SUBMITTED TO:

Prof. (Dr.) THOMAS ABRAHAM

DEPARTMENT OF AGRONOMY

ALLAHABAD SCHOOL OF

AGRICULTURE

SUBMITTED BY:

GROUP NO # 13

What is WEED….????

“Plant whose virtues are yet to be

discovered”

“A plant out of place”

Weeds are unwanted or undesirable

plants that compete with crops for water,

soil nutrients, light and space (i.e. CO2)

and thus reduce crop yields. Weeds

account for 33% loss in agriculture

alone.(Jethro Tull, 1731)

Successful Management Requires

Multiple approaches

Continual effort

Knowledge of the biology of weeds

species

Reproduction, lifecycle,

establishment annual, perennial,

wandering perennial, broadleaf,

grass.

Weed : Top issues for Organic

Farmers

Principles Involved:

Eco Friendly :- i.e. it should cause no harm to

our environment.

Break the survival mechanism of the weed in

soil.

Easily acceptable by the progressive farmers.

Crop husbandry ( Crop Rotation, Mulching

etc.)

Multiple Prevention and

Elimination Strategies

(Practices):

Cultural

Biological

Physical

Mechanical

“Many hammers approach.”

Liebman and Gallandt, 1997

Cultural Strategies

Buy quality crop seed with low/no weed seeds

present.

Do not allow weeds to form seed.

Improve crop competitiveness

Improve soil tilth, aeration, and fertility to

optimize crop growth

Increase crop density through narrow

row spacing and increased seeding rate

Use transplants, rather than seed, when possible

Cultural Practices

Reduce weed numbers

Mulch (wood chips, mow and blow, paper,living, plastic, etc)

Use weed-suppressive cover cropsQuick germinating, high biomass

Field with high weed pressure may warrant full year ofcover cropping and fallow to reduce weeds

Crop rotationsaltering narrowly spaced crops with closely spacedcrops, shallow rooted/deep rooted crops, cold/warmseason crops

IntercropClover underseeded in sweetcorn.

Mulches

Wood

chips

Shredded

paper

Leave

s

Stra

w

Cover Crops

Field pea-oat-

mustard cover cropRed Clover

Crop Rotations

• Weeds tend to infest crops with similar

life cycles.

• Change crop ecology: shallow/deep

roots, cold/warm season, row/drilled

crops, foliage density, and heavy/light

feeders.

Change cultural practices: cultivation,

mowing, fertilization, herbicide

application, and planting/harvest dates

Biological Control Practices

Insects: may consumelarge numbers of weedseeds or feeding injury toplant or vector virus

Phyllocoptes fructiphilus hasbeen shown to transmit roserosette disease on young fastgrowing roses

Selective grazingSheep: clean fields afterharvest

Weeder geese: useful againstgrass weeds and in perennialsystems

BiofumigationUse of Brassica species (canola, Indian mustard) as cover crop or in rotation

May be incorporated or left as residue

Brassicas produce glucosinolates, which may by converted to cyanate compounds during decomposition.

Sustainable Vegetable Production from Start-Up to Market, Grubinger, 1999

Allelopathy

Allelopathy is the direct or indirect chemical effect

of one plant on the germination, growth or

development of neighboring plants.

Species of both crops and weeds exhibit this

ability. Allelopathic crops include barley, rye,

annual ryegrass, buckwheat, oats, sorghum, sudan

sorghum hybrids, alfalfa, wheat, red clover, and

sunflower.

The alleopathic effect can be used to an advantage

when oats are sown with a new planting of alfalfa.

Physical and Mechanical

Practices

Mowing

Prevents seeding

Depletes storage reserves

Better control for broadleaves

Soil solarization

Effective control of winterannuals

Limited control of perennials

Cost prohibitive on largeacreages

Avoid tillage deeper than 3”after solarization

Hand weeding

Cultivation

( done with cultivators)

Flaming

Flaming

Intense heat sears the leaf,causing the cell sap toexpand and disrupt cellwalls

seedlings are mostsusceptible

Broadleaf weeds are moresusceptible than grasses

May be used in wet soilconditions Sustainable Vegetable Production from Start-Up to Market, Grubinger, 1999

Crop Map Of Jharkhand:

Weed Management of RICE

( Major crop ) In Jharkhand.

