Previous Next End

WEED FLORA AND WEED DISTRIBUTION IN RICE ECOSYSTEM

Transplanted rice

It is the traditional method of cultivating rice is flooding condition

in which the young seedlings are transplanted from the nursery.

The predominant weed in the transplanted rice field

Previous Next End

Cynodon dactylon, Echinochloa colonum, Dactyloctenium aegyptium

and Chloris barbata among the grasses and among the dicot weeds,

Alternanthra pungens, Portulaca oleraceae, Eclipta alba and Tridax

procumbens were the predominant broad leaved weeds.

Echinochloa colona (L.) Link.

Previous Next End

It grows up to a height of 60 cm. Leaf-blade 7.5 to 15 cm long,

often blotched with purple or almost black cross bands ligule

0,2-5(9) cm. Inflorescence linear. Spiklelets ovoid-ellipsoid, to

2mm with fruit caryopsis.

It is propagated by means of seeds. It is an excellent fodder

It is annual grass grows commonly in waterlogged conditions

belonging to the family Gramineae. It is also called as jungle

rice and in tamil it is called as varnampul.

It is an annual grass belonging to the family Gramineae. It

is a mimic of rice. It grows upto 37cm height with no

ligule.Inflorescence an erect panicle with fruit ovate a

elliptic grain.

Previous Next End

It propagate by means of seeds.

Echinochloa crus-galli (L.) Beauv.

Previous Next End

It is an annual broad leaved weed also called as

Karasaranganm in the family Asteraceae.

 

Eclipta prostrata L. (Syn. Eclipta alba Hassk.)

Flower head is small, axillary and terminal. Fruit is Achenes. Propagate by means of seeds

Leaves opposite, sessile, linear and strigose..

It is diffusely branched stem is round and fleshy with strigose hairs

Previous Next End

Propagation by means of seed.

Belongs to Cyperaceae family. It is erect annual

sedge, with stem caespitoe to 30 cm ligule absent.

Inflorescence is compound and the fruit is nut obovoid.

Fimbristylis milliacea (L.) Vahl.

It is common in wet land ecosystem

Previous Next End

Veins are many and forking. Propagate by means of Stolons and spores

Marsilea quadrifolia L. (Pteridophyta)

The water fern belongs to the family Marsileaseae

also called as Arai keerai in Tamil. It is an

Amphibious herb with procumbent rhizomes.

Occurs in marshy areas, also in rice fields and

floating in running water. The stem is long creeping

stolon, rooting at the nodes. Leaves are erect on

long petioles. Leaflets are 4, rather large, obovate

and entire on the margin.

Previous Next End

It belongs to the family Graminae (Poaceae) and common

name is Bahama Grass, Hariyali. In tamil it is called as

Arugampullu.

In black soils and in dryland is a noxious weed and

once a field is infested with it, cultivation becomes

impossible. It is considered as one of the ten worst

weeds in the world and problematic in all tropical and

subtropical areas in dry land and garden lands.

Cynodon dactylon Pers.

A perennial grass extensively creeping by means of scaly rhizomes or by

strong flat stolons, very common in plains and hills sler and grows upto 7.5

to 30 cm height

The underground stems are hard, brittle, thick, pale white in colour and

covered with short scale-leaves and occur at varying depth in soil. Leaves

are linear, finely acute, 7.5 to 12.5 cm long, spikes 3 to 6. Spikelets are light

green or purplish, sessile, laterally compressed, alternately 2-seriate,

imbricate and 1-flowered.

Grain is minute, oblong somewhat flattened, rounded on black.

Propagated by through seeds and underground stolons.

Previous Next End

Previous Next End

Chloris barbata belongs to the family Poaceae and also

called as Mayil kondai pul. It is a tufed. A tufted perennial,

commonly found as a weed in dry cultivated fields.

Chloris inflata Link (Syn. Chloris barbata Sw.)

Culms upto 60 cm high. Leaves of 7.5 to 12.5 cm long.

Inflorescence with 6 to 15 digitately arranged spikes,

spikelets are usually purplish in colour.

Fruit is caryopsis. Propagation by seeds.

It is a good fodder grass

Previous Next End

Leaves flat, 5 to 20 cm long, glabrous. Fruit is

Caryopsis. Propagation by seeds. Cattle graze this

readily

Dactyloctenium aegyptium (L.) P. Beauv .

Dactyloctenium aegyptium (L.) P. Beauv is buffalo grass in the

family Poaceae. It is also called as Kakkakalpal in Tamil.

It is an annual, grass growing in waste places and dry cultivated lands.

Stem is Culms 10-62.5 cm high.

Previous Next End

The main stem is short and erect bearing a

number of lateral branches which lie prostrate

on the ground, they grow to a length of 4-20

inches and are green or reddish in color

Portulaca oleracea L.

It is a succulent broad leaved weed and

it belongs to the family Portulacaceae.

Common name is Indian Purslane.

In tamil it is called as Paruppu Keerai.

Previous Next End

The leaf-stalk is short. Flowers are without stalks, from 2-6 in

number and are collected together in clusters at the s of branches.

Sepals are 2 and fleshy; they are united at the base and are free

above.

Petals are 5 and are yellow in color. Fruit is dry, dehiscing

transversely by the upper part enclosed by the sepals, coming off as

a lid leaving the lower part in the plant.

Seeds are minute, blackish brown in color and are covered with

concentric lines of tubercles. Propagation is by seed.

Previous Next End

Alternathera pungens H.B. & K., (Syn. Alternanthera echinata S.)

An introduced weed from tropical America, now common in dry land, waste lands

and roadsides.

The plant is gregarious in habit and produces roots at the nodes for vegetative

propagation.

