Floristic Composition of Weeds in Paddy Fields in Mahendranagar, Nepal

Abstract

Field experiments were conducted during 2004 and 2005 in paddy fields to evaluate the floristic composition of weeds, in lowland and upland areas of Mahendranagar, Nepal. A total of 61 weed species belonging to 42 genera and 23 families were recorded. Of the 23 families, Cyperaceae was the largest (13 spp.), followed by Poaceae (11 spp.), Euphorbiaceae (4 spp.), Amaranthaceae, Commelinaceae and Asteraceae (3 spp. each), Polygonaceae (2 spp.) and one species each belonged to Apiaceae, Acanthaceae, Alismataceae, Pontederiaceae, Leguminosae, Convolvulaceae, Eriocaulaceae, Marsileaceae, Malvaceae, Oxalidaceae, Onagraceae, Parkeriaceae, Portulaceae, Rubiaceae and Verbenaceae. The number of weed species was higher in upland (55) when compared with the lowland sites (48). On the basis of Importance Value Index (IVI) dominating weed species in paddy fields were: Fimbristylis miliacea (13.4), Lindernia oppositifolia (13.2), Eleocharis atropurpurea (13.1), Ageratum conyzoides (13.0), Cyperus iria (13.0), Echinochloa crus-galli (11.9), Ischaemum rugosum (11.7), Echinochloa colona (11.4), Cyperus difformis (11.1) and Schoenoplectus juncoides (11.0). Besides dicots and monocots, two species of pteridophytes (Ceratopteris thalictriodes and Marsilea minuta) were also recorded in lowland paddy fields.

Distribution pattern and multifarious use of weeds in rice agro-ecosystems of Bhadrak district, Odisha, India

“…The highest contribution of family Poaceae is in accordance with Turki & Sheded (2002) and Hakim et al (2013). The species listed in this study are also reported as weeds in other countries (Dekker 1997, Qiang 2002, Bhatt et al 2009, Hakim et al 2010, Jaya Suria et al 2011. In fact, from the recorded 12 species of Asia's worst weed (IRRI 2010), Bhadrak district harbors seven weed species (Cyperus iria, Cyperus difformis L., Echinochloa colona, Ischaemum rugosum, Leptochloa chinensis Nees, Ludwigia hyssopifolia, Sphenochlea zeylanica Gaertn.).…”

“…It finds a place on the list of 10 worst weeds of the world (Noda 1977). Echinochloa crusgalli is reported as a dominant weed in rice fields of Malaysia (Hakim et al 2010), Nepal (Bhatt et al 2009), Pakistan and India (Parameswaran et al 2014). While studying the weed community of Zhejiang Province, southeastern China Yu et al (1993) stated that Echinochloa crusgalli is the dominant weed species of the early and late rice stages respectively.…”

Spring weed communities of rice agrocoenoses in central Nepal

“…40-60 species (e.g. Manandhar et al 2007, Bhatt et al 2009, Sapkota et al 2010. The richness of rice agrocoenoses is surely related to the extremely rich species pool in the whole country.…”

“…This number is still being amended upwards (Ferille andLachard 2013, Nobis et al 2014a, b). Around 218 vascular plants were reported as weeds of rice paddy fi elds (Moody 1989, Bhatt et al 2009). …”

“…Weeds are considered one of the major problems in rice production in Asia, including Nepal (Papademetriou et al 2000, Bhatt et al 2009). Losses due to weeds have been estimated at 12% of the crop yields (Manandhar et al 2007).…”