不同植被条件下土壤团聚体交换性K^+、Na^+的分布特征

Distributions of Exchangeable K^+ and Na^+ in Soil Aggregates under Different Vegetations

采用野外调查与室内分析相结合的方法,研究了岷江上游山地森林干旱河谷区不同植被条件下土壤团聚体交换性K+、Na+的分布特征。结果表明:(1)不同植被条件下土壤团聚体均以>2mm粒径为主,0-10cm和10-20cm土层团聚体的分布均随团聚体粒径的减小呈先增加后降低的趋势。刺槐林地>2mm团聚体含量最高,天然次生林地次之;随着土层深度的增加,不同粒径团聚体分布特征各异。(2)0-10cm土层,随着团聚体粒径的减小,天然次生林地土壤团聚体中交换性K+先增加后降低,其中0.5~0.25mm粒径团聚体中交换性K+含量最高;10-20cm土层,随着团聚体粒径的减小,天然次生林地和岷江柏幼林地土壤团聚体中交换性K+含量呈先增加后降低;其他植被条件下,土壤团聚体交换性K+分布特征各异。(3)0-10cm土层,随着团聚体粒径的减小,退耕岷江柏林地土壤团聚体中交换性Na+含量总体呈现先降低后增加的趋势,其中>5mm粒径团聚体中交换性Na+含量最高;10-20cm土层,随着团聚体粒径的减小,灌木林地土壤团聚体中的交换性Na+先增加后降低,以0.5~0.25mm粒径团聚体中交换性Na+含量最高;退耕岷江柏林地,团聚体中交换性Na+呈先降低后增加的趋势,以>5mm粒径团聚体交换性Na+含量最高;其他植被条件下,土壤团聚体中交换性Na+分布特征各异。

Through field investigation and laboratory analysis,the distributions of exchangeable K^＋and Na^＋in soil aggregates under different vegetations at the ecotone between dry valley and montane forest of the Minjiang River were studied.The results showed that：（1）The contents of soil aggregates were dominated by 〉2mm under different vegetation,and the contents of soil aggregates increased first and then decreased with decreasing particle size of the soil aggregates in the 0-10 cm and 10-20 cm soil layer.The content of 〉2mm aggregate was the highest in Robinia pseudoacacia,natural secondary forest land came the second.The distribution of soil aggregates was different with increasing soil layer.（2）In the 0-10 cm soil layer,content of soil exchangeable K^＋ increased first and then decreased with decreasing particle size of the soil aggregates in natural secondary forest land,and content of soil exchangeable K^＋was the highest in the content of 0.5～0.25 mm aggregate.In the 10-20 cm soil layer,content of soil exchangeable K^＋increased first and then decreased with decreasing particle size of the soil aggregates in natural secondary forest and Minjiang young cypress land.The distributions of soil exchangeable K^＋in soil aggregates were different for the other vegetation.（3）In the 0-10 cm soil layer,content of soil exchangeable Na^＋decreased first and then increased with decreasing particle size of the soil aggregates in the conversion of farmland to Minjiang cypress,and content of soil exchangeable Na^＋was the highest in the content of〉5mm aggregate.In the 10-20 cm soil layer,content of soil exchangeable Na^＋increased first and then decreased with decreasingparticle size of the soil aggregates in the shrub,and content of soil exchangeable Na^＋was the highest in the content of 0.5～0.25 mm aggregate.However,content of soil exchangeable Na^＋decreased first and then increased with decreasing particle size of the soil aggregates in the conversion of farmland to Minjiang cypress,and content of soil exchangeable Na^＋was the highest in the content of 〉5 mm aggregate.The distributions of soil exchangeable Na^＋in soil aggregates were different for the other vegetation.