长白落叶松人工林穿透雨的养分特征

Nutrient Characteristics of Throughfall in Larix olgensis Plantation

生长季,在黑龙江省佳木斯市孟家岗林场,通过不同立地条件、不同龄组长白落叶松(Larix olgensis Henry)人工林林外雨和穿透雨水样的养分分析,对比研究了雨水中养分含量的变化规律。结果表明,降雨通过林冠层后,水化学特性发生了较大变化:幼龄林穿透雨中的铵态氮质量浓度显著高于林外雨(P=0.003),而中、近熟林的铵态氮质量浓度与林外雨之间无显著差异(P分别为0.152、0.471);幼、中和近熟林穿透雨中的硝态氮、全氮和全磷质量浓度与林外雨之间无显著差异(P分别为0.343、0.741、0.937,0.394、0.405、0.616和0.065、0.640、0.162)。铵态氮、硝态氮、全氮和全磷质量浓度方面,不同立地条件之间表现各异:幼、中、近熟林的前3个指标受立地条件的影响均不显著(P分别为0.838、0.408、0.718,0.217、0.427、0.763和0.112、0.690、0.556);全磷质量浓度方面,中龄林不同立地指数之间无显著差异(P=0.319),而幼、近熟林不同立地指数之间存在显著差异(P分别为0.027、0.011):不同立地幼、中和近熟林穿透雨中铵态氮、硝态氮、全氮和全磷质量浓度的平均值分别是11.177、0.748、107.005、1.051mg·L-1,6.847、0.559、107.015、0.646mg·L-1和5.154、0.478、107.082、0.775mg.L-1。穿透雨中的铵态氮、硝态氮、全氮和全磷质量浓度受林龄的影响亦表现不同:穿透雨中铵态氮质量浓度受林龄的影响显著(P<0.001),幼龄林显著高于中、近熟林(P<0.001),中龄林和近熟林之间无显著差异(P=0.149);穿透雨中硝态氮、全氮和全磷质量浓度受林龄的影响均不显著(P为0.294、0.713和0.394),幼龄林和中龄林、中龄林和近熟林、幼龄林和近熟林之间均无显著差异(P分别为0.288、0.628、0.122,0.934、0.499、0.495和0.178、0.603、0.331),硝态氮、全氮和全磷质量浓度的平均值分别是0.563、107.042、0.794mg·L-1。

An experiment was conducted to study the variance in nutrients between rainfall and throughfall in Larix olgensis Henry plantations of different ages grown on different sites at Mengjiagang Forestry Centre in Kiamusze City in growing season. Results showed that the content of ammonium nitrogen （NH＋4—N） in throughfall in young larch plantations was significantly higher than that in rainfall,while there were no significant differences in NH＋4—N content between rainfall and throughfall in middle-aged larch plantations and near-mature larch plantations. No significant differences in contents of nitrate nitrogen （NO-3—N）,total nitrogen （TN）,and total phosphorus （TP） were found between rainfall and throughfall in young,middle-aged and near-mature larch plantations. There were no significant differences in contents of NH＋4—N,NO-3—N and TN between larch plantations on different site conditions,and an insignificant difference in TP content was also observed between middle-aged larch plantations on different site conditions,but significant differences in TP content were found for young and near-mature larch plantations between different site conditions. NH＋4—N content in throughfall in young larch plantation was significantly higher than that in middle-aged and near-mature larch plantations,while there was no significant difference in NH＋4—N content between middle-aged larch plantation and near-mature larch plantation. There were no significant differences in contents of NO-3—N,TN and TP between young,middle-aged,and near-mature larch plantations.