采用分解袋法,在室内设置华北落叶松(Larix principis-rupprechtii)和白桦(Betula platyphylla)叶凋落物混合分解试验,按照不同质量混合比例设置了5种处理,即纯华北落叶松、纯白桦、落桦(1∶1)、落桦(2∶1)、落桦(3∶1)。结果表明:白桦叶凋落物分解速率明显高于纯华北落叶松,华北落叶松和白桦叶凋落物混合分解可以促进华北落叶松叶凋落物的分解,且随着白桦叶凋落物比例的增加,促进作用越来越明显;叶凋落物分解过程中,N,P浓度呈上升趋势,K,C浓度和C/N比呈下降趋势;纯白桦叶凋落物N,K,C释放率大于纯华北落叶松,华北落叶松和白桦叶凋落物混合分解可以促进华北落叶松叶凋落物中N,K,C的释放,对P的释放有一定的抑制作用;叶凋落物分解可以改善土壤pH和养分含量,土壤的pH、有机质、速效N,P,K均有所提高。总体来看,华北落叶松和白桦叶凋落物混合分解对改善土壤养分比纯华北落叶松叶凋落物单独分解效果要好。

Mesh nylonbag method was used to set up indoor mixed litter decomposition tests of Larixprincipis-rupprechtii and Betula platyphylla.Five mixture proportions treatments were set up:pure Larixprincipis-rupprechtii litter,pure Betula platyphylla litter,50% Larixprincipis-rupprechtii litter mixed with 50% Betula platyphylla,66.7% Larixprincipis-rupprechtii litter mixed with 33.3% Betula platyphylla,and 75% Larixprincipis-rupprechtii litter mixed with 25%Betula platyphylla.The results showed that:the litter decomposition rate of Betula platyphylla was significantly higher than that of pure Larixprincipis-rupprechtii,the admixture of Betula platyphylla leaf litter could promote Larixprincipis-rupprechtii litter decomposition,the effect was more obvious as the proportion of Betula platyphylla leaf litter increased;during the whole decomposition process,N and P contents in leaf litter showed an increase tendency,while K,C contentsand C/N ratio presented an opposite tendency;the pure Betula platyphyllalitter release rates of N,K and C were greater than that of pure Larixprincipis-rupprechtii,the admixture of Betula platyphylla leaf litter could promote Larixprincipis-rupprechtii litter release of N,K and C,while the release rate of P was inhibited;leaf litter decomposition can improve soil pH and nutrient content.Soil pH,organic matter,available N,P,K were increased.Overall,mixed litter decomposition of Larixprincipis-rupprechtii and Betula platyphylla can improve the soil nutrient better than the single litter decomposition of Larixprincipis-rupprechtii.