Weed Science Section

Section I/c Dr. Anil Dixit, Principal Scientist

Major Research Achievements:

Application of N, P and K at recommended dose in rice and wheat improved the growth

and yield attributes in both the crops. These led to better solar radiation interception and

least transmission to the ground, which helped in reduction of weed emergence and less

competition offered by weeds to the crop for various resources. Therefore, the highest

grain yield of rice and wheat were harvested.

Nitrogen has better response towards growth and development of crop followed by P and

least effect of K. These mainly because of higher exchangeable K stock present in the

soil, which are readily available to the plants.

Application of 125% of recommended dose of nitrogen was comparable to 100% of N,

but, still 125% had edge over 100% N in growth and development of rice and wheat.

Higher regimes of nitrogen favoured the crop growth, resulted lower solar radiation

transmission. These leads to poor emergence of weeds, thus, lowered weed density and

dry biomass was recorded.

Incorporation of Sesbania before rice transplanting had positive response on growth,

development and yield of rice and also to the weed suppression ability. Sesbania

incorporated plots had also reduced the 27.5% direct use of fertilizer and improvised the

grain yield by 20.3% over without Sesbania. Though the effect of Sesbania on wheat was

not promising but was significantly superior in rice.

Sulfosulfuron 75% + Metsulfuron m e t h y l 5 % W G , a r e a d y m i x formulation

was demonstrated and the chemistry had significantly increased the growth and yield

attributing characters of wheat, resulted in higher grain yield. The formulation had the

weed control efficiency of 78-88%, which curtailed competition among weed and wheat

plants. Application of this formulation provided yield increment of 56.4% over the hand

weeding practice followed by farmers.

Pretilachlor(6%) + Pyrazosulfuron(0.15%) GR (600+15 g/ha) and weedy check was

tested in farmers’ field along with farmers practice at Dhamtari, Bilaspur and Raipur

districts of Chhattisgarh. Pretilachlor 6% + Pyrazosulfuron 0.15% was applied 5-7 days

after transplanting for evaluating this molecule at farmers’field. The study sites were

predominantly dominated with Cyperusrotundus,C.difformis,Echinochloacolona,

E.crusgalli, Cynadondactylon, Ischaemomrogusum, Commelina sp., Amaranthus sp.,

Alternenthrasessilis, Monochoria sp., Marsiliaquadrifoliaand Ludwigiaparviflora. It was

recorded that weed control efficiency was about 80-91% and there was yield

improvement of 40-50%, irrespective of locations and varieties.

Farmer’s Feedback: Farmer’s reaction was positive towards the technology assessed. They are

easily adopted the technology due to effective control of weeds by using Pretilachlor 6% +

Pyrazosulfuron 0.15% GR on their field. Highest average net returns (Rs 58,650/ha) recorded

with the application of Pretilachlor 6% + Pyrazosulfuron 0.15% GR.

Weed mangement in DSR

Priming of seeds with calcium chloride (osmo-priming, 150 µmol) reduced weed biomass

resulted improved rice grain yield by 41% over non-primed seeds. Moderately weeded

plots significantly suppressed the weeds and improved the rice grain yield by 1.24 times

over weedy check.

Adoption of narrow row spacing of 15 cm significantly suppressed the weed biomass and

increased the weed suppression efficiency and harvested higher grain yield over wider

spacing (25 cm).

Adoption of seed rate from 60- 100 kg/ha gave insignificant yield advantage, however,

Seeds rate of 100 kg/ha reduced the weed biomass, and reduction in seed rate

significantly increases the weed dry biomass.

As per the severity of weeds, appropriate weed management practice need to be followed.

Pre-emergence and early post emergence herbicides need to be adopted to avoid the

competition during early stage of the crop.

L

List of the technology developed from ICAR-National Institute of Biotic Stress

Management, Baronda, Raipur (CG)

1. Weed management in transplanted rice

Sl. No. Particulars Details

1. Technology Weed management through premix molecules of herbicide in

transplanted rice

2. Developed by Dr. Anil Dixit and Dr. V.K. Choudhary, ICAR-NIBSM,Raipur

3. Year of

development/

validation

2013-17

4. Rational Rice is an important cereal crop of India, this has been producing

in an area of 143 m ha with the production of 100 m t. Weeds are

major biological constraints which causes severe yield reduction

up to 90% mostly depended on crop establishment method and

ecosystem. One or two hand weeding is being followed in rice to

minimize the weed problem, but, it requires lots of labour to

complete the operation on time. Scanty availability of labour

during peak time and high wages became non-profitable and un-

economical. Thus cost effective and effective weed control was

need of the hours. Rice fields are infested with wide range of

weeds. In order to minimize the infestation level of weeds different

herbicides were tested and narrow down the list of herbicides. The

performance of herbicides was tested continuously for three years.

