土壤氮含量对油松针叶碳氮磷计量特征及氮磷重吸收的影响  

Effects of soil nitrogen concentration on needle stoichiometry and N & P resorption of Pinus tabuliformis with stand aging

作　　者：崔爽 姚建忠 张芸香[1,2] 杨屹宇 郭晋平 CUI Shuang;YAO Jianzhong;ZHANG Yunxiang;YANG Yiyu;GUO Jinping(College of Forestry,Shanxi Agricultural University,Taigu,Shanxi 030801,China;Shanxi Provincial Key Laboratory of Cultivation and Research and Development of North Functional Oilseed Species,Taigu,Shanxi 030801,China;Science and Technology Service Center of Shanxi Sangganhe Poplar High Yield Experiment Bureau,Huairen,Shanxi 038300,China)

机构地区：[1]山西农业大学林学院,山西太谷030801 [2]北方功能油料树种培育与研发山西省重点实验室,山西太谷030801 [3]山西桑干河杨树丰产实验局科技服务中心,山西怀仁038300

出　　处：《森林与环境学报》2023年第2期123-131,共9页Journal of Forest and Environment

基　　金：山西农业大学学术恢复科研专项“油松林结构优化与质量精准提升关键技术研究”(2020XSHF34);山西省林业科技创新项目“典型林区油松林近自然经营技术研究”(2018LYCX32)。

摘　　要：为了解土壤氮含量对油松林针叶全碳、全氮、全磷含量和氮磷养分重吸收效率的影响及其随龄级的变化规律,以山西省桑干河杨树丰产林实验局金沙滩林场4个龄级(分别为Ⅱ、Ⅲ、Ⅳ和Ⅴ龄级)油松人工林为研究对象,设置5个施氮水平[CK(0 g·m^(-2)·a^(-1))、N_(1)(5 g·m^(-2)·a^(-1))、N_(2)(10 g·m^(-2)·a^(-1))、N_(3)(15 g·m^(-2)·a^(-1))和N_(4)(20 g·m^(-2)·a^(-1))]的短期氮添加试验。测定了4个龄级对应的5个施氮水平的表层土壤(0~30 cm)氮含量及表层土壤相应的氮含量下成熟针叶和凋落叶全碳、全氮、全磷含量,计算和分析成熟针叶全碳、全氮、全磷含量及其化学计量比,以及相应的氮磷养分重吸收效率。结果表明:各龄级油松针叶全碳、全氮和全磷含量均随土壤氮含量升高表现为先升高后降低的单峰态变化趋势,变化范围分别为509.7~540.5,7.78~12.81和1.97~3.36 g·kg^(-1);碳氮比和碳磷比呈单峰态变化,氮磷比呈直线上升趋势,碳氮比、碳磷比和氮磷比变化范围分别为40.99~65.67、157.06~266.28和2.95~5.12。当土壤氮含量一定时,油松针叶全碳含量随龄级增大而升高,全氮含量在Ⅲ龄级达到最高,全磷含量随龄级增大而降低。计量比除碳氮比外,均随龄级增大而升高。Ⅴ龄级油松针叶氮重吸收效率随着土壤氮含量升高表现较为稳定,其余龄级均表现为持续降低趋势;除Ⅲ龄级的油松针叶磷重吸收效率表现为先升高后降低的变化趋势外,其余龄级均表现为持续升高趋势。油松针叶氮重吸收效率随着龄级的增大表现为升高的趋势,磷重吸收效率随着龄级的增大表现为先降低后升高的趋势。该地区油松人工林生长受氮限制且影响严重,随着土壤氮含量升高和龄级增大,氮限制有所缓解。The aim of this study was to understand the effect of soil nitrogen concentration on the total carbon, nitrogen, and phosphorus(TC, TN, and TP) contents and nutrient reabsorption efficiency of Pinus tabuliformis needles and its change with age. Taking four age classes(Ⅱ,Ⅲ,Ⅳ and Ⅴ) of Pinus tabuliformis in Jintan Forest Farm in Shanxi Province as the research object, five nitrogen application levels were set up in a short-term nitrogen addition experiment: CK(0 g·m^(-2)·a^(-1)), N_(1)(5 g·m^(-2)·a^(-1)), N_(2)(10 g·m^(-2)·a^(-1)), N_(3)(15 g·m^(-2)·a^(-1)), and N_(4)(20 g·m^(-2)·a^(-1)). Subsequently, we measured the nitrogen content of the surface soil(0-30 cm) corresponding to five nitrogen application levels of four age classes and the TC, TN, and TP contents of mature needles and fallen leaves under the corresponding nitrogen content of surface soil. Additionally, the TC, TN, and TP contents of mature needles and their stoichiometric ratios and the corresponding nitrogen and phosphorus nutrient reabsorption efficiency were calculated and analyzed. The TC, TN, and TP contents in the needles of Pinus tabuliformis plantations at all ages showed a single peak trend of first increasing and then decreasing with increasing soil nitrogen content, ranging from 509.7-540.5, 7.78-12.81, and 1.97-3.36 g·kg^(-1), respectively. The C∶N and C∶P ratios showed a single peak change, and the N∶P ratio showed a straight upward trend. The C∶N, C∶P, and N∶P ratios ranged from 40.99-65.67, 157.06-266.28, and 2.95-5.12, respectively. When the soil nitrogen content was fixed, the needle TC content increased with the age class, and the TN content reached the maximum in the third age class, whereas TP content decreased with age. Except for the C∶N ratio, the metering ratio increased with age. The nitrogen reabsorption efficiency of needles in the fifth age class was relatively stable with the increase in the soil nitrogen content, and the remaining age classes showed a continuous decreasing trend. The ph

关 键 词：土壤氮含量 碳氮磷计量特征 养分重吸收效率 针叶 龄级差异 油松人工林 

分 类 号：S757[农业科学—森林经理学]