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weeds of rice July 19.pptx
- 1. Important Weed Flora of Transplanted and Direct Seeded Rice Presented by Pratima Pokhrel WS-01M-2023
- 2. Rice Rice (Oryza sativa) is the major cereal crop and is staple food to about 3 billion population of the world. Rice is the major cereal crop in Nepalese agriculture both in the area of 1.47 million ha as well as production of 5.15 million tons. In Nepal, rice is planted mainly by two principal methods i.e. transplanting and direct seeding method. The problem of weed competition with rice is of great economic importance in the country because it causes a 10–35% reduction in grain yield.
- 3. Direct seeded rice: Direct seeding is a crop establishment system wherein rice seeds are sown directly into the field. Transplanted rice : Transplanting consists of preparing seedlings in nursery and then planting these seedlings in the prepared main field.
- 4. Weed is an unwanted plant. Generally, plant in wrong place called as weed. Grasses are dominant in irrigated/ transplanted systems. Sedges are dominant in rainfed systems. Weed problems are more severe in aerobic and direct-seeded rice when compared with irrigated rice. Nearly 134 weed species identified from rice field belongs to 32 taxonomic families. The study of how a weed interacts with other plants, its habitat, and other weeds is known as “weed ecology”. Weeds of rice and their ecology
- 5. Weeds of Direct-Seeded Rice
- 6. Grasses Scientific name: Cyperus difformis Common name: Common sedge(motha) • Family: Cyperaceae • Ecology: This is an annual herb with one to many thin, soft erect stems reaching over 30 centimeters in maximum height. • The small flower umbrella plant grows well in flooded or moist fertile soils and common in lowland rice. • found on poorer sandy or clay soils in fallow lands. • propagates by seeds and produces seeds throughout the year. Scientific name: Leptochloa chinensis Common name: Red sprangletop Family: Poaceae Ecology: Red sprangletop propagates by seeds or vegetatively by rootstocks. Germination does not occur when seeds are submerged in water. L. chinensis grows from near sea-level up to 1400 m altitude. Germination was strongly stimulated by light and warm fluctuating temperatures
- 7. Scientific name: Ludwigia perennis Common name: False primerose (ल्वा झार) Family:Onagraceae Ecology:Upland.It is highly tolerant of fluctuating water levels. • The periderm of the plant tissues swells rapidly when immersed in water: this is probably a defence against waterlogging . • Responds strongly to application of nitrogenous fertilizer (up to 100 kg/ha) by increased dry matter accumulation, which may increase problems of weed control in heavily fertilized ricefields. Common name: Scirpus spp. (Bulrush) Scientific name: Scirpus Family: Cyperaceae Order: Poales • Ecology: Perennial weed of low land paddy • Erect and strongly tillering upto 0.75m • Dormancy:2-3 months • Elevation: upto 2000
- 8. Broad leaf weeds Scientific name: Monochoria vaginalis Common name: Pickerel weed Family: Pontederiaceae • Ecology: M. vaginalis is a fleshy, tufted, annual or perennial herb with a glabrous, shiny appearance and a short rhizome. • Reproduction is mainly from seed, with occasional new growth from tubers. • Its property of discontinuous germination allows it to evade control. Scientific name: Sagittaria sagittifolia Common name: Arrowhead Family: Alismataceae Ecology: Sagittaria sagittifolia is a stoloniferous aquatic perennial herb that reproduces by seed, plant division, and tubers • The plant spreads, forming large stands in areas of slow moving or stagnant water. • Very difficult to fully control due to the ability of the plant to regenerate from fragments and the extensive rhizome system.
