秦岭西部中幼龄华北落叶松林地土壤养分与酶活性特征研究  

Characteristics of soil nutrients and enzyme activities in young and middle aged Larix principis- rupprechtii plantation in western Qinling Mountains

作　　者：王伟东[1] 王渭玲[1] 徐福利[2,3] 于钦民[2] 马惠玲[1] 

机构地区：[1]西北农林科技大学生命科学学院,陕西杨凌712100 [2]西北农林科技大学资环学院,陕西杨凌712100 [3]中国科学院水利部水土保持研究所,陕西杨凌712100

出　　处：《植物营养与肥料学报》2015年第4期1032-1039,共8页Journal of Plant Nutrition and Fertilizers

基　　金：国家重点基础研究发展计划"973计划"(2012CB416902)项目资助

摘　　要：【目的】作为最重要的速生造林树种,50多年前华北落叶松就被引入陕西并造林,引种初期华北落叶松生长良好,而近年来生长势明显下降,地力衰退问题也日益受到关注。本文研究了秦岭西部中幼龄华北落叶松林地土壤养分与酶活性特征,以期为华北落叶松幼龄期人工林的合理经营、中幼龄林地土壤生态系统结构、功能及其可持续利用提供科学依据。【方法】本试验选取立地条件基本一致的5 a、10 a和20 a的华北落叶松人工林地,每个样地设置20 m×20 m的标准地,用土钻在每个标准地沿＂S＂型采集5个点的0—20 cm、20—40 cm和40—60 cm的土样,各层混均,用四分法取样,分析不同林龄华北落叶松人工林地土壤剖面的p H值、有机质及氮、磷养分和酶活性。【结果】研究结果表明,土壤p H值在5 a林地随土壤深度的增加逐渐升高,而在10 a和20 a林地表现为先降低后显著升高（P〈0.05）,不同林龄林地0—20 cm土层的p H值变化范围为6.21-6.71,表现为10 a〉5 a〉20 a;40—60cm和20—40 cm土层均表现为5 a〉10 a〉20 a。不同林龄林地的表层（0—20 cm）土壤有机质含量变化范围为18.68-25.89 g/kg,均显著高于下层（20—40 cm和40—60 cm）土壤,随着林龄的增加没有明显的变化趋势。土壤全氮、硝态氮、铵态氮和速效磷含量随着土壤深度的增加呈明显下降的趋势（P〈0.05）,而在0—20 cm土层中,20 a林地的氮含量显著高于5 a和10 a林地的（P〈0.05）,10 a林地的速效磷含量最高。不同林龄的土壤蔗糖酶、脲酶和磷酸酶活性在0—20 cm土层显著高于20—40 cm和40—60 cm土层（P〈0.05）,过氧化氢酶活性却呈相反的变化趋势。0—20 cm土层,不同林龄林地的蔗糖酶和脲酶活性表现为10 a〉5 a〉20 a,磷酸酶和过氧化氢酶活性在20 a林地土壤中最大,不同林龄林地土壤蔗糖酶、脲酶、磷酸酶和过氧化氢酶活性的变化范围分别为【Objectives】As one of the most important fast- growing afforestation tree species,Larix principis-rupprechtii has been introduced to Shaanxi Province fifty years ago. They grew well in early age,but with the age increased,the growth rate obviously slowed down. So,we studied the characteristics of soil nutrients and enzyme activities in young and middle aged Larix principis- rupprechtii plantation in western Qinling Mountains.【Methods】We chose three different aged Larix principis- rupprechtii（ 5 a,10 a and 20 a） plantations in the Nantan Nursery Garden of Taibai in Shannxi Province as the experimental sites,and established 20 × 20 m plot in each age stand plantation in 2012. In each plot,soil samples were collected at three depths（ 0-20 cm,20-40 cm,and 40-60 cm） in five randomly located points following ＂S＂. Using these samples,we examined soil chemical properties（ p H, organic matter, total N, ammonium N, nitrate N and available P） and enzyme activities（ phosphatase,urease,invertase,and catalase） in the different age of plantations.【Results】With the soil depth increased,the soil p H values are increased in 5 years ＇ plantations,but decreased first and then significantly increased（ P〈0. 05） in 10 and 20 years＇ plantations. The soil p H range from 6. 09 to 6. 71,in order of 10 a 5a 20 a in 0-20 cm layer,and 5 a 10 a 20 a in 20-40 cm and 40-60 cm layers. The contents of soil organic matter in 0-20 cm layer range from 18. 68 to 25. 89 g / kg,significantly higher than in 20-40 cm and 40- 60 cm layers,and keep constant as the planting age increased. There are significant reductions（ P〈0. 05） in soil total N,ammonium N,nitrate N and available P nutrients as the soil depth increased. In 0-20 cm layer,the contents of soil total N,ammonium N and nitrate N in 20 years＇ plantations are significantly higher（ P〈0. 05） than those in other- aged plantations. The soil available P in 10 years ＇ plantations is highest. The activities of soil invertase,urease and phosphatase

关 键 词：华北落叶松 林龄 土壤养分 土壤酶活性 

分 类 号：S791.22[农业科学—林木遗传育种]