基于不同林分类型下土壤碳氮储量垂直分布

以辽东大伙房水库周边防护林典型林分针阔混交林(落叶松-油松-刺槐混交林)、油松林、落叶松林、刺槐林为研究对象,对其土壤养分含量进行测定,研究了不同林分土壤剖面上有机碳、全氮、有机碳储量的分布规律。结果表明:随着土层深度的增大,4种林分的土壤有机碳、全氮含量均逐渐降低;4种林分土壤剖面有机碳含量大小顺序为落叶松林(24.16g/kg)刺槐林(23.07g/kg)针阔混交林(16.06g/kg)油松林(15.76g/kg);全氮含量大小顺序为刺槐林(5.23g/kg)落叶松林(4.57g/kg)油松林(3.45g/kg)针阔混交林(2.42g/kg);C/N平均值大小顺序为落叶松林(7.36)针阔混交林(6.51)油松林(4.67)刺槐林(4.57);4个林分0-40cm土层的有机碳储量大小为落叶松林(112.94t/hm~2)刺槐林(107.40t/hm~2)针阔混交林(105.42t/hm~2)油松林(89.89t/hm~2);4种林分土壤pH无明显差别,各土层土壤pH随土层深度增加而增大;4种林分土壤容重由高到低顺序依次为针阔混交林(1.73g/cm~3)油松(1.65g/cm~3)落叶松(1.64g/cm~3)刺槐(1.56g/cm~3)。4个林分土壤有机碳含量与土壤全氮含量互相间均存在极显著正相关关系,土壤有机碳、全氮含量与C/N之间则没有明显相关关系;在针阔混交林中,土壤容重、土壤全氮含量和土壤pH与土壤有机碳之间存在线性数量关系,而其他纯林则没有这种关系。

Vertical Distributions of Soil Carbon and Nitrogen Reserves in Different Forests

The typical shelter forests around Dahuofang Reservoir in Liaodong were taken as research object in this study, including the coniferous and broad-leave mixed forest (larch-pine-locust mixed forest), larch, pine and locust. Soil nutrients were determined to study the distribution characteristics of organic carbon, total nitrogen and organic carbon in soil profiles under different forest stands. The results showed that with the increase of soil depth, the soil organic carbon and total nitrogen contents decreased gradually in the studied four forests. The order of soil profile organic carbon contents in the four forests was:larch forest (24.16 g/kg) > locust forest (23.07 g/kg) > coniferous and broad-leave mixed forest (16.06 g/kg) > pine forest (15.76 g/kg). The order of total nitrogen contents was:locust forest (5.23 g/kg) > larch forest (4.57 g/kg) > pine forest(3.45g/kg) > coniferous and broad-keave mixed forest(2.42g/kg); The order of average C/N was:Larch forest(7.36) > coniferous and borad-leave mixed forest(6.51) > pine forest(4.67)>locust forest(4.57). The organic carbon storages of 0-40 cm soil layer in four forest stands:Larch forest (112.94 t/hm²) > locust forest (107.40 t/hm²) > coniferous and broad-leave mixed forest (105.42 t/hm²) > pine forest (89.89 t/hm²). There was no significant difference in soil pH between different forests. And the soil pH of each soil layer increased with the increasing soil depth. The soil bulk densities of the four forests was in descending order:Coniferous and broad-leave mixed forest (1.73 g/cm³) > pine forest (1.65 g/cm³) > larch forest (1.64 g/cm³) > locust forest (1.56 g/cm³). There was a significant positive correlation between soil organic carbon contents and soil total nitrogen contents in the four forest stands, while no significant correlations occurred between soil organic carbon and total nitrogen content and C/N. In the coniferous and broad-leave mixed forest stand, a significant linear relationship occurred between soil bulk density, soil total nitrogen content and soil pH with soil organic carbon, while no significances in other pure forest stands.