Ki Seon Hwang

A Survey of Weeds Occurrence on Paddy Fields in Chungnam Province in Korea

우리나라 농경지에 발생하는 잡초는 1972년 한국산잡초 목록(국립농업자재연구소)이 발간됨으로써 453종이 처음 으로 알려졌다(Lee et al., 2012). ‘논잡초 발생 양상에 관 한 연구’는 1971년에 처음으로 농촌진흥청 작물시험장 주 관으로 실시되었으며, 그 후 10년 주기로 현재까지 총 네 번의 조사가 이루어졌다(Kim, 1983; Park et al., 1995; Park et al., 2001; Park et al., 2002). 네 번에 걸친 논 잡초 발 생조사에서 우점 잡초의 순위에 많은 변화가 있었고, 경 지 이용형태의 변화, 토지 기반정비에 의한 입지조건의 변 화, 경종법, 재배관리, 특히 경운정지나 잡초 방제법의 변 화 등이 농경지에서 발생하는 잡초군락 천이의 주요 요인 으로 작용한 것으로 나타났다(Kim et al., 2012). 손제초에 의존하던 1970년대의 발생잡초의 비율을 보면 화본과 12%, 광엽잡초 50%, 방동사니과 19%, 기타 19% 등으로 나타났으며, 일년생과 다년생 잡초의 분포 비율이 7:3으로 일년생 잡초의 분포 비율이 높았고, 마디꽃, 쇠털 골, 물달개비, 알방동사니, 피, 밭뚝외풀, 가래, 사마귀풀, 올방개 순으로 우점하는 것으로 조사되었다. 뷰타클로르 입제와 같은 일년생 잡초 방제용 제초제의 사용이 증가된 1981년에는 화본과 7.4%, 광엽잡초 66.7%, 방동사니과 ABSTRACT. The survey of weed occurrence was conducted to identify problem weed species in the paddy field. The 320 sites of the 13 regions in Gyeongbuk Province were investigated from June to July, 2013. In the whole region, 51 weed species were identified including 34 annuals and 17 perennials. The highest importance value of annual weed and perennial was dominant 88.4 and 48.7%, in Gumi region, respectively. The most dominant weed species in paddy fields of Gyeongbuk Province were Monochoria vaginalis var. plantaginea (10.80%), followed by Lemna paucicostata (10.74%), Bidens tripartite (8.77%), Echinochloa oryzoides (7.17%), and Scirpus juncoides (6.20%). The similarity of paddy weeds in 13 regions observed through TWINSPAN analysis was distinguished by Ludwigia prostrata, Scirpus juncoides, Lindernia dubia, Polygonum aviculare, and Alopecurus aequalis var. amurensis. The weed species, Ludwigia prostrata, was divided into the four regions, Gyeongju, Gumi(direct seeding cultivation), Youngcheon and Euiseong and ten regions, Gumi, Bonghwa, Sanju, Goryung, Youngdeog, Pohang, Sanju, Andong, Yecheon, and Cheongdo.

Weed Flora and Management Practices in Peach Orchard Fields in Korea

In Korea, fruit represents one of the main categories of economic crops. The country’s fruit tree planted area was 155,000 ha in 2005, which is seven times larger than the acreage of orchards in 1955 (Ha and Chung, 2012). In particular, the area planted with peach trees has increased by around 3%, from 13,908 ha in 2011 to 14,210 ha in 2012. The yield of peaches ranked forefront in all fruits (Hong et al., 2012). In the face of the progressive increase in peach tree area, a series of problems have emerged in peach orchards, such as labor shortages, lagging product sales, and insufficient use of science-based management technologies. For these reasons, weed management methods are especially worthy of further study through surveys of weed flora. Weed flora is a common component of orchard ecosystems. On the one hand, an abundance of weed species can increase population diversity in orchards. A previous survey of weeds was carried out in the Chungnam region; its results showed that 75 weed species belonging to 26 families were identified in orchard fields and that Echinochloa crus-galli was the most dominant of the weed species with high densities (Choi et al., 2009a). Additionally, Park et al. (2005) reported that weed ranking in orchards according to dominance had changed compared to that reported a decade ago. On the other hand, weeds bring about some serious adverse effects for peach trees. These negative impacts are mainly divided into environmental and biotic effects. Environmental effects can mean competition for light, water, and nutrients between weeds and peach trees (MacRae et al., 2007). Peach tree yields, rootstock, and leaves are affected by weed competition (Tworkoski and Glenn, 2001). In contrast, the term ‘biotic effects’ can imply that weed species are known favorable hosts ABSTRACT. This study was carried out two surveys in 2015 to monitor weed occurrence and determine the most troublesome weeds in peach orchards of Korea. The first survey identified 56 taxa belonging to 23 families including 27 annuals, 11 biennials, and 18 perennials. Based on importance values, Conyza canadensis (5.12%), Plantago asiatica (4.17%), and Trifolium repens (3.86%) were the dominant weeds in the first survey (from April to June). Seventeen exotic weeds were identified in the first survey, including Conyza canadensis, Trifolium repens, and Chenopodium ficifolium. The second survey (from September to October) identified 42 weeds belonging to 19 families including 23 annuals, 5 biennials, and 14 perennials. According to importance values, Digitaria ciliaris (8.00%) was the most dominant weed, followed by Echinochloa utilis (6.61%) and Rorippa palustris (6.48%). There were 12 exotic weeds, including Taraxacum officinale, Rumex crispus, and Trifolium repens. Additionally, according to Braun-Blanquet’s scale showed that the dominance value was level 1 (41.98% and 46.43%, respectively) in two surveys. Currently, 40% of the total surveyed peach orchards applied herbicides for weed control. These results could provide basic data to assist orchardists in selecting the most suitable weed management methods; thereby, reducing labor inputs and effectively lowering costs while improving fruit yields in peach orchards of Korea.

The Survey of Weed Occurrence at Grape Orchard in Chungnam Province

This study was conducted to identify problematic weed species in grape orchard fields to establish basic information for suitable weed control. Surveys of weed species occurring in grape orchards were conducted in Chungnam province including Daejeon and Sejong of Korea from April to June and from September to October in 2015. From the surveys, 50 weed species belonging to 23 families (33 annuals and 17 perennials) were identified. In the first survey, the most dominant weed species by the importance values was Poa annua (7.07) followed by Echinochloa crus-galli (6.56), Digitaria ciliaris (6.43) and Capsella bursapastoris (5.63). In the second survey, Rorippa palustris (9.59), Eclipta alba (9.13), Digitaria ciliaris (7.68) and Poa annua (7.68) were dominant. Different weed species and dominance patterns were detected according to weed control methods in the grape orchards. Seven weed species belonging to six families were identified in the field in which herbicides were being used as a weed control method. However, most weed species (21 species belonging to 9 families) were occurred in the mowing + tillage fields. These surveys provide information about seasonal variations of weeds species occurred in grape orchards and impact of different weed control methods on the weed occurrence.