内蒙古贝加尔针茅草原氮素去向的示踪研究  

Fate of Labelled Nitrogen Applied to a Stipa Baicalensis Community of Meadow Steppe in Inner Mongolia Grassland,China

作　　者：乔江[1,2] 赵建宁 李玉洁[1,2] 于雯超[1,2] 杨殿林[1,3,2] 

机构地区：[1]农业部环境保护科研监测所生态农业室,天津300191 [2]沈阳农业大学园艺学院,辽宁沈阳110866 [3]农业部产地环境质量重点实验室/天津市农业环境与农产品安全重点实验室,天津300191

出　　处：《农业环境与发展》2013年第4期13-18,共6页Agro-Environment and Development

基　　金：国家自然科学基金(31170435);"十二五"国家科技支撑计划项目(2012BAD13B07)

摘　　要：采用^15N同位素示踪技术，开展了贝加尔针茅草原氮素去向的研究。结果表明：贝加尔针茅草原植物对标记氮素的回收率为28．36％～37．03％，施氮肥显著影响植物对^15N的回收，随着施氮量的增加，植物地上和地下器官对^15N的回收量均显著提高。凋落物的^15N回收率为2．06％-3．28％。标记氮素的土壤存留率为35．86％～44．32％，大致分布在地表0-40cm的土层范围内；各土层存留的^15N量均随着施氮量的增加而显著升高。标记氮素的当季损失率为19．68％～32．99％。风险／收益比分析表明，在该试验条件下，添加10gN·m^-2的处理风险最低、收益最高，可为草原生态系统的氮素管理提供参考。An important grassland ecosystem management strategy is the application of nitrogen fertilizer, however, the fate of applied nitro- gen is highly correlated with risks and benefits associated with the fertilization of grasslands. The fate of nitrogen tracers applied to Inner Mongolia meadow steppe ecosystem has not been studied previously. We examined the fate of 15N labelled fertilizer in a Stipa baicalensis site at the sample area of the Laboratory of Ecological Agriculture, Ago-Environmental Protection Institute, Ministry of Agriculture. The results showed that after one growing season 28.36%-37.03% of the applied ^15N was recovered in the plant pool.^15N recovered by aboveground and belowground organs significantly increased with increasing nitrogen rates suggesting that nitrogen fertilizer significantly affected the recovery of ^15N by plants. About 2.06%=3.28% of the applied ^15N was recovered in the litter. About 35.86%-44.32% of the labelled nitrogen was re- tained in the soil pool, mostly in the 0-40 cm soil layer. 15N retained by the soil increased significantly with growth in the nitrogen application rate. The loss of ~SN was about 19.68%-32.99% of the labeled nitrogen. Risk/benefit analysis showed that, under the climatic and soil condi- tions prevailing during this experiment, fertilizer application rates of 5 gN＇m-2 and 15 gN＂ m-2 were associated with high risk/benefit ratios, whereas the 10 gN＂ m-2 fertilizer treatment achieved the lowest risk/benefit ratio among the nitrogen rate treatments. These results provide a reference for future grassland ecosystem management strategies.

关 键 词：贝加尔针茅 草原 15N 氮素回收 氮素存留 氮素损失 

分 类 号：S153.6[农业科学—土壤学]