Alternathera pungens Broad leaved weed is also called as Khaki Weed and Mull

ponnanganny in Tamil.

It belongs to the family Amaranthaceae. It is a biennial wed

with trailing, diffusely branched habit.

The stem is round, hairy, slightly tinged with pink the

character of leaf is opposite, elliptic, obtuse and flowers in

auxiliary spikes and small with fruit Achene. Propagation by

means of seeds.

Previous Next End

Trianthema protulacastrum. L.

Trianthema protulacastrum.L. is annual prostrate herb belongs to the family Aizoceae.

In tamil it is called as Saranai.

Leaves are oppositve, petioled, petiole sheathing at the base, obovate, in unequal pairs.

Stem is round, striate, glabrous below and hairy.

Flowers is solitary and sessile.

Fruit is capsule.

Propagation by means of seeds and cuttings.

It grows gregariously grows causing considerable

hinderance to normal cultivation.

Previous Next End

Cleome chelidonii is the broad leaved weed belongs to the family Capparaceae.

Cleome chelidonii L. f.

Stem is covered with pointed hairs, leaf have long pertioled, digitately compound, flower is pink, bracteates with small bracts with capsule fruit and propagate by seeds

It is a erect glabrous much annual herb growing to a height of 30-60 cm.

Previous Next End

It is a annual herb grows upto a height of 1.5 m.

 

Parthenium hysterophorus L.

Parthenium hysterophorus L. is the generally found in non-cropped situation but now a days a weed of cropped field.

It belongs to the family Compositeae and commonly called as congress weed and visha poondu in Tamil.

Stem is slunder with hairs, leaves are alternate and sessile flower is white in colour with heads many.

Fruit is called as achene. Propagated through seeds.

Previous Next End

Ammannia baccifera (L.) m.

It Is an erect annual broad leaved herb growing up to a

height of 30 cm

Stem is tetragonus, branches at the base are long

becoming shorter towards the top.

It is Lythraceae family commonly called as

Blistering Ammania and in tamil called as Neermael

neruppu.

Leaves are small lanceolate, sessile and opposite.

Fruit is a capsule and propagate by seeds.

Flowers are axillary cluster; calyx tubular

Previous Next End

Direct seeded rice

Direct Seeded Rice (DSR) in place of the traditional transplanted rice is

a way to drastically reduce labor charges for nursery raising, puddling

and transplanting.

The predominant graminaceous weeds were Echinocloa crusgalli and

Panicum sp. and weed species belonging to family cyperaceae viz.,

Cyperus difformis and Cyperus iria.

The broadleaved weeds included Ammania baccifera, Eclipta alba,

Monochoria vaginalis and Marsilia quadrifoliata.

Previous Next End

Propagation by underground stems and grains.

Panicum repens commonly called as Ginger Grass and Inji pillu in tamil.  

Panicum repens L.

Stem is Culms creeping at the base, rhizomatous, 60 to 150 cm long.

Underground stems are thick and hard, very much resembling ginger.

It is a perennial grass, survive well under moist condition.

Aerial branches are covered with pointed scale leaves at the base.

Inflorescence is much branched terminal panicle 3-5 inches long. Spikelets is ovoid and pointed on a short stalk and has four glumes.

It is much relished by cattle.

Previous Next End

Cyperus difformis L. A common weed in paddy fields Cyperus difformis is also called as Vatta Korai

Belongs to family Cyperaceae.

Spikelets many, densely grouped into congested

globose heads; glumes obovate, apex rounded.

Propagation by seeds.

A very common sler, weak plant found in marshes and in shallow ponds; stems tufted, 12.5 to 37.5 cm long.

Stem 8-40 cm height. Leaves flaccid, as long as the stem; bracts 2-3, 5 to 20 cm long.

Previous Next End

Cyperus iria L.

Cyperus iria L. belongs to the family Cyperaceae and its tamil name is

Oosikorai.

It is widely distriubtued species an all marshy situations and also occurs as a very common weed in paddy fields and in shallow ponds.

Belongs to the family Cyperaceae and its tamil name is Oosikorai

It is erect glabrous annual.

Stem is 15 to 50 cm high, trigonous. Leaves up to 42.5 cm long; bracts 3-5, 5 to 25 cm long. Spike consists of 5-15 spikelets; spikelets linear, oblong, yellow or pale-brown and glumes plicate.Propogation by means of seeds.

Previous Next End

Monochoria vaginalis (Burm. f.)

Monochoria vaginalis is a common wet land and broad

leaved weed. It belongs to family Pontederiaceae.

A rooted aquatic herb, commonly growing in fresh

water and marshy areas. Root-stock short and

suberect. Flowers in racemes, usually blue spotted

with red and petaloid.

Fruit is a capsule. Propagation by

seed and also by root-stock

Previous Next End

Aerobic rice

Aerobic rice is a renewed way of growing rice in non-submerged

unpuddled condition in aerated soils.

Aerobic rice varieties developed for the

purpose yield as much as irrigated puddled rice

varieties traditionally grown in rice paddies.

The predominant weed flora found were Cynodon dactylon, Echinochloa

colonum, Dactyloctenium aegyptium and Chloris barbata among the

grasses and among the dicot weeds, Alternanthra pungens, Portulaca

oleraceae, Cleome chelidoni, Parthenium hysterophorus, Eclipta alba

and Tridax procumbens were the predominant broad leaved weeds.

Previous

Semidry rice cultivation is growing rice under rainfed condition

and later turning to lowland crop when rainwater is available

from the tanks and/or from similar sources.

The predominant weeds were

Semidry rice

Cynodon dactylon and Echinochloa colona among grasses, Trianthema portulacastrum and Portulaca oleracea among broadleaved weeds and Cyperus rotundus in sedges.