喀斯特原生乔木林和次生林土壤氮矿化特征

发布时间：2018-03-31 11:52

本文选题：喀斯特森林　切入点：群落类型　出处：《南京林业大学学报(自然科学版)》2017年05期

【摘要】：【目的】探究喀斯特森林土壤氮矿化特征及供氮能力。【方法】以贵州喀斯特原生乔木林和次生林为研究对象,采用树脂芯法,原位连续培养测定土壤氮矿化/硝化动态特征。【结果】(1)喀斯特原生乔木林和次生林土壤无机氮含量随培养时间延长存在明显的变化,NH_4~+-N含量呈先增加后减少再增加趋势,NO-3-N含量表现为总体增加趋势。NH_4~+-N是土壤有效氮的主要存在形式,其含量占土壤无机氮的84.57%~94.31%。(2)两演替群落土壤氮矿化速率呈"V"形变化,范围分别为-0.43~0.97 mg/(kg·d)和-0.91~1.43 mg/(kg·d);硝化速率呈波动上升趋势,范围分别为0.21~0.49 mg/(kg·d)和0.03~0.31 mg/(kg·d)。(3)原生乔木林土壤无机氮含量、矿化速率、氨化速率和硝化速率均高于次生林。(4)原生乔木林土壤氮全年净矿化总量170.82 kg/(hm~2·a),是次生林的2.48倍,两种林分土壤净硝化氮分别占净矿化氮的95%和100%。【结论】喀斯特森林土壤供氮能力较强,但土壤氮矿化过程中氮硝化占主导,表明土壤中植物可利用的氮素易于淋溶或挥发损失。
[Abstract]:[objective] to study the characteristics of nitrogen mineralization and nitrogen supply ability of karst forest soil. [methods] the primary tree forest and secondary forest of Guizhou karst forest were studied, and the resin core method was used. The dynamic characteristics of soil nitrogen mineralization / nitrification were determined by in situ continuous culture. [results] [results] the contents of inorganic nitrogen in the soil of primary tree forest and secondary forest of karst forest changed obviously with the increase of culture time. NH4 ~ -N content increased first and then decreased and then increased. The general increasing trend of NO-3-N content was that NH4- N was the main form of soil available nitrogen. The soil nitrogen mineralization rate of the succession community showed a "V" shape, ranging from -0.43 to 0.97 mg/(kg / d and -0.911 / 1.43 mg/(kg / dN, respectively, and the nitrification rate showed a fluctuating upward trend, ranging from 0.21 to 0.49 mg/(kg / d and 0.030.31 mg/(kg / d ~ (3), respectively, from 84.57 to 94.31 mg/(kg / d ~ (2)) of soil inorganic nitrogen in two succession communities, respectively, and the contents of inorganic nitrogen in the soil of Arbor forest were in the range of -0.43 ~ (0.97 mg/(kg / d) and -0.911 ~ (1.43) mg/(kg / d ~ (3), respectively. The mineralization rate, ammoniation rate and nitrification rate were higher than that in the secondary forest. The total net mineralization amount of soil nitrogen in the native Arbor forest was 170.82 kg/(hm~2 / a per year, which was 2.48 times of that in the secondary forest. [conclusion] the nitrogen supply ability of karst forest soil is stronger, but nitrogen nitrification dominates in the process of soil nitrogen mineralization, which indicates that the available nitrogen in soil is easy to be leached or volatilized.
【作者单位】：贵州省林业科学研究院;
【基金】：贵州省林业厅青年人才基金项目(黔林科合J字[2014]09号,黔林科合J字[2015]14号) 贵州省重大基础研究项目(黔科合JZ字[2014]200212) 贵州森林生态效益监测与评价科技创新人才团队项目(黔科合人才团队[2014]4004号) 贵州省林业科学研究院院士工作站项目(黔科合院士站[2014]4006)
【分类号】：S714.2

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