- 9. Scientific name: Commelina benghalensis Common name: Benghal dayflower, tropical spiderwort, Family: Commelinaceae Ecology: Found on upland, lowland, disturbed sites, forest edges, road sides, agricultural sites, and home gardens. Moist to dry places • Germinates best in full light; somewhat tolerant of herbicides; annual in temperate zones; prefers high • fertility; single plant can cover a large area; useful forage and human food. Scientific name.: Ammania baccifera Common Name: Agni buti Family: Lythraceae Ecology: It is annual, dicot and herbaceous plant and can be found in marshes, swamps, rice fields and water courses at low elevations during rainy season. A. baccifera occurs in wet locations, very often as a weed in rice fields in the lowland, up to 1200 m altitude. Maximum alkaloid synthesis was found in plants at the fruiting stage, under moderate light intensity and with a photoperiod of 16 hours. The application of NPK-fertilizer enhanced the alkaloid
- 10. Scientific name: Lindernia spp. (Lindernia) Common name: Oonmudia Family: Scrophulariaceae Ecology: Small annual or perennial weed, reproducing by seed,; particularly rice fields, grassland, irrigated crops. Scientific name: Eclipta alba Common name: False daisy(jal bhangra) Family: Asteraceae Ecology: Found in: lowland, upland; Growth habit: herb; prostrate to erect, much-branched; up to 1.0 m; Life cycle: annual; reproduction: via seeds; no emergence from depth; C3 plant; saline-tolerant; often in fi eld margins; somewhat tolerant of butachlor
- 11. Scientific name: Hedyotis spp. (Hedyotis) Common name:Hedyotis Family: Rubiaceae Ecology: Herbs or subshrubs, apparently biennial or perennial, found in tropical and subtropical wastelands Scientific name: Aeschynomene spp Common name: Aeschynomene Family: Leguminosae Ecology: It is an annual or perennial herb, that often grows in wet, muddy habitat, such as floodplains, swamps, and paddy fields, found in tropical and subtropical regions and elevation: up to 1,500 m, reproduce via seeds, C3 plant
- 12. Scientific name: Rotala spp. Common name: Rotala Family: Lythraceae Ecology: Aquatic perennial plant, found in a semi-emersed state at the edges of paddies and in moist areas, fast growth rate, Temperature: 22-28°C.
- 13. Scientific name: Panicum spp. Common name: Panicgrass Family: Poaceae Ecology: Native throughout the tropical regions of the world, They are often large, annual or perennial grasses, growing to 1–3 m tall, ; drought-tolerant; reproduction: rhizomes, seeds; prefers sandy soils; acid- and salt-tolerant; deep plowing increases rate of spread; after establishment can survive moderate drought; fodder Scientific name: Fimbristylis spp. (Fimbristylis) Common name: Jwane jhar Family: Cyperaceae Ecology: may emerge throughout season; may produce multiple generations in one season; Found in upland and low land; very heterogeneous species; saline-tolerant; C4 plant; better adapted to drier soils; useful for mat-making Sedges
- 14. Scientific name:Echinocloa glabrescens Common name: Samo ghans Family: Poaceae Ecology: Adapted to wet places, It grows on ditches, low areas in fertile croplands and wet wastes, often growing in water, one of the world’s worst weeds; soil saturation strongly reduces emergence of buried seeds; responsive to nutrients; profuse root production; good forage; C4 plant; encouraged by zero tillage Scientific name: Echinochloa crusgalli Common name: Banyard grass (sawank) Family: Poaceae Ecology: Adapted to wet places, grows on ditches, low areas in fertile croplands and wet wastes, often growing in water, one of the world’s worst weeds; soil Saturation strongly reduces emergence of buried seeds; responsive to nutrients; profuse root production; good forage; C4 plant; encouraged by zero tillage
- 15. Scientific name: Cyperus rotundus Common name: Purple nut sedge(motha) Family: Cyperaceae Ecology: Found in cultivated fields, farmlands, neglected areas, wastelands, grasslands, at the edges of forests, and on roadsides, sandy or gravelly shores, riverbanks and irrigation canal banks; elevation: upto 1800 m; C4 plant; saline-sensitive; tubers may be viable for several years; tubers consumed by humans; forage Scientific name: Digitaria ciliaris Common name: southern crabgrass (chitrey banso) Family: Poaceae Ecology: Found in tropical and temperate regions; tolerates defoliation; Growth habit: creeping, tufted with prostrate to erect culms; up to 0.6 m very responsive to nutrients; C4 plant; shade-sensitive, reproduce via seeds, Elevation: up to 2,000 m
- 16. Scientific name: Cyperus iria Common name: Yellow sedge Family: Cyperaceae Ecology: Found in: lowland, upland; Growth habit: erect; tufted up to 0.8 m; Elevation: up to 1,200 m; germinates best in full light; C4 plant; may have multiple generations in one season; prefers lower elevations Scientific name: Eleusine indica Common name: Goose grass (Kode jhar) Family: Poaceae Ecology: Found in: upland; Growth habit: stems erect or ascending, branched; upto 0.6 m; one of the world’s worst weeds; C4 plant; multiple generations in one season; can emerge from soil depths of up to 0.08 m; Elevation: up to 2,000 m; reproduce via seeds
