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以小兴安岭地区红松混交林(椴树红松混交林、云冷杉红松混交林和枫桦红松混交林)大、中、小3个林隙为研究对象,对林隙和郁闭林分土壤铵态氮(NH4+-N)、硝态氮(NO3--N)、可溶性全氮(TSN)、可溶性有机氮(SON)、微生物氮(MBN)和全氮(TN)含量进行分析,探讨不同混交林林隙中土壤氮形态特征。结果表明:林隙和郁闭林分土壤以有机氮为主,占TN 98%以上。林隙中土壤NO3--N含量高于NH4+-N含量;SON含量高于NH4+-N和NO3--N含量。红松混交林中土壤NH4+-N、NO3--N、SON和MBN含量在大、小林隙之间以及林隙与郁闭林分之间差异显著,尤其是MBN含量表现为郁闭林分>小林隙>中林隙>大林隙,与林隙面积呈极显著负相关;3个林型中NO3--N/TN和MBN/TN随着林隙面积增大而减小;椴树红松混交林和云冷杉红松混交林林隙中NH4+-N/TN、TSN/TN和SON/TN随林隙面积增大而减小,枫桦红松混交林林隙中随林隙面积增大而增大。林隙和郁闭林分中土壤TSN与SON均呈现极显著正相关;林隙土壤NH4+-N与NO3--N和MBN呈显著相关,但在郁闭林中未表现出此关系。
Taking Pinus koraiensis mixed forest (mixed forest of Pinus koraiensis, mixed forest of Pinus firmanii and Pinus koraiensis - Korean pine mixed forest) in Xiaoxing’anling area as study object, The contents of NH4 + -N, NO3 - N, TSN, SON, MBN and TN in soil were analyzed. Soil nitrogen forms in different gaps of mixed forests. The results showed that the main soil organic nitrogen was in the gap and canopy stand, accounting for more than 98% of TN. The content of NO3 - N in the soil was higher than that of NH4 + -N in the gaps. The content of SON was higher than that in NH4 + -N and NO3 - N. The contents of soil NH4 + -N, NO3 - N, SON and MBN in the mixed forest of Pinus koraiensis and Pinus koraiensis were significantly different among the large and small gaps and between the gap and the stand of canopy, especially the content of MBN in the stand> Small gap> medium gap> large gap, and the gap area was extremely significant negative correlation; NO3 - N / TN and MBN / TN of three forest types decreased with the increase of gap area; The NH4 + -N / TN, TSN / TN and SON / TN in gaps of mixed forests of Pinus koraiensis and mixed forest decreased with the increase of gap area, Increase. There was a significant positive correlation between soil TSN and SON in the gaps and canyon forests. NH4 + -N in the gaps was significantly correlated with NO3 - N and MBN, but not in the canopy forests.