摘要： 在内蒙古草原对天然羊尿尿斑土壤氮素的变化进行了系统研究,结果表明:随着羊尿的施入,土壤NH₄⁺-N浓度显著升高(p＜0.01),并于第3天达到最大值;施后7 d前(不包括第7天),与对照区相比,施尿区土壤NH₃^--N浓度显著降低(p＜0.05),7 d后,施尿区土壤NH₃^--N浓度显著高于对照区(p＜0.01);羊尿施入35 d前(不包括第35天),土壤NH₄⁺-N浓度显著高于NH₃^--N(p＜0.05),而35 d后,NH₄⁺-N浓度开始低于NH₃^--N,而且差异显著(p＜0.05).施尿后,土壤微生物量氮呈增加趋势,并于第35 d达到最大值,而后开始下降,84 d后又出现升高现象;施尿区0～5 cm和5～10 cm土壤微生物量氮显著高于对照区(p＜0.05),但10～20 cm土壤差异不显著(p＞0.05).施尿后,土壤可溶性有机氮浓度显著升高(p＜0.05),并于第7天达到最大值,而后呈下降趋势,3个取样层次呈一致的变化趋势.施尿区和对照区土壤无机氮与可溶性有机氮、无机氮与微生物量氮存在显著的正相关关系(p＜0.05,p＜0.01),但土壤可溶性有机氮与微生物量氮相关不显著(p＞0.05).

关键词: 内蒙古草原, 羊尿斑块, 土壤氮素, 放牧

Abstract: In Inner Mongolia steppe,the paper studied the changes of soil nitrogen in sheep urine patches,the results indicated:Urine addition increased soil NH₄⁺-N concentrations immediately,but did not increase soil NH₃^--N concentrations significantly(p＜0.05) 7 d.Adding urine significantly(p＜0.01) increased soil NH₄⁺-N concentrations and had the maximum at day 3th.Before 7 d soil NH₃^-N was significantly(p＜0.05) lower than those of the control,but increased significantly(p＜0.01)after 7 d.Soil NH₄⁺-N was significantly(p＜0.05) higher than soil NH₃^--N before 35 d,but soil NH₃^--N was significantly(p＜0.05) higher than soil NH₄⁺-N after 35 d.After urine addition soil microbial biomass N(MBN) increased and had the maximum 35th,soil microbial biomass N was significantly(p＜0.05)higher than the control in layer 0-5 cm and 5-10 cm,but no significant difference in layer 10-20 cm(p＜0.05).Urine addition significantly(p＜0.05) increased extractable soil organic N(ESON) concentrations and had the maximum at 7 d.There were significant positive correlations between soil inorganic nitrogen and soil extractable soil organic N and soil microbial biomass N(p＜0.05,p＜0.01),but no significance between soil extractable,soil organic N and soil microbial biomass N(p＞0.05).

Key words: Inner Mongolia steppe, Sheep urine patch, Soil nitrogen, Grazing

中图分类号: 

• S155.4+7