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

发布时间：2018-06-27 09:03

本文选题：外源铅 + 有机碳　；参考：《干旱地区农业研究》2017年04期

【摘要】：以关中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(q M)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。
[Abstract]:The field experiment was carried out with Guanzhong soil as the sample soil sample, and different concentrations of exogenous lead (Pb0: background value, CK, Pb1:175 mg. Kg~ (-1) + background value, Pb2:350 mg. Kg~ (-1) + background value) were added to the soil, and the wheat maize rotation experiment was carried out. The soil of the plough layer (0~20 cm) was collected from the harvest season of 2011 to 2013, and the total amount of lead in the soil was analyzed and the total amount of lead was analyzed. The interannual variation of effective lead content and the effect of lead on soil organic carbon (SOC), dissolved organic carbon (DOC), microbial biomass carbon (MBC), alkali hydrolysable nitrogen, available phosphorus and available potassium in the wheat maize rotation model. The results showed that in the three years, the total lead and effective lead content in soil soil decreased by 13.22% and 30.65% respectively in the three years. Compared with the control (CK), the average content of SOC decreased by 16.30% and 11.86% under the treatment of Pb1 and Pb2, and the average content of DOC decreased by 4.05% and 7.34% respectively. The soil lead content was negatively correlated with the soil lead content, and the soil microorganism merchant (Q M) was significantly higher than the control soil under the low concentration of lead pollution, and the change of microbial biomass carbon content was not significant. In addition, the analysis of soil available nutrients showed that the content of soil alkali hydrolysable nitrogen decreased obviously in the early stage of adding exogenous lead, and the decrease of alkali hydrolysable nitrogen was the largest under the treatment of Pb1, and the content of soil available phosphorus decreased with the increase of soil lead content, and the content of soil available potassium increased with the increase of soil lead content. It affects the stability of soil organic carbon and has a certain influence on soil carbon and nitrogen cycle. It can produce insoluble salts with phosphoric acid roots in soil solution, and replace the K+ in the lattice of soil colloid or soil mineral, and increase the risk of soil quick acting nutrient loss.
【作者单位】：西北农林科技大学资源环境学院农业部西北植物营养与农业环境重点实验室;
【基金】：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)
【分类号】：S153.6;S158

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