| 摘要: |
| 【目的】研究氮添加条件下杉木人工林土壤氮有效性、溶解性有机氮(dissolved organic nitrogen，DON)和pH值的变化规律，为氮沉降后杉木人工林土壤肥力管理提供依据。【方法】以安徽省庐江县洋河村林场11年生杉木人工林为研究对象，设定对照（CK，0 kg/(hm2·年)）和氮添加（N,100 kg/(hm2·年)）处理，通过测定2013-2015年连续3年氮添加后土壤不同土层（0～10和10～30 cm）和月份的氮有效性、DON和pH值，研究氮添加条件下土壤氮有效性、DON和pH值的变化特征。【结果】（1）与对照相比，氮添加处理显著促进了土壤有效氮含量的增加(P<0.05)，0～10 cm土层较10～30 cm土层对氮添加的响应更为敏感，且硝态氮（NO-3-N）为杉木人工林土壤有效氮的主要存在形式（64.8%）。（2）与对照相比，氮添加处理显著提高了土壤氮有效性和溶解性有机氮含量(P<0.05)，不同月份氮有效性和溶解性有机氮含量差异显著(P<0.05)，且它们的变化幅度在不同土层存在明显差异。（3）与对照相比，氮添加处理降低了土壤pH值，不同月份pH差异显著(P<0.05)，pH总体上表现为1月和3月较高，7月和9月较低，且随土层深度的增加而上升。（4）与土壤硝态氮和溶解性有机氮含量相比，增加相同程度的铵态氮后，土壤pH值降低的幅度更大，酸化程度更强。【结论】氮添加对杉木人工林土壤氮有效性和溶解性有机氮的增加具有显著促进作用(P<0.05)，且影响程度在月份和土层之间存在显著差异；氮添加降低了土壤pH值，相较硝态氮和溶解性有机氮而言，土壤铵态氮含量的增加更能引起土壤的酸化。 |
| 关键词: 氮添加 杉木人工林 土壤氮有效性 溶解性有机氮 土壤酸化 |
| DOI： |
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| 基金项目:国家“973”计划项目（2012CB416905） |
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| Effects of nitrogen addition on soil nitrogen availability,dissolved organic nitrogen and acidification in a Chinese fir plantation |
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ZHANG Dandan,LI Jing,GUO Qi,et al
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| Abstract: |
| 【Objective】The soil nitrogen availability,dissolved organic nitrogen (DON) and pH were studied in a Chinese fir plantation in Lujiang,Anhui with nitrogen addition to provide basis for soil fertility management after nitrogen deposition.【Method】A 11-year-old Chinese fir plantation in Yanghe village forest farm in Lujiang,Anhui was selected with treatments of control (CK,0 kg/(hm2·a)) and nitrogen addition (N,100 kg/(hm2·a)).Soil nitrogen availability,DON and pH value in different soil layers (0-10 cm and 10-30 cm) and months were investigated after 3-year nitrogen addition (2013-2015) to study their changing characteristics.【Result】(1) Compared with the control, nitrogen addition significantly increased soil available nitrogen content (P<0.05).The response to nitrogen addition was more sensitive in 0-10 cm soil layer than in 10-30 cm soil layer.NO-3-N was the main form of available nitrogen in this Chinese fir plantation (64.8%). (2) Compared with the control,nitrogen addition significantly increased nitrogen availability and DON content,and the difference was significant among months and soil layers (P<0.05).(3) Compared with the control,nitrogen addition reduced soil pH,with significant difference among months (P<0.05).Soil pH was increased with soil depth,and was higher in January and March,and lower in July and September.(4) Compared to the increases of NO-3-N and DON contents, same amount of soil NH+4-N resulted in greater acidification and lower soil pH.【Conclusion】Nitrogen addition significantly promoted soil nitrogen availability and DON,while reduced soil pH.The effects differed between months and soil layers.Compared with NO-3N and DON,NH+4-N increase caused more severe acidification of soil. |
| Key words: nitrogen deposition Chinese fir plantation soil nitrogen availability dissolved organic nitrogen soil acidification |