The hypothesis was that pretilachlor will take care of grassy weeds

and pyrazosulfuron ensure to minimize the density of broadleaved

weeds and sedges. Our findings suggested that premix application

of pretilachlore (6%) + pyrazosulfuron (0.15% GR) at 615 g/ha at

6-8 days after transplanting with the help of appropriate carrier

(e.g. sand) with thin water layer during early stages gives wider

weed control.

Apply pyrazosulfuron 10 WP @ 25 g/ha within 3 days after

transplanting with 25 kg sand/ha followed by Bispyribac sodium

10 SC @ 25 g/ha at 20 days after transplanting and maintained

water layer 3 days after application

5. Impact of

technology

Premix application of pretilachlore (6%) + pyrazosulfuron (0.15%

GR) at 615 g/ha at 6-8 days after transplanting gave 77% of weed

control. These controlled wide range of weeds (broadleaved

weeds, sedges and up to some extent grasses). Presence of thin

layer of water during early stages of crop enhanced the efficacy of

herbicides, and it has some phyto-tonic effect on crop which

helped in development of better yield attributes owing to this

harvested 39% higher rice grain yield over weedy plot.

Economical comparison was made and it was found that

pretilachlore (6%) + pyrazosulfuron (0.15% GR) at 615 g/ha

recorded 2.05 of benefit to cost ratio.

Weed control efficiency 76% over control with yield improvement

90% over weedy check. It was noticed that these technology has

yield reduction of 8.5% than two hand weeding but there was

saving of Rs 6000/ha over two hand weeding.

6. Field plates

Control

2. Weed management in transplanted/Direct seeded rice

Particulars Details

1 Technology Pyrazosulfuron 10 WP followed by Bispyribac sodium 10 SC against

partial weeding in rice

2 Developed by Dr. Anil Dixit and Dr. V.K. Choudhary, ICAR-NIBSM,Raipur

3 Year of

development/val

idation

2013-17

4 Rational Rice is an important cereal crop of India, this has been producing in an

area of 143 m ha with the production of 100 m t. Weeds are the major

constraint in DSR production systems. DSR improves water use

efficiency, and its widespread adaptation has eliminated time and

edaphic conflicts in wheat-rice cropping systems in India, DSR is

vulnerable to weed competition, and timely weed management is

indispensable. In DSR, weeds emerge simultaneously with rice

seedlings and compete with rice plants at an early growth stage, when

rice is particularly susceptible to competition. Thus cost effective and

effective weed control was need of the hours. Rice fields are infested

with wide range of weeds. In order to minimize the infestation level of

weeds different herbicides were tested and narrow down the list of

herbicides. The performance of herbicides was tested continuously for

three years. The hypothesis was that Pyrazosulfuron 10 WP followed

by Bispyribac sodium 10 SC against partial weeding in rice Apply

pyrazosulfuron 10 WP @ 25 g/ha within 3 days after transplanting

with 25 kg sand/ha maintained water layer 3 days after application

followed by Bispyribac sodium 10 SC @ 25-30 g/ha at 20 days after

transplanting or direct seeding.

5 Impact of

technology

Apply pyrazosulfuron 10 WP @ 25 g/ha within 3 days after

transplanting with 25 kg sand/ha followed by Bispyribac sodium 10

SC @ 25 g/ha at 20 days after transplanting and maintained water

layer 3 days after application. Weed control efficiency 76% over

control with yield improvement 90% over weedy check. It was noticed

that these technology has yield reduction of 8.5% than two hand

weeding but there was saving of Rs 6000/ha over two hand weeding.