Few weed species are

Echinochola crus-galli

Echinochloa colona

Eclipta alba

Monochoria vaginalis

Cynodon dactylon

Cyperus iria

Cyperus difformis

Cyperus rotundus

If these weeds are not

controlled from very

beginning the

reduction in rice

yield may be as high

as 12-98%.

Critical Period :

30 t0 70 DAS

Control:

Cultural control :

Keeping a layer of water (7 cm -15cm) on rice is said to

suppress germination of weeds completely.

Biological control :

Very little is known about natural enemies of this

sedge; the fungi, Corticum sasaki , and the

nematode Meloidogyne graminicola, may be considered

for biological control.

Mechanical Control:

Hand picking is the most commonly used process

practiced for weed management in Jharkhand.

Weed Management of POTATO(

Major crop ) In Meghalaya.

Most common weed associated are:

Witchgrass-Panicum capillare

Dense hairs cover the leaf blades on both

sides and the sheath

Leaves are rolled in the bud and lack

auricles

Leaves have a white mid-vein

Its is a nuisance in lawns and gardens

It has a fibrous root system

Mature plants are 1 to 2’ tall

A.K.A. ‘ticklegrass’

Control:

Prevention:Learn to identify plants; start

monitoring early in the season.

Cultural Weed Control:

Plant competitive grass or other cover

crops. Witchgrass does not compete well with

perennial grasses.

Mechanical Weed Control

Cultivation or mowing before seed develops will

control this plant. Witchgrass can also be hand

pulled.

Biological Control :

No known biological control in our area.

Weed Management of SUGARCANE

( Major crop ) In Uttar Pradesh.

Most common

weeds associated

are:

Sorghum halepense

Cyperus rotundus

Eleusine indica

Saccharum

spontaneum

Digera arvensis

Eclipta alba

Cynodon dactylon

Pyllanthus niruri

If these weeds are not

controlled from very

beginning the

reduction in

sugarcane yield may

be as high as 10-70%.

Critical period for

weed competition

is 4 months after

sowing.

Control:

Cultural Weed Control:

Selection of cultivars that have quick canopy closure.

Seed cane from clean fields.

Trash mulch at 45 DAP @ 7-10 t/ha,10 cm thick is

effective against many weeds.

Mechanical Weed Control

Plant cane-scratchers are used over the top of the

cane and tines are removed as the can gets larger.

Ratoon cane-disk cultivators are used for weed

control in row middles.

Biological Control : Not practiced in Uttar Pradesh.

Weed Management of PINEAPPLE

( Major crop ) In Nagaland

Matricaria matricarioides ( Pineapple weed ):the most common associated weed.

Plant stems grow erect up to 1’ tall

Heads are cone-shaped and a yellowish green colour

with each head surrounded by overlapping bracts with

no ray petals

Crushed heads give off an odour likened to pineapple.

An annual plant reproducing by seeds

It is a nuisance in lawns and gardens and is also found

in croplands and along roadsides.

Control:

Prevention – Learn to identify plants; start monitoring

early in the season

Biological – No known biological control in our area

Cultural –

One hand weeding in May/June.

For the treatment involving mulching, non-decomposed

coffee husk was uniformly applied at a rate of 20 tons ha-

1 as per the schedule & mulched treatments significantly

out- yielded treatments without mulch and the clean

weeding with 100% weed control efficiency.

Conclusion

Using multiple approaches (“many

hammers”) to manage weeds will yield

greater impact than relying on a few

practices.

Develop a weed management strategy

that is designed for the needs of your

farm.

Although weeds can serve as host plants

for pests, they can also serve as hosts to

beneficial organisms

Conclusion

Today, however, with the increase in organic

farming and the decrease in the use of

herbicides, breeding for weed suppression

has become a higher priority.

Instead of eradicating weeds, farmers

especially organic farmers-- are learning to

manage weeds.

THANKING YOU

GROUP NO # 13