摘要
【目的】分析不同林龄杉木林土壤中的磷素形态变化特征,探讨林龄与不同分类水平解磷菌种类及相对丰度的联系,为人工林土壤磷素的有效利用和可持续经营提供参考。【方法】在福建南平选取5个林龄(4、15、24、43、100年)杉木人工林,用改进Hedley磷素分级法测定0~20 cm土壤中不同分级磷素含量,并采用高通量测序技术对PCR扩增的phoD基因进行测定,得到不同分类水平上解磷菌的相对丰度。【结果】在同一林龄杉木林中,总体上不同分级磷素含量大小依次是Residual-P>NaOH-P>NaHCO_(3)-P>H_(2)O-P>HCl-P。土壤中H_(2)O-IP含量随林龄增加而显著升高(P<0.05),NaHCO_(3)-IP含量随林龄增加先升后降,在43年时最大。随林龄增加,土壤NaOH-P含量波动明显,表现为24年>100年>43年>4年>15年。有机磷总量整体呈上升趋势,随林龄变化表现为100年>24年>43年>15年>4年。随林龄增加,杉木人工林土壤中活性磷含量逐渐升高,杉木幼龄林、中龄林、近熟林的土壤磷素活性表现为稳定态磷>中等活性磷>活性磷,过熟林的磷素活性表现为稳定态磷>活性磷>中等活性磷。杉木林土壤的解磷菌丰富度随林龄增加总体表现为43年>100年>24年>15年>4年,解磷菌种群多样性总体表现为43年>100年>15年>24年>4年。OTU韦恩图和PCoA分析表明,15年和24年土壤中解磷菌结构和多样性相近,43年杉木林土壤包含的解磷菌类群最丰富,且独特性最明显。4年杉木林解磷菌类群数目最少。在门分类水平上,土壤中变形菌门含量最高,其次是异常球菌-栖热菌门和放线菌门;在属分类水平上,优势类群主要有慢生根瘤菌属、Pseudolabrys、假单胞菌属、异常球菌属等;冗余分析表明,土壤NaHCO_(3)-IP与厚壁菌门相对含量呈显著正相关,NaOH-IP与放线菌门、芽单胞菌门等呈显著负相关;HCl-OP与酸杆菌门呈显著负相关,H_(2)O-OP、NaHCO_(3)-IP与慢生根瘤菌属呈显著负相关。【结论】随林龄增加,杉木人工林土壤中不同形态的磷素含量变化明显,土壤活性磷含量不断提高,近熟林和过熟林土壤的潜在供磷能力高于幼龄林和中林龄;土壤理化性质的改变影响了土壤微生物活性,解磷菌的丰富度和多样性增加可能在一定程度上提高了杉木人工林土壤磷素的有效性。
【Objective】This article aims to analyze the variation of phosphorus fractions in the soil of Chinese fir plantations with different stand ages,and to explore the internal relationship between the stand age and the species and relative contents of phosphorus solubilizing microbes at different classification levels,so as to provide reference for the effective use of soil phosphorus and sustainable management of plantations.【Method】Five Chinese fir plantations of different ages(4-,15-,24-,43-and 100-year-old)were selected in Nanping,Fujian.The modified Hedley phosphorus grading method was used to determine the phosphorus content of different grades in 0-20 cm soil layer.High-throughput sequencing technology was used to determine the phoD gene amplified by PCR to obtain the relative abundance of phosphorus solubilizing microbes at different classification levels.【Result】Overall,at the same age of Chinese fir plantations,the phosphorus content of different grades was Residual-P>NaOH-P>NaHCO_(3)-P>H_(2)O-P>HCl-P.The content of H_(2)O-IP increased significantly with the increase of stand age(P<0.05),and the content of NaHCO_(3)-IP increased and then decreased with the increase of the stand age,reaching the maximum in 43-year-old stands.As the stand age increased,the soil NaOH-P content fluctuated significantly,showing 24 year-old stands>100-year-old stands>43-year-old stands>4-year-old stands>15-year-old stands.The total amount of organic phosphorus showed an upward trend as a whole,in the order of 100-year-old stands>24-year-old stands>43-year-old stands>15-year-old stands>4-year-old stands.With the increase of stand age,the content of labile phosphorus in the soil of Chinese fir plantation gradually increased.The soil phosphorus activity in young forest,middle-aged forest,and near-mature forest of Chinese fir showed that stable phosphorus>moderately labile phosphorus>labile phosphorus.The phosphorus activity of over-mature forest showed the order of stable phosphorus>labile phosphorus>moderately labile phosphorus.Overall,the abundance of phosphorus solubilizing microbes in the soil of Chinese fir forest showed 43-year-old stands>100-year-old stands>24-year-old stands>15-year-old stands>4-year-old stands,and the diversity showed 43-year-old stands>100-year-old stands>15-year-old stands>24-year-old stands>4-year-old stands.OTU Venn diagram and PCoA analysis showed that the structure and diversity of phosphorus solubilizing microbes in 15-year-old stands and 24-year-old stands were similar.The soil of 43-year-old Chinese fir plantation contained the most abundant and unique groups of phosphorus solubilizing microbes.The number of phosphorus solubilizing microbes in 4-year-old stands Chinese fir forest was the least.At the phylum classification level,the content of Proteobacteria in the soil was the highest,followed by Deinococcus-Thermus and Actinobacteria.At the genus classification level,the dominant groups were mainly Bradyrhizobium,Pseudolabrys,Pseudomonas,Deinococcus,etc.Redundancy analysis showed that there was a significantly positive correlation between relative contents of soil NaHCO_(3)-IP and Firmicutes,and a significant negative correlation between NaOH-IP and Actinobacteria,Gemmatimonadetes,etc.HCl-OP was significantly negatively correlated with Acidobacteria,while H_(2)O-OP,and NaHCO_(3)-IP were significantly negatively correlated with Bradyrhizobium.【Conclusion】With the increase of stand age,the content of different forms of phosphorus in the soil of Chinese fir plantation varies significantly,and the level of soil labile phosphorus continuously increases.The potential supply capacity of the soil in near-mature and over-mature forests is higher than that of young and middle-aged forests.The changes in soil chemical properties affect soil microbial activity,and the increase in the abundance and diversity of phosphorus solubilizing microbes may increase the availability of soil phosphorus in Chinese fir plantations to a certain extent.
作者
王淑真
梁晶晶
包明琢
潘菲
周垂帆
Wang Shuzhen;Liang Jingjing;Bao Mingzhuo;Pan Fei;Zhou Chuifan(College of Forestry, Fujian Agriculture and Forestry University Fujian Provincial Colleges and University Engineering Research Center of Plantation Sustainable Management, Fuzhou 350002)
出处
《林业科学》
EI
CAS
CSCD
北大核心
2022年第2期58-69,共12页
Scientia Silvae Sinicae
基金
国家自然科学基金项目(32071746)
福建省自然科学基金项目(2020J01520)
福建林业厅科技推广项目(2020TG20)
福建农林大学林学高峰学科建设项目(71201800727)。
关键词
杉木人工林
林龄
磷形态
解磷菌
Chinese fir plantation
stand age
phosphorus fractions
phosphorus solubilizing microbes
