辽西北半干旱区不同林型土壤团聚体与有机碳的关系

Relationship between Soil Aggregates and Organic Carbon in Different Forest Types in the Semi-arid Areas of Northwestern Liaoning

为更好地研究辽西北半干旱地区人工林土壤团聚体与有机碳及全氮之间的关系,选择该地区主要的人工林类型——樟子松人工林、杨树人工林和油松人工林,通过对其表层土壤(0~10cm)和剖面土壤(10~20,20~30,30~40,40~50cm)进行样品采集和分析,研究不同林型间土壤有机碳、全氮及其各粒级土壤团聚体有机碳、全氮的变化特征。结果表明:樟子松和杨树纯林土壤中有机碳和全氮的变化规律保持一致,都是随着土层深度的增加逐渐减少,而油松纯林中土壤有机碳和全氮含量在0~40cm随着土层深度的增加逐渐减少,而在40~50cm土层中却显著增加;且樟子松和杨树人工林表层土壤养分均高于油松人工林。杨树人工林和油松人工林中的团聚体更多集中在0.053~0.25mm,分别占土壤团聚体总量的63%和62%,而樟子松人工林中0.25~0.053mm和>2mm的团聚体含量均较高,二者约为其土壤团聚体总量的75%。3种林型中,油松人工林土壤团聚体有机碳和全氮含量最高,尤其在0.5~1mm和1~2mm粒级中最为明显,且3种林型中,有机碳和全氮的含量均以<0.053mm、0.5~1mm和1~2mm粒级高于0.053~0.25mm、0.25~0.5mm以及>2mm为主。相关分析表明,3种林型各土层土壤及各粒级土壤团聚体间的有机碳含量和全氮含量均呈极显著的正相关。综上,樟子松和杨树人工林表层土壤养分均高于油松人工林,且樟子松人工林土壤大团聚体含量均高于杨树人工林和油松人工林,这为该地区未来人工林的科学管理提供了参考。

To better understand the relationship between soil aggregate and soil organic carbon and nitrogen of different forest types in the semi-arid areas of northeast Liaoning,this study selected three typical forest types which included Pinus sylvestris var.mongolica plantation,Poplar plantation and Pinus tabulaeformis Plantation in this area,respectively.Both the top-layer soils(0-10 cm)and profile soils(10-20,20-30,30-40,40-50 cm)were collected to analysis its soil aggregates,soil organic carbon and nitrogen contents in this three different plantations.Results showed that the changed trends of soil organic carbon and total nitrogen both in Pinus sylvestris var.mongolica plantation and poplar plantation were similar,and decreased with soil profile depth increased(0-50 cm),while the contents of soil organic carbon and total nitrogen in Pinus tabulaeformis plantation increased suddenly in the lower layer(40-50 cm).Besides,both the contents of top layer soil(0-10 cm)organic carbon and total nitrogen in Pinus sylvestris var.mongolica plantation and poplar plantation were higher than those in the Pinus tabulaeformis plantation.Soil aggregate of 0.053-0.25 mm were much higher both in poplar plantation and Pinus tabulaeformis plantation,and accounting for63%and 62%of total soil aggregates respectively.On the other hand,soil aggregates both of 0.053-0.25 mm and>2 mm were higher in the Pinus sylvestris var.mongolica plantation,and which accounted for 75%of its total soil aggregates.In this three plantations,soil organic carbon and nitrogen of soil aggregates were higher in Pinus tabulaeformis plantation,especially in soil aggregates of 0.5-1 mm and 1-2 mm.Moreover,both organic carbon and nitrogen in soil aggregates of<0.053 mm,0.5-1 mm and1-2 mm were higher than those in soil aggregates of 0.053-0.25 mm,0.25-0.5 mm and>2 mm.The correlation analysis showed that there were significant positively correlation-ships among soil aggregates,and its organic carbon,nitrogen.Generally,both organic carbon and total nitrogen of top layer soils were higher in Pinus sylvestris var.mongolica plantation and poplar plantation,and the contents of soil macro-aggregates in Pinus sylvestris var.mongolica plantation were higher than those in poplar plantation and Pinus tabulaeformis plantation.This study would be a good basis for the future scientific management of plantations in this semiarid areas.