6 Field plates

Control

3. Sustainable cultural weed management in transplanted rice

S.No Particulars Details

1. Technology Sustainable cultural weed management with green manuring

in transplanted rice

2. Developed by Dr. V.K. Choudhary and Dr. Anil Dixit ICAR-

NIBSM,Raipur

3. Year of

development/validati

on

2014-16

4. Rational Green manuring (Sesbania, sunhemp etc.) is an important

eco-friendly and effective technology for optimizing the

agricultural production system ensuring sustainable

productivity without any environmental problem. The

importance of green manuring entrusted for field

experimentation at ICAR-National Institute of Biotic Stress

Management Raipur (CG) during pre monsoon season of

2014, 2015 and 2016 to assess the performance of green

manuring (Sesbania aculata) on rice (Oryza sativa).

Sesbania aged 32-35 days were incorporated in the field with

the help of rotavator, and rice seedlings were transplanted

five days after incorporations. Sesbania incorporated plots

were compared with normal plots where recommended dose

of fertilizer was applied. It was hypothesized that

incorporation of sesbania not only give better crop yield and

curtail the nutrient requirement but also suppress the weed

emergence.

5. Impact of technology In-situ incorporation of Sesbania after attaining 32-35 days

of sowing, and rice seedlings was transplanted 5 days after

incorporations. These were compared with normally

fertilized (100 N, 60 P2O5 and 40 K2O kg/ha) plots for

various parameters and found that, sesbania incorporated

plots had following advantages over without sesbania, those

are: Reduction in weed density by 57%, weed dry biomass

by 37%, curtailed the N, P2O5 and K2O requirement by 25%.

With sesbania plots measured 13.8% more panicle per unit

area, longer and heavier panicles with 21.1% lower chaffy

grains owing to these yield improvement by 16.4% than the

without sesbania plots.

6. Field plates

4. Effective and profitable weed management by herbicide use in wheat

S.No Particulars Details

1. Technology Effective and profitable weed management with newer

herbicide molecule in wheat

2. Developed by Dr. Anil Dixit and Dr. V.K. Choudhary ICAR-

NIBSM,Raipur

3. Year of

development/validation

2013-17

4. Rational Weeds are one of the primary producers within farming

systems; they are of prime importance to the arable food

system. The weed community provides a range of resources

for insect species, disease, birds and also hibernating place

for rodents. And therefore plays an important role in the

biological diversity of agro-ecosystems. However, weeds

are one of the major biological constraints to crop yield and

quality. Weeds such as Chenopodium album, Melilotus

alba, Medicago denticulata, Vicia hirsuta, Anagallis

arvensis, Euphorbia geniculata and Euphorbia hirta are

major broadleaved weeds and Echinochloa colona, Avena

ludoviciana and Phalaris minor were major grasses.

However, sedges density was negligible in wheat crop.

These weed causes 30-50% of yield loss by offering

competition for variable resources (e.g. light, moisture,

space, nutrients, CO2 etc.). As a result, growth and

development of crop was adversely affected owing to these

crop yield was considerably reduced. Use of single

molecule for longer time may cause weed shift and it

became ineffective. Under or over dose of recommended

molecules may lead to development of resistance biotypes.

These issues need to be addressed properly. The hypothesis

was that clodinofop propargyl will take care of grassy

weeds and metsulfuron methyl ensures to minimize the

density of broadleaved weeds. Therefore, ready mix

application of clodinofop propargyl 15% + metsulfuron

methyl 1% WP @ 64 g/ha at 20-25 days after sowing were

evaluated.

5. Impact of technology Ready mix application of clodinofop propargyl 15% +

metsulfuron methyl 1% WP @ 64 g/ha at 20-25 days after

sowing controlled the broadleaved weeds and grasses, and

recorded weed control efficiency of 82% than the weedy

plot. The effect of clodinofop propargyl 15% + metsulfuron

methyl 1% was more prominent with progress of crop

duration and weed control efficiency further improved. This

molecule was at par to weed control efficiency obtained

with two hand weeding at 20 and 40 days after sowing.

Clodinofop propargyl 15% + metsulfuron methyl 1% has

harvested with lees grain yield of wheat than the three hand

weeding (20, 40 and 60 days after sowing) but was

comparable to two hand weeding and recorded 40%

increased grain yield over one hand weeding at 20 days after

sowing. Comparison of economic parameters suggested that

clodinofop propargyl 15% + metsulfuron methyl 1% was

most profitable and economically viable option to adopt

weed management in wheat.

6. Field plates