关键词：
混合稀土;黄褐土;微生物生理类群;低剂量积累;E C50
摘 要：
采用田间小区试验和室内低剂量模拟叠加试验相结合的方法,研究低剂量外源混合稀土在黄褐土中积累对土壤微生物主要生理类群的生态效应。结果表明,外源低剂量稀土的持续积累会对土壤氨化细菌、硝化细菌、纤维素分解菌和自生固氮菌产生刺激、抑制、再刺激的交替作用。4种土壤微生物生理类群对混合稀土抑制敏感性依大小排序为:纤维素分解菌>氨化细菌>硝化细菌>自生固氮菌。对田间小区低浓度稀土积累下土壤微生物学数据进行模拟计算,稀土积累对纤维素分解菌、氨化细菌、硝化细菌和自生固氮菌的E C50(半抑制浓度)值分别为7.7～10.9、42.3～74.3、12.1～78.4和30.4～91.2m g·kg-1。稀土积累对参与有机碳转化的细菌类群比对参与氮素转化的细菌类群产生更强的抑制作用,纤维素分解菌可作为稀土积累生态效应的指示菌。由于土壤细菌对土壤生物活性的重要贡献,外源稀土在黄褐土中积累对细菌的安全临界值可以初步确定为10～30m g·kg-1。
译 名：
Ecological Effects of Major Soil Microbial Consortia in Yellow Cinnamon Soil After Receiving Low Dose of Rare Earth Elements (REEs)
作 者：
TANG Xin yun, SUN Yi yang, WEN Chong qing, ZHANG Zi li (School of Life Science, Anhui Agricultural University, Hefei 230036, China)
关键词：
mixed rare earth elements; yellow cinnamon soil; soil microbial consortia; low dosage accumulation; EC50
摘 要：
A combination and simulation method using plot tests in field was designed to study ecological effects of low dosage accumulation of added mixed rare earth elements (REEs) on major soil microbial consortia in yellow cinnamon soil. The continuous accumulation of REEs exhibited alternative effects of stimulation, inhibition and re-stimulation on soil ammonifying bacteria, nitrifying bacteria, nitrogen fixation bacteria and bacteria decomposing cellulose. The sensitivity of these four consortia to the inhibition of REEs was in an order: bacteria decomposing cellulose > ammonifying bacteria > nitrifying bacteria > nitrogen fixation bacteria. Soil microbial data were analyzed by computer and it was found that the median effect concentrations (EC50) of REEs were 7.7～10.9, 42.3～74.3, 12.1～78.4 and 30.4～91.2 mg·kg-1 for bacteria decomposing cellulose, ammonifying bacteria, nitrifying bacteria, and nitrogen fixation bacteria, respectively. REEs had stranger inhibitory effect on bacteria involving in organiccarbon decomposing than on that in nitrogen recycling. The bacteria decomposingcellulose could be taken as an indicative soil microbe for the ecological effect of REEs accumulation. As the important contribution of soil bacteria to soil biological activities, the EC50 value of 10～30 mg·kg-1 may be taken as critical value of mixed REEs added in yellow cinnamon soil.
