| 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 |
| Key Words: exogenous lead soil organic carbon microbial biomass carbon soil available nutrients |
| Author Name | Affiliation | | DIAO Zhan | College of Resources and Environment, Northwest A＆F University
Ministry of Agriculture Key Laboratory of Plant Nutrition and Agri-environment in Northwest China, Yangling, Shaanxi 712100, China | | LU Jia-long | College of Resources and Environment, Northwest A＆F University
Ministry of Agriculture Key Laboratory of Plant Nutrition and Agri-environment in Northwest China, Yangling, Shaanxi 712100, China | | AN Feng-qiu | College of Resources and Environment, Northwest A＆F University
Ministry of Agriculture Key Laboratory of Plant Nutrition and Agri-environment in Northwest China, Yangling, Shaanxi 712100, China |
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| Abstract: |
| 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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