辽东山区天然次生栎林土壤有机碳含量及其与理化性质的关系

通过对设置在辽东山区本溪市草河口镇和庄河市仙人洞镇两个典型天然次生栎林(Quercus spp.)样地内的土样进行分层(0—10,10—20,20—30,30—40cm)采集和室内分析,研究了0—40cm土层土壤有机碳、全氮、全磷等含量的剖面分布特征,探讨了有机碳与理化性质间的关系。结果表明:土壤有机碳及全氮、全磷、全钾、碱解氮、速效磷、速效钾、阳离子交换量的含量均随土层加深而降低,而土壤容重随土层加深而增加,由t检验和方差分析得知,各指标含量在土层间差异均达到5%显著水平;土壤有机碳与粉粒、pH、全氮、全磷、全钾、碱解氮、速效磷、速效钾、阳离子交换量间均呈显著正相关(r=0.430 9~0.919 0,n=44,P0.01),与土壤容重、砂粒间均呈显著负相关(r=0.388 3~0.670 6,n=44,P0.01),而与黏粒间无显著相关性;由逐步回归分析得知土壤碱解氮、碳氮比、全钾、pH、全氮与有机碳间关系最为紧密。土壤有机碳与其他理化性质间关系密切,且以全氮、碱解氮、碳氮比、全钾和pH对其影响最大;同时,各指标均具有明显的剖面分布规律。

Contents of Soil Organic Carbon and Its Relations with Physicochemical Properties of Secondary Natural Oak Forests in Eastern Mountain Area of Liaoning Province

Based on the sampling (0-10,10-20,20-30 and 30-40 cm) and lab analysis of two representative natural secondary oak forest plots in Liaodong mountain area,which was located in the town of Benxi City River Estuary and the fairy town of Zhuanghe City,the distribution characteristics of soil organic carbon,total nitrogen,and total phosphorus at the depth of 0-40 cm was studied,and the relationship between organic carbon and other physical and chemical properties was discussed.Results showed that soil organic carbon,total nitrogen,total phosphorus,total potassium,available nitrogen,available phosphorus,available potassium and cation exchange capacity tended to decline with the increasing soil depth,howeversoil bulk density generally increased with increasing soil depth.According to the t test and variance analysis,there was a significant difference between the experiment indicators and the soil layer (P＜0.05).Moreover,the content of silt showed a very high positive correlation with the soil organic carbon,pH value,total nitrogen,total phosphorus,total potassium,alkaline hydrolysis nitrogen,available phosphorus,available potassium and cation exchange capacity (r=0.430 9～0.919 0,n=44,P＜0.01).While soil bulk density and the content of sand had a significant negative correlation with soil organic carbon (r=0.388 3～0.670 6,n=44,P＜0.01).But the content of clay had no significant correlation with soil organic carbon.Stepwise regression analysis showed that the relationship between soil available nitrogen,the ratios of carbon to nitrogen,total potassium,pH,total nitrogen and organic carbon was the closest.Overall,there was close relationships between soil organic carbon and other physical and chemical properties,and the total nitrogen,available nitrogen,the ratios of carbon to nitrogen,total potassium and pH had big impact on it.At the same time,each index had obvious profiles distribution.