-10 t/ha)

1. Surplus rice residue

Surplus Rice residue- 43.5 million tonnes

Prohibited indiscriminate burning vide Notification No. 3/162/2006-STE(4)/946

dated 22.10.2013.

FIRs are being registered against farmers

Red dots depicting incidences of rice straw burning as captured by

NASA’s Suomi NPP satellite.

Nov 2, 2016

(http://earthobservatory.nasa.gov)

Conservation agriculture

1. Best/only possible solution

Direct drilling of wheat with Happy seeder

in surface mulched

Removal ×

OR

Incorporation×

2. Herbicide resistance

Rumex dentatus

Phalaris minorExplosion of HR in India

Status of Herbicide Resistance in India

S.

No.Weed Year Herbicide

1 Phalaris minor 1992 Isoproturon

Phalaris minor 1994 Diclofop

Phalaris minor 2002 Fenoxaprop

Phalaris minor 2007 Clodinafop

Phalaris minor 2010 Sulfosulfuron

Phalaris minor 2012 Pinoxaden

Phalaris minor 2013 Meso+iodosulfuron

2 Rumex dentatus 2013, 2016 MSM, SSN, Meso+iodo

3 Polypogon monspeliensis 2015 SSN, Meso+iodo, Halauxifen

4 Avena ludoviciana 2016 Clodinafop, FNP

5 Chenopodium album 2017 MSM, SSN, Meso+iodo

Courtesy – Dr. Samunder Singh

Village-

Nagla,

Fatehbad,

Haryana

(2015-16)

1 DAS- Stomp @ 2 l/ac

25 DAS- Sulfosulfuron

55 DAS- Pinoxaden

Total cost= Rs. 2100/acPrevious cost= Rs. 550

Cost of Herbicide Resistance

Single application of

Clodinafop/

sulfosulfuron at 35

DAS

Few years back Now

fb

fb

Continuous use of single group of herbicides

But we have many groups of herbicides in market

Herbicide rotation should be followed

It can buy you time but can not prevent HR

When resistance is of metabolic nature

Why we get resistance

Wheat

Sole reliance on POST herbicides in absence of any non-chemical

control measures

Why NOT resistance

51 weed species in rice have developed resistance.

Echinochloa crus-galli, a major rice weed -resistant to

10 different herbicide MoAs.

Butachlor resistance in China, Thailand and

Philippines

Rice

PRE herbicides + flooding till 15 DAT

Globally

India

No resistance against butachlor/pretilachlor

Why NOT resistance

66 weed species have developed resistance

against atrazine

Highest numbers of R weeds against any

herbicide

Maize

PRE herbicide + hand weeding/interculture

Globally

India

No resistance against atrazine till date

PRE herbicides/mixtures

2. Best/only possible solution

POST

+

Non-chemical tools

Zero-tillage

Crop competitiveness

Surface mulching

Wheat

Integration ?

Solution -2 Solution -1

How to use PRE

Herbicide resistance Surplus rice residue

PRE

herbicides

Residue

retention

Residues can intercept 15 to 80 % of PRE (Chauhan and Abugho, 2012)

CCS HAU, RSS, Karnal

ReferencesKumar et al 2013. Weed Technology 27:241–254

Chauhan and Albugo 2012. Weed Technology 26:627-632

Catherine et al 2013. Weed Technology 27:649–655

Dr. Samar Singh Dr. S S Punia Dr. Samunder Singh

Dr. Anil Duhan

Mulch and PRE herbicides interaction for proactive

management of HR weeds in wheat

Exp-I

Rice residue mulch x PRE herbicides (application rates on top of mulch)

Rice residue mulch levels PRE herbicides- 0 t/ha

- 6 t/ha

- 9 t/ha

- Pendimethalin 1.0 kg/ha

- Pendimethalin 2.0 kg/ha

- Metribuzin 0.140 kg/ha

- Metribuzin 0.280 kg/ha

- Untreated

Phalaris minor only (No wheat)

Seeding rate: 7.5 kg/ha

Line sowing at 30 cm row spacing

PRE on top of the mulch

Mulch

0 t/ha6 t/ha9 t/ha

0.0

50.0

100.0

150.0

200.0

250.0

300.0

350.0

400.0

0 t/ha 6 t/ha 9 t/ha

Fre

sh

bio

om

as

s (

g/s

q.m

)

