亚美马褂木和杉木人工纯林土壤碳氮积累特征的比较研究

Comparison of Soil Carbon and Nitrogen Accumulation Characteristics Between Liriodendron sino-americanum and Cunninghamia lanceolata Forest

【目的】比较亚美马褂木(Liriodendron sino-americanum)和杉木(Cunninghamia lanceolata)人工林林地土壤碳氮积累与分布格局差异,建立其与土壤理化性状的联系,为将来亚美马褂木的大面积推广造林提供理论依据。【方法】以同期营造的本地当家树种杉木人工纯林为对照,对江西省余江县亚美马褂木17年龄人工纯林林地土壤分层取样并运回实验室进行测定。对两种人工纯林林地土壤碳、氮储量和分布格局及理化性状进行测定,并在此基础上借助Pearson相关性分析探讨亚美马褂木人工纯林林地土壤碳、氮积累与土壤理化性状的相关性。【结果】亚美马褂人工纯林林地0~60 cm土层土壤碳、氮含量和储量均随着土壤深度增加而持续降低,其中0~20 cm土层土壤碳、氮储量分别占48.58%和58.44%,杉木人工纯林具有相似的分布趋势,其中0~20 cm土层土壤碳、氮储量分别占72.10%和76.99%。亚美马褂木人工纯林林地0~60 cm土层土壤碳储量为73.84 t/hm^(2),略高于杉木人工纯林的69.35 t/hm^(2),而氮储量为3.08 t/hm^(2),略低于杉木人工纯林的4.35 t/hm^(2),亚美马褂木和杉木人工纯林林地土壤碳、氮储量的差异均没有达到显著水平。亚美马褂木人工纯林林地0~60 cm土层土壤pH随着土壤深度增加而增加,并且显著高于杉木人工纯林,而其他土壤理化性状在两种森林类型间差异不显著。Pearson相关性分析结果表明亚美马褂木人工纯林林地土壤碳、氮含量均与土壤碱解氮和速效钾高度正相关(|r|≥0.8),并达到极显著水平(P<0.01)。【结论】亚美马褂木和杉木人工纯林林地0~60 cm土壤碳、氮储量差异不明显,但是分布格局差异显著。另外,亚美马褂木生长快速、枝叶繁茂,对氮和钾的需求量较大,所以合理的施肥能促进亚美马褂木的生长并促进土壤碳、氮储量的增加,特别是氮肥和钾肥。

[Objective]Soil carbon,nitrogen accumulation and their distribution patterns were compared between Liriodendron sino-americanum and Cunninghamia lanceolata forest,and their relationships with soil physicochemical properties were established,thus providing theoretical basis for afforestation with Liriodendron sino-americanum in large scale.[Method]Taking the pure C.lanceolata plantation constructed simutaneously as the control,the soil samples in 0-60 cm soil layer of 17 a plantation of L.sino-americanum in Yujiang county of Jiangxi province were collected layer-by-layer and transported to laboratory for analysis.The soil carbon,nitrogen storage and the distribution patterns of the two plantations were investigated,the soil physicochemical properties were also determined in the laboratory,and the correlations between soil carbon,nitrogen accumulation and soil physicochemical property were discussed.[Result]Soil carbon and nitrogen content in soil layer of0-60 cm of L.sino-americanum plantation decreased continuously with the increase of soil depth,the soil carbon and nitrogen storage in soil layer of 0-20 cm accounted for about 48.58%and 58.44%of that of 0-60 soil layer,respectively.Soil carbon and nitrogen content and their changes with soil depth in C.lanceolate plantation exhibited a similar trend as that in L.sino-americanum plantation,and the soil carbon and nitrogen storage in soil layer of 0-20 cm accounted for about 72.10%and 76.99%of that of 0-60 soil layer,respectively.The soil carbon storage in soil layer of 0-60 cm of L.sino-americanum plantation was 73.84 t/hm^(2),which was slightly higher than that of C.lanceolate plantation(69.35 t/hm^(2)),and the soil nitrogen storage of L.sino-americanum plantation was 3.08 t/hm^(2),which was slightly lower than that of C.lanceolate plantation(4.35 t/hm^(2)).The differences of the soil carbon and nitrogen storage in soil layer of 0-60 cm between L.sino-americanum and C.lanceolate plantation was not significant.Soil pH in soil layer of 0-60 cm of L.sino-americanum plantation increased with the increase of soil depth,and it was significantly higher than that of C.lanceolate plantation,other soil physicochemical properties exhibited no significant difference between the two tree plantations.Pearson correlation analysis showed that the soil carbon and nitrogen content in soil layer of 0-60 cm of L.sino-americanum plantation exhibited highly significant(P<0.01)positive correlations with the soil alkaline nitrogen and available potassium(r≥0.8).[Conclusion]The differences of soil carbon and nitrogen storage in soil layer of 0-60 cm between L.sino-americanum and C.lanceolate plantation was not significant,but their distribution patterns between the two tree plantations differed significantly.In addition,L.sino-americanum grew rapidly with luxuriant foliage,which required a large amont of nitrogen and potassium supply,hence adequate fertilization could promote the growth of L.sino-americanum and the accumulation of the carbon and nitrogen storage in the soil of L.sino-americanum plantation,especially the application of nitrogen and potassium fertilizers.