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United States Department of Agriculture

Agricultural Research Service

Research Project: Discovery and Development of Natural Product-based Weed Management Methods

Location: Natural Products Utilization Research

Title: Simulated acid rain alters litter decomposition and enhances the allelopathic potential of the invasive plant Wedelia trilobata (Creeping Daisy)

Authors
item Wang, Rui Long -
item Staehelin, Christian -
item Dayan, Franck
item Song, Yuan Yuan -
item Si, Yi Juan -
item Zeng, Ren Sen -

Submitted to: Weed Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 12, 2012
Publication Date: July 1, 2012
Citation: Wang, R., Staehelin, C., Dayan, F.E., Song, Y., Si, Y., Zeng, R. 2012. Simulated acid rain alters litter decomposition and enhances the allelopathic potential of the invasive plant Wedelia trilobata (Creeping Daisy). Weed Science. 60:462-467.

Interpretive Summary: Invasive weeds often produce a number of naturally herbicidal compounds (allelochemicals) that helps then compete against native species. Creeping daisy (Wedelia trilobata) is one such allelopathic plant invading areas of southern china, where acid rain is prevalent. This study investigates whether acid rain has an effect on the allelopathic properties of creeping daisy. Our results show that stimulated acid rain causes the soil containing residue of creepy daisy to be more phytotoxic than the control soils. Therefore, acid rain may be an added contributing factor facilitating the spread of this invasive plant species.

Technical Abstract: Invasive species and acid rain cause global environmental problems. Limited information exists, however, concerning the effects of acid rain on the invasiveness of these plants. For example, creeping daisy, an invasive exotic allelopathic weed, has caused great damage in southern China where acid rain is prevalent. To better understand the effect of acid rain on creeping daisy, we investigated the impact of simulated acid rain (SAR) on its litter decomposition, soil nutrients and the allelopathic potential of soil surrounding the litterbags. Litter was treated with SAR at different acidity (pH 2.5, 4.0, 5.6) or with water (pH 7.0) as a control. After 70 days, the remaining amount of creeping daisy litter, nutrient contents and allelopathic potentials in the surrounding soil were determined. The litter decomposition was commensurate to the increase in the acidity of the SAR. Total C and N contents, NO3--N and available P increased, levels of NH4+-N, the ratio of C/N and soil pH values decreased, water contents increased and then decreased, whereas available K did not significantly change in the soil surrounding the litter in response to SAR. Bioassays showed that SAR promoted the allelopathic activity in the soil surrounding the litter, as measured by seedling growth of turnip and radish. In conclusion, our results indicated that SAR influenced edaphic factors, accelerated creeping daisy litter decomposition and enhanced the allelopathic potential of soil surrounding its litter. Hence, acid rain may enhance the invasiveness of creeping daisy plants.

Last Modified: 7/30/2014
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