日照市茶园土壤活性铝形态特征及影响因素

Distribution of Soil Active Aluminum Forms and Influencing Factors in Tea Garden of Rizhao City

茶树是典型的聚铝型植物,茶园土壤中过量的铝会抑制茶树根茎叶的生长,降低茶叶品质。本研究以日照市茶叶主产区的110个表层(0~20 cm)土壤样品为试材,采用连续浸提法研究日照市茶园土壤铝的形态分布特征及影响因素。结果表明:日照市茶园土壤全铝(T-Al)含量范围为9.82~28.99 g/kg,土壤活性铝(Tac-Al)总量为920.50~4007.23 mg/kg,平均占全铝含量的12.52%;土壤各形态活性铝含量由高到低依次为铝的水合氧化物和氢氧化物(Hy-Al)>腐殖酸铝(Ha-Al)>交换态铝(Ex-Al)>有机结合态铝(Or-Al)>无机吸附态铝(In-Al),其中Hy-Al与Ha-Al占活性铝总量的90%以上,是日照市茶园土壤活性铝的主要形态;与未植茶地相比,茶园土壤全铝和各形态铝含量均有不同程度增加;T-Al含量主要受母质和成土过程影响;Ex-Al和Or-Al与土壤pH值及有机质含量呈极显著相关,随土壤pH的降低和有机质的增加而增加;Hy-Al及Ha-Al与游离铁显极著正相关,反映了成土作用强度的影响;随植茶年限增加,T-Al和Ex-Al含量呈先增加后降低趋势,Or-Al、Hy-Al与Ha-Al呈现波动变化趋势,In-Al变化不大。

Tea plant is a typical Aluminum hyperaccumulator.Excessive Aluminum has negative effects on the growth and quality of tea plant.In this study,110 surface soil samples(0~20 cm)were used to study the distribution of soil active aluminum forms and influencing factors in tea garden soil of Rizhao City,based on continuous extraction method.The results showed that the content of total aluminum and the content of active aluminum varied from 9.82 to 28.99 g×kg^(-1) and from 920.50 to 4007.23 g×kg^(-1),accounting for 12.52%of total Aluminum on average.The order of active aluminum content was Hy-Al>Ha-Al>Ex-Al>Or-Al>In-Al.Hy-Al and Ha-Al were the main active aluminum forms in tea garden soil in Rizhao City,accounting for more than 90%of the total content of active aluminum.The contents of total and active aluminum were higher in tea garden soil than unplanted tea plant soil.T-Al content is mainly affected by parent material and soil-forming processes.Ex-Al and Or-Al were significantly correlated with soil pH and organic matter content,and increased with the decrease of soil pH and the increase of organic matter content.Hy-Al and Ha-Al were significantly positively correlated with free iron,reflecting the influence of the degree of soil development.With the increase of tea planting years,the contents of T-Al and Ex-Al increased first and then decreased,Or-Al,Hy-Al and Ha-Al showed a fluctuating trend,while In-Al showed little change.