title: Suppression of the invasive plant mile-a-minute (Mikania micrantha) by local crop sweet potato (Ipomoea batatas) by means of higher growth rate and competition for soil nutrients.
abstract: BACKGROUND
  There are a variety of ways of increasing crop diversity to increase agricultural sustainability and in turn having a positive influence on nearby natural ecosystems. Competitive crops may provide potent management tools against invasive plants. To elucidate the competitive mechanisms between a sweet potato crop (Ipomoea batatas) and an invasive plant, mile-a-minute (Mikania micrantha), field experiments were carried out in Longchuan County of Yunnan Province, Southwest China, utilizing a de Wit replacement series. The trial incorporated seven ratios of sweet potato and mile-a-minute plants in 25 m(2) plots.
  
  
  RESULTS
  In monoculture, the total biomass, biomass of adventitious root, leafstalk length, and leaf area of sweet potato were all higher than those of mile-a-minute, and in mixed culture the plant height, branch, leaf, stem node, adventitious root, flowering and biomass of mile-a-minute were suppressed significantly (P < 0.05). The relative yield (RY) of mile-a-minute and sweet potato was less than 1.0 in mixed culture, indicating that intraspecific competition was less than interspecific competition. The competitive balance index of sweet potato demonstrated a higher competitive ability than mile-a-minute. Except pH, other soil nutrient contents of initial soil (CK) were significantly higher than those of seven treatments. The concentrations of soil organic matter, total N, total K, available N, available P, available K, exchange Ca, exchange Mg, available Mn, and available B were significantly greater (P < 0.05) in mile-a-minute monoculture soil than in sweet potato monoculture soil, and were reduced by the competition of sweet potato in the mixture.
  
  
  CONCLUSIONS
  Evidently sweet potato has a competitive advantage in terms of plant growth characteristics and greater absorption of soil nutrients. Thus, planting sweet potato is a promising technique for reducing infestations of mile-a-minute, providing weed management benefits and economic returns from harvest of sweet potatoes. This study also shows the potential value of replacement control methods which may apply to other crop-weed systems or invaded natural ecosystems.
authors: Agricultural Environment and Resource Research Institute, Yunnan Academy of Agricultural Sciences, Kunming, 650205, Yunnan, China. shenshicai2011@aliyun.com.
authors: Shicai
authors: S
authors: Shen
authors: Agricultural Environment and Resource Research Institute, Yunnan Academy of Agricultural Sciences, Kunming, 650205, Yunnan, China. xugaofeng1059@163.com.
authors: Gaofeng
authors: G
authors: Xu
authors: Biology Department, Trinity Western University, 7600 Glover Road, Langley, V2Y 1Y1, British Columbia, Canada. clements@twu.ca.
authors: David Roy
authors: DR
authors: Clements
authors: Agricultural Environment and Resource Research Institute, Yunnan Academy of Agricultural Sciences, Kunming, 650205, Yunnan, China. jgmbly2006@126.com.
authors: Guimei
authors: G
authors: Jin
authors: Agricultural Environment and Resource Research Institute, Yunnan Academy of Agricultural Sciences, Kunming, 650205, Yunnan, China. shenad68@163.com.
authors: Aidong
authors: A
authors: Chen
authors: Agricultural Environment and Resource Research Institute, Yunnan Academy of Agricultural Sciences, Kunming, 650205, Yunnan, China. fdzh@vip.sina.com.
authors: Fudou
authors: F
authors: Zhang
authors: Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, Miki, 761-0795, Kagawa, Japan. hisashi@ag.kagawa-u.ac.jp.
authors: Hisashi
authors: H
authors: Kato-Noguchi
mesh_terms: D000383:Agriculture / Q000379:methods*; D018533:Biomass; D002681:China; D018556:Crops, Agricultural / Q000254:growth & development; D058865:Introduced Species; D027723:Ipomoea batatas / Q000254:growth & development*; D035742:Mikania / Q000254:growth & development*; D057685:Plant Weeds / Q000254:growth & development; D012987:Soil / Q000737:chemistry*
chemical_list: D012987:Soil
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