Unsprayed

Pendi 1.0 kg/ha

Pendi 2.0 kg/ha

Metri 0.140 kg/ha

Metri 0.280 kg/ha

Fresh biomass of P minor (g/m2)

PRE herbicides when sprayed on top of the mulch, increase in

application rates didn’t improve weed control

Exp-II

Rice residue mulch x PRE herbicides (Below the mulch)

Rice residue mulch levels PRE herbicides- 0 t/ha

- 6 t/ha

- 12 t/ha

- Pendimethalin 0.75 kg/ha

Pendimethalin 1.0 kg/ha

- Pendimethalin 1.5 kg/ha

- Metribuzin 0.140 kg/ha

- Metribuzin 0.280 kg/ha

- Untreated

Phalaris minor only (No wheat)

Seeding rate: 7.5 kg/ha

Line sowing at 30 cm row spacing

PRE on soil surface

Mulching immediately

0.0

50.0

100.0

150.0

200.0

250.0

300.0

350.0

400.0

0 t/ha 6 t/ha 12 t/ha

Fre

sh

bio

mass (

g/s

q.

m)

Unsprayed Pendi 0.75 kg/ha

Pendi 1.0 kg/ha Pendi 2.0 kg/ha

Metri 0.140 kg/ha Metri 0.280 kg/ha

Fresh biomass of P minor

Alone application of 12 t/ha of mulch ------ + 11 % higher

Alone pendimethalin 1.0 kg/ha ---------- - 66 % lower

Pendi at 1.0 kg/ha + 12 t/ha ------- 100 % control

Under the mulch

0 t ha-1 6 t ha-1 12 t ha-1

Unsprayed

Pendi 0.75 kg ha-1

Pendi 1.0 kg ha-1

The proof in the plots

Mulch can reduce the herbicide dose

P minor sown in lines

Exp-III

Rice residue mulch + Seed rate + PRE herbicide mixtures in ZT wheat

Variety- HD 2967 , Spli-split

Rice residue

mulch levels

0 t/ha

4 t/ha

8 t/ha

Seed rates 100 kg/ha

125 kg/ha

PRE herbicides Pendimethalin 1.5 kg/ha + metribuzin 0.210 kg/ha

Pyroxasulfone 127.5 g/ha

Weed free

Weedy check

SprayingSowing with zero-drill

Mulching immediately

255

193

110

45

20

50

100

150

200

250

300

No mulch+noherbicide

Mulch 8t/ha+no

herbicide

Mulch 8t/ha+higher

seed rate+noherbicide

Nomulch+PRE

(pendi+metri)

Mulch 8t/ha+higherseed rate+

PRE(pendi+metri)

We

ed

de

ns

ity (

No

/sq

m)

Weed density at 65 DAS as influenced by integration of mulch, seed rate and PRE

herbicides mixture (pendimethalin 1.5 + metribuzin 0.210 kg/ha, beneath the mulch) in

ZT wheat.

Potential benefit of integrating non-chemical tactics with PRE herbicides

Exp-IV

Use of higher water volume or surface irrigation for penetrating PRE

herbicides in Happy seeder sown wheat

Spraying PRE with 1000 L/ha

Sowing with

TSR

Using as EPOST just before 1st

Irrigation

OR

Herbicide program Rates

(ai kg/ha)

Application timings % control

(P minor)

Pendi + metri 1.5 + 0.140 PRE with 1000 L/ha 91

Pendi + metri 1.5 + 0.140 20 DAS 97

Pyroxa + metri 0.1275 + 0.140 PRE with 1000 L/ha 95

Pyroxa + metri 0.1275+0.140 20 DAS 97

Weed-free - - 100

Unsprayed check - - -

Volume of water used for spray (PRE & 20 DAS): 1000 and 500 litres/ha

First irrigation : 21 DAS

Water volume and surface irrigation in Happy seeder sown wheat

Conclusions

Pre-emergence herbicides in wheat can be used in the presence of rice

residues by

1. Securing PRE herbicides under the mulch.

2. Applying PRE herbicides mixture with high carrier water volume (1000 L/ha)

3. Applying PRE herbicides mixture as early POST immediately before the 1st

irrigation (20 DAS)

ZT + 125 kg/ha seed rate + PRE herbicide mixtures, under the mulch + 8

t/ha mulch

Best package is