- 17. Scientific Name: Leptochloa mucronate Common Name: Red Sprangletop, Sprangletop Family: Poaceae Ecology: Suited to tropical, subtropical or warm temperate climates; Growth habit: tufted, erect, and slender; sometimes with reclining stems; up to 1.2 m Scientific name: Ischaemum rugosum Common Name: Wrinkle grass Family: Poaceae Ecology: Growth habit: tufted, ascending to erect, and much branched; up to 1.0 m; Life cycle: perennial; Elevation: up to 2,400 m Light: sunny; shade-tolerant; red leaf sheaths at the base; new seedling cohorts emerge after drainage from up to 0.05 m soil depth; responsive to fertilizer; acid-tolerant; good forage if young; germinates on surface of saturated soil; C4 plant
- 19. Broadleaf weeds • Scientific name: Eclipta alba • Common name: False daisy(jal bhangra) • Family: Asteraceae • Ecology: This species grows commonly in moist • places as a weed in warm temperate to tropical • areas worldwide. Scientific name: Commelina benghalensis Common name: Benghal dayflower, tropical spiderwort, Family: Commelinaceae Ecology: Found on upland, lowland, disturbed sites, forest edges, road sides, agricultural sites, and home gardens. Moist to dry places
- 20. Scientific name: Alternanthera sessilis Common name: sessile joyweed(Bhirung) Family: Amaranthaceae Ecology: found in lowland and upland, Moisture: wet to moist; more terrestrial than aquatic lowland, upland Growth habit: prostrate, creeping or ascending; many suberect branches, up to 1 m Moisture: wet to moist; more terrestrial than aquatic Competitivfloodingeness: moderate Seed contaminant: unknown Cultural control: flooding, hand weeding or tillage Scientific name: Ageratum conyzoides Common name: Tropic weed, goat weed Family: Asteraceae Ecology: Found in moist to dry place of land annual Seed wt: 0.1 Method(s) of reproduction: seeds Maturity time: quick fl owering and short-lived, as little as 2 months Dormancy: 50% of seeds can germinate immediately; light required for germination Flower: white to pale purple/blue Elevation: up to 3,000 m Light: shade-tolerant
- 21. Scientific name: Amaranthus spinosus Common name: Spiny amaranth, Spiny pigweed Family: Amaranthaceae Ecology: Life cycle: annual Seed wt: 0.2 Method of reproduction: seeds; no light requirement for germination; Flower: pale green-purple tinge; Elevation: up to 1,800 m Light: sunny; shade-sensitive; ; C4 plant; prefers fertile soils and higher temperature
- 22. Scientific name: Cynodon dactylon Common name: Bermuda grass, dubo Family: Poaceae Ecology: Growth habit: prostrate to ascending; up to 0.4 m; Life cycle: perennial Seed wt: 0.3 reproduction: rhizomes and stolons, seeds; Elevation: up to 2,300 m; C4 plant; alkaline and acid-tolerant; flood- and drought-tolerant; numerous biotypes Sedges Scientific Name: Echinochloa colona Common name: Shama millet (सामा घााँस) Family: Poaceae Ecology: Growth habit: tufted and erect; up to 0.6 m; Life cycle: perennial; reproduction: seeds, stolons; Elevation: up to 2,000 m; soil saturation strongly reduces emergence of buried seeds; responsive to nutrients; profuse root production; good forage; C4 plant; encouraged by zero tillage
- 23. Scientific name: Digitaria ciliaris Common name: southern crabgrass (chitrey banso) Family: Poaceae Ecology: Found in tropical and temperate regions; tolerates defoliation; Growth habit: creeping, tufted with prostrate to erect culms; up to 0.6 m very responsive to nutrients; C4 plant; shade-sensitive, reproduce via seeds, Elevation: up to 2,000 m Scientific name: Panicum spp. Common name: panicgrass Family: Poaceae Ecology: Native throughout the tropical regions of the world, They are often large, annual or perennial grasses, growing to 1–3 m tall, ; drought-tolerant; reproduction: rhizomes, seeds; prefers sandy soils; acid- and salt- tolerant; deep plowing increases rate of spread; after establishment can survive moderate drought
- 24. Scientific name: Imperata cylindrica Common name: blady grass, cogon grass(sirru) Family: Poaceae Ecology: Found in: upland; Growth habit: erect, tufted, and unbranched; scaly rhizomes; up to 2 m; perennial reproduce via seeds and rhizome; C4 plant; acidand alkaline-tolerant; prefers light-textured soils; many infested fields are abandoned; burning does not injure rhizomes Scientific name: Panicum spp. Common name: panicgrass Family: Poaceae Ecology: Growth habit: creeping; erect and branching stems; up to 1.0 m; Growth habit: creeping; erect and branching stems; up to 1.0 m; Life cycle: perennial; reproduction: rhizomes, seeds; prefers sandy soils; acid- and salt-tolerant; deep plowing increases rate of spread; after establishment can survive moderate drought
- 25. Scientific name: Scripus junicoides Common name: Club rushes Family: Cyperaceae Ecology: Found in lowland rice, shallow ponds, streams, and drains. Emerges directly from seeds; Scientific name: Eleusine coracana Common name: crowfootgras (kode banso) Family: Poaceae Ecology: Both upland and lowland
- 26. Thank you!!!