杉木老龄林不同地形土壤活性铝形态特征

Characteristics of Soil Active Aluminum Forms in Different Terrains of Old-Growth Plantation of Cunninghamia lanceolata

【目的】通过探究不同地形下杉木老龄林土壤活性铝形态特征,为杉木人工林生态系统铝毒害的精细化治理提供理论依据。【方法】以福建省南平市百年杉木林为研究对象,测定了该林分西南坡、西北坡、山凹部和山洼地共4类地形土壤的pH值、全铝、交换性铝、单聚体羟基铝、酸溶无机铝和腐殖酸铝含量。【结果】该林分土壤pH值范围为4.72~5.09,活性铝主要形态为腐殖酸铝和酸溶无机铝,其含量占全铝含量的25.52%~60.35%。随着土层深度的增加,土壤铝活化程度逐渐降低,土壤pH值、全铝和腐殖酸铝含量不断增加,交换性铝、单聚体羧基铝和酸溶无机铝含量则不断减少。4类地形土壤pH值总体表现为山洼地>西南坡>山凹部>西北坡,全铝含量表现为山凹部>西北坡>山洼地>西南坡,全铝中活性铝所占比例以及交换性铝和酸溶无机铝含量表现为西北坡>西南坡>山凹部>山洼地,腐殖酸铝含量表现为西北坡>山凹部>西南坡>山洼地,单聚体羧基铝含量表现为山凹部>西南坡>西北坡>山洼地,山洼地土壤各形态活性铝含量普遍显著低于西北坡。地形和土层对于腐殖酸铝的含量具有显著的交互作用。主成分分析表明西南坡和山凹部之间、西北坡和山洼地之间土壤活性铝形态分布较为相似;相关性分析表明土壤pH值与交换性铝、腐殖酸铝和酸溶无机铝含量具有显著负相关关系,交换性铝、酸溶无机铝和腐殖酸铝含量三者间具有显著正相关关系。【结论】该杉木老龄林4类地形中以西北坡土壤活性铝积累现象最为明显,其次为西南坡和山凹部,山洼地最低。

【Objective】In this study,the characteristics of soil active aluminum forms in different ter-rains of old-growth plantation of Cunninghamia lanceolata were studied,to provide theoretical basis for the fine management of aluminum toxicity in Cunninghamia lanceolata plantation ecosystem.【Method】This study took a hundred years of Cunninghamia lanceolata plantation in Nanping,Fujian Province as as the research object,and analyzed the pH value,the contents of total aluminum,exchange aluminum,hydroxyl aluminum,acid soluble aluminum and humic acid aluminum in four types of terrain soils in this stand,including southwest slope,northwest slope,corrie and valley.【Result】The soil pH value of this stand ranged from 4.72 to 5.09,and the main forms of active aluminum are humic acid aluminum and acid soluble aluminum,accounting for 25.52%-60.35%of the total aluminum content;The pH value,the contents of total aluminum and humic acid aluminum increased with the increase of soil depth,while the activation degree of soil aluminum and the contents of exchange aluminum,hydroxyl aluminum and acid soluble aluminum were opposite;The order of soil pH value was valley>southwest slope>corrie>northwest slope,the order of the content of total aluminum was corrie>northwest slope>valley>southwest slope,the order of the proportion of active aluminum in total aluminum,the contents of exchange aluminum and acid soluble aluminum was northwest slope>southwest slope>corrie>valley,the order of the content of humic acid aluminum was northwest slope>corrie>southwest slope>valley,the order of the content of hydroxyl aluminum was corrie>northwest slope>southwest slope>valley,and the contents of various active aluminum in the valley were generally significantly lower than that in the northwest slope;Terrain and soil layer have significant interaction on the content of humic acid aluminum;The principal component analysis showed that the distribution of soil active aluminum was similar between the southwest slope and corrie,t and between the northwest slope and valley;The correlation analysis showed that the pH value had a significant or extremely significant negative correlation with the contents of exchangeable aluminum,humic acid aluminum and acid soluble aluminum,and there was a significant positive correlation among the contents of exchangeable aluminum,acid soluble aluminum and humic acid aluminum.【Conclusion】Among the four types of terrains of this Cunninghamia lanceolata old-growth plantation,accumulation of aluminum toxicity was highest in the soil of northwest slope,second in the soil of the southwest slope and corrie,and lowest in the soil of valley.