Phytoremediation in mined rare earth land and its effect on seed bank in soil

Transcription

1 Journal of Zhongkai University of Agriculture and Engineering Vol 28 No 4 December 2015 DOI /j issn * m A B C D A /m 2 3 B C D /m X826 A Phytoremediation in mined rare earth land and its effect on seed bank in soil XU Weifeng CHEN Ruzhou LIU Shenghong LIANG Hong * College of Life Sciences Zhongkai University of Agricultural and Engineering Guangzhou China Abstract In order to observe phytoremediation in mined rare earth land and understand the effect of phytoremediation on the seed bank in soil this study was carried out in the mining rare earth area in Renju town Pingyuan County Guangdong Province The investigations of plant species and seeds bank were conducted in restored and mining area and 30 m apart from rare earth land marked as A B C and D plots respectively The results showed that 1the vegetation coverage in restored area increased during phytoremediation but the species of the vegetation decreased to 8 in November 2014 compared with 16 species in November 2013 and the native plants were dominant gradually 2seed density A plot /m 2 in restored area was higer than those in the mining area B plot 3 13 /m 2 C plot 1 50 /m 2 D plot 1 25 /m 2 in september 2013 and plant species were higher than that in restored and mining areas in september the seed density of mining area was lower than restored area in both years and most of the species were spread from restored area The similarity of seeds bank in the adjacent region was higher than the non-adjacent region This study revealed that phytoremediation was obviously effective in species diversity in rare earth area and had an important affect on seed banks in soils both in the restored increasing plant and adjacent areas Key words rare earth mine seed bank phytoremediation dominant species KJCX * lhofice@ 163 com

2 m m kg /m kg /m Stylosanthes scabra Vog cv Xika 0 5 m 1 0 m Vetiveria zizaniodes Paspalum conjugatum Medicago sativa 1 5 m 3 0 m m 1 0 m Zea mays Pinus massoniana Vernicia montana Simpson 1 10 = / 100 = / = / ' 24 33' 500 ~ 600 m mm 309 d = + + Simpson D Concentration D = 1 - P 2 i A m B C D cm 25 cm Fig 1 Landscape of the rare earth mine before phytoremediation 5 cm

3 Serensen S = 2w / a + b 20 cm45 cm 1 a A b B 10 cm w A B 5 mm g d A B C D Miscanthus floridulus Blechnum orien- talesimpson 2 Serensen 12 A Artificial vegetation in Nov 2013 B Mixed vegetation of cultivated and native in May 2014 C Native dominant vegetation in Nov Fig 2 Change of vegetation in rare earth mines during phytoremediation 2 2 A B C D Erigeron annuus Digitaria somguinalis Echinochloa crusgalli Malachium aquaticum

4 4 19 Table Plant species in the phytoremediation area in November 2013 Relative Relative coverage / density / Relative frequency Important value / Simpson Simpson Trema rientalis Pteridium aquilinum * Paspalum conjugatum Blechnum orientale Morinda parvifolia * Pinus massoniana Miscanthus sinensis Litsea cubeba * Vetiveria zizaniodes Dicranopteris pedata * Vernicia montana Smilax china Miscanthus floridulus Gahnia tristis Bambusa textilis Aster subulatus * Artificial planting Table Plant species in the phytoremediation area in May 2014 Relative Relative coverage / density / Relative frequency Important value / index Simpson Simpson Miscanthus sinensis Trema rientalis Miscanthus floridulus * Pinus massoniana Blechnum orientale Pteridium aquilinum Aster subulatus Solanum nigrum Dicranopteris pedata * Vernicia montana Eragrostis ferruginea Gynura crepidioides * Paspalum conjugatum * Artificial planting Table Plant species in the phytoremediation area in November 2014 Relative Relative coverage / density / Relative frequency Important value / Miscanthus floridulus * Paspalum conjugatum * Pinus massoniana Blechnum orientale Eragrostis ferruginea * Vetiveria zizaniodes Trema rientalis Dicranopteris pedata * Artificial planting index Simpson Simpson index

5 20 28 Table Seed bank in soil in restoration and adjacent mined areas in September 2013 A A plot B B plot C C plot D D plot Erigeron annuus Digitaria somguinalis Erigeron canadensis Echinochloa crusgalli Oxalis corniculata Polygonum plebeium * Celosia cristata African marigold Malachium aquaticum Total * Artificial planting 5 Erigeron canadensis Celosia cristata Solanum nigrum Table Seed bank in soil in restoration and adjacent mined areas in September 2014 A A plot B B plot C C plot D D plot Erigeron annuus Erigeron canadensis Celosia cristata Solanum nigrum Total A C D B C D C D A B Table 6 6 similarity between restoration area and adjacent mined areas A A plot B B plot C C plot D D plot Soil source Similarity Common species Similarity Common species Similarity Common species Similarity Common species A A plot B B plot C C plot D D plot

6 A B C D A B C D Table 7 Seed densities of restoration and adjacent mined areas A B C D Sampling period A plot B plot C plot D plot September September

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