| 刁展,吕家珑,安凤秋.外源铅在土壤中的年际变化及对土壤有机碳矿化和速效养分的影响[J].干旱地区农业研究,2017,35(4):10~14 |
| 外源铅在土壤中的年际变化及对土壤有机碳矿化和速效养分的影响 |
| Annual variability of exogenous lead in the soil and its effect on soil organic carbon mineralization and available nutrients |
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| DOI：10.7606/j.issn.1000-7601.2017.04.02 |
| 中文关键词: 外源铅 有机碳 微生物量碳 速效养分 |
| 英文关键词:exogenous lead soil organic carbon microbial biomass carbon soil available nutrients |
| 基金项目:公益性行业(农业)科研专项“主要农产品产地土壤重金属污染阈值研究与防控技术集成示范”(200903015) |
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| 中文摘要: |
| 以关中娄土为供试土样进行田间试验，向耕层土壤中添加不同浓度外源铅(Pb0:背景值,CK; Pb1：175 mg·kg-1+背景值; Pb2：350 mg·kg-1+背景值)，进行小麦—玉米轮作试验。分别于2011—2013年小麦收获季采集耕层（0～20 cm）土壤，分析土壤中铅全量及有效态铅含量的年际变化，以及铅对小麦-玉米轮作模式下土壤有机碳（SOC）、溶解性有机碳（DOC）、微生物量碳（MBC）、碱解氮、速效磷、速效钾含量的影响。结果表明，三年中，施铅处理下土壤中铅全量及有效态铅含量分别下降13.22%和30.65%，总体呈现逐年下降趋势。与对照（CK）相比，Pb1、Pb2处理下SOC平均含量分别下降了16.30%和11.86%；DOC平均含量分别下降了4.05%和7.34%，与土壤铅含量呈现显著负相关关系；低浓度铅污染下土壤微生物商(qM)显著高于对照土壤，微生物量碳含量变化不显著。此外，土壤速效养分的分析显示，土壤碱解氮含量在外源铅加入初期下降明显，且在Pb1处理下碱解氮减少量最大；土壤速效磷含量随土壤铅含量增加而呈现下降趋势；土壤速效钾含量则随土壤铅含量的增加而增加。试验表明，外源铅的加入影响了土壤有机碳的稳定性，对土壤碳、氮循环产生了一定的影响；能够与土壤溶液中的磷酸根生成难溶性盐，与土壤胶体或土壤矿物晶格中的K+发生置换，加大土壤速效养分的流失风险。 |
| 英文摘要: |
| In order to evaluate the response of loess soil to medium-low concentration lead and provide reasonable basis for early warning and controlling of lead pollution, we studied the annual changes of exogenous lead under field condition and the effect of lead pollution on soil organic carbon mineralization and soil available nutrients. Exogenous lead was added into the top layer of the loess soil, the wheat-corn rotation test began in the autumn of 2010. In the wheat season of 2011—2013, the top layer soil (0～20 cm) was collected for analysis of total lead, available lead, soil organic carbon (SOC), dissolubility organic carbon (DOC), microbial biomass carbon (MBC), available N、P and K. The results showed that the total lead and available lead was decreased by 13.22% and 30.65%, respectively in three years, and it had a tendency to decrease by years Compared with the control (CK), Pb pollution was decreased SOC by 16.30% and 11.86% and DOC by 4.05% and 7.34%, in Pb1 and Pb2 levels, respectively, and showed significant negative correlation with soil lead levels. The content of soil microbial quotient (qM) were increased, and there was no significant differences in soil microbial biomass carbon. In addition, the soil available nitrogen content showed a dramatic decline after the exogenous lead addition, with the largest reduction for Pb1. The content of soil available phosphorus was decreased with the increase of soil lead, while the soil available potassium was increased. The study showed that the accumulation and stability of soil organic carbon pool was affected by heavy metal contamination, thus affecting the soil carbon and nitrogen cycling. Lead ions would react with phosphate ions to form indissoluble salts, and the K+ in soil colloids and mineral lattice can be replaced by lead ions, which could pose risk of loss of available nutrients. |
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