| 黄河三角洲区土壤活性氮对盐分含量的响应 |
| 摘要点击 2167 全文点击 1101 投稿时间：2013-10-08 修订日期：2013-12-10 |
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| 中文关键词 土壤盐分 硝态氮 铵态氮 溶解性氮 微生物生物量氮 |
| 英文关键词 soil salinity NO3--N NH4+-N soluble nitrogen microbial biomass nitrogen |
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| 中文摘要 |
| 土壤盐分影响氮素的循环过程，而活性氮组分的变化是表征氮素循环的重要指标. 本研究以黄河三角洲地区的盐渍化土壤为对象，采用室内好气培养法，设置4个NaCl盐分梯度（S1：0.1%；S2：0.5%；S3：0.9%；S4：1.3%），同时添加不同底物（CK：不添加底物；N：添加氯化铵；C：添加葡萄糖；C+N：添加葡萄糖+氯化铵），研究土壤硝态氮（NO3--N）、铵态氮（NH4+-N）、溶解性总氮（TSN）、微生物生物量氮（MBN）对盐分的响应. 结果表明，在45 d的培养期内，CK、N处理低盐（S1、S2）土壤NO3--N含量明显高于高盐（S3、S4），且N处理低盐与高盐的差异更明显. 与CK相比，添加N明显提高低盐土壤NO3--N含量，添加C、C+N明显降低土壤NO3--N，且整个培养期内4个盐分无明显差异. 土壤NH4+-N表现为高盐（S3、S4）明显高于低盐（S1、S2）. 与CK相比，N、C+N处理可明显提高高盐（S3、S4）土壤NH4+-N含量. 土壤MBN表现为低盐高于高盐，N处理尽管提高了低盐土壤TSN含量，但并不能提高MBN，而C、C+N处理可明显提高MBN，且低盐土壤提高的幅度（89.9%~130.9%）明显高于高盐（36.9%~79.5%）. 研究表明土壤盐分影响土壤氮素的转化，高浓度的土壤盐分不利于土壤无机氮的转化及微生物对氮素的吸收，而碳源的添加可削弱盐分的影响，且提高盐碱化土壤微生物的活性，因此在盐碱化土壤中增施有机物质是提高氮素转化的有效措施. |
| 英文摘要 |
| Soil salinity can inhibit the processes of nitrogen cycle, and the active nitrogen is the important indicator to reflect the turnover of nitrogen. A laboratory experiment was conducted to study the effect of soil salinity on the active nitrogen in a soil of the Yellow River Delta incubated aerobically under 25℃ for 45 days. Four levels of salinity (S1: 0.1%, S2: 0.5%, S3: 0.9%, S4: 1.3%) were imposed using NaCl (mass fraction), and glucose with or without NH4Cl were added to the soils. NO3--N,NH4+-N,total soluble nitrogen (TSN) and microbial biomass nitrogen (MBN) were monitored. Results showed that NO3--N was significantly higher in the low salinity soil (S1, S2) than in the high salinity soil (S3, S4) under the control and with NH4Cl addition, and especially the difference was larger with NH4Cl addition. Comparing with the control, NO3--N was increased significantly in S1 and S2.NO3--N was decreased significantly with glucose addition, and there was no difference among the four salinity soils during the whole incubation period. NH4+-N was significantly higher in the high salinity soil (S3, S4) than in the low salinity soil (S1, S2), and it was increased particularly in S4 after day 5.With the addition of NH4Cl, NH4+-N was increased in S3 and S4.MBN was higher in the low salinity soil than in the high salinity soil, and it was not increased with NH4Cl addition, though TSN was increased. With glucose addition, MBN was increased by 89.9%-130.9% in the low salinity soil (S1, S2) and 36.9%-79.5% in the high salinity soil (S3, S4). It was suggested that soil salinity had influence on N transformation, and high salinity inhibited the transformation and assimilation of N by microorganism. The addition of C depressed the effect of salinity, and improved the microbial activity. The application of organic matter is an effective measure to improve N transformation in saline soils. |
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