土壤氮磷是限制亚热带地区林木生长的关键元素,研究土壤微生物对氮磷养分调控有助于深入揭示人工林土壤肥力维持机制.本研究以3种不同林龄(4、7、11年生)杉木+闽楠复层林为对象,以杉木纯林为对照,分析不同林龄土壤氮磷组分、土壤微生物群落组成和功能变异特征及其相互关系.结果表明:土壤多数磷组分含量随复层林林龄增大呈增加趋势.随林龄增大,活性磷组分中以无机磷增加为主,增幅为9.9％～159.0％,稳定态磷以有机磷增加为主,增幅为7.1％～328.4％.土壤无机和有机氮组分也随复层林林龄增大呈增加趋势,尤其是铵态氮和酸解铵态氮含量增幅较大,分别增加152.9％和80.2％.随林龄增大,细菌和真菌群落组成和功能类群差异显著,部分微生物优势属(如热酸菌属、原隐球菌属、被孢霉属)相对丰度增加,磷溶解和矿化功能基因、氮硝化功能和有氧氨氧化功能基因相对丰度呈增加趋势.真菌功能组成解释了不同磷组分变异的48.9％,纯林转变为复层林可能主要通过改变腐生菌(凋落物和土壤腐生菌)功能类群影响土壤磷组分转化.真菌群落组成变化解释了不同氮组分变异的45.0％,一些重要的属(如原隐球菌属和被孢霉属等)在促进土壤氮转化和积累过程中发挥了关键作用.杉木纯林转化为杉木+闽楠复层林有利于提高土壤氮磷有效性,细菌和真菌在土壤氮磷形态转化过程中发挥了重要作用,尤其是土壤真菌的贡献更大.
Soil nitrogen and phosphorus are two key elements limiting tree growth in subtropical areas.Understand-ing the regulation of soil microorganisms on nitrogen and phosphorus nutrition is beneficial to reveal maintenance mechanism of soil fertility in plantations.We analyzed the characteristics of soil nitrogen and phosphorus fractions,soil microbial community composition and function,and their relationship across three stands of two-layered Cun-ninghumia lanceolata+Phoebe bournei with different ages(4,7 and 11a)and the pure C.lanceolata plantation.The results showed that the contents of most soil phosphorus fractions increased with increasing two-layered stand age.The increase in active phosphorus fractions with increasing stand age was dominated by the inorganic phosphorus(9.9％-159.0％),while the stable phosphorus was dominated by the organic phosphorus(7.1％-328.4％).The content of soil inorganic and organic nitrogen also increased with increasing two-layered stand age,with NH4+-N and acid hydrolyzed ammonium N contents showing the strongest enhancement,by 152.9％and 80.2％,respective-ly.With the increase of stand age,the composition and functional groups of bacterial and fungal communities were significantly different,and the relative abundance of some dominant microbial genera(such as Acidothermus,Sai-tozyma and Mortierella)increased.The relative abundance of phosphorus solubilization and mineralization function genes,nitrogen nitrification function and aerobic ammonia oxidation function genes tended to increase.The func-tional taxa of fungi explained 48.9％variation of different phosphorus fractions.The conversion of pure plantations to two-layered mixed plantation affected soil phosphorus fractions transformation via changing the functional groups of saprophytes(litter saprophytes and soil saprophytes).Changes in fungal community composition explained 45.0％variation of different nitrogen fractions.Some key genera(e.g.,Saitozyma and Mortierella)play a key role in pro-moting soil nitrogen transformation and accumulation.Therefore,the conversion of pure C.lanceolata plantation to two-layered C.lanceolata+P.bournei plantation was conducive to improving soil nitrogen and phosphorus availabil-ity.Bacteria and fungi played important roles in the transformation process of soil nitrogen and phosphorus forms,with greater contribution of soil fungi.
洪宣生;王宗星;徐清福;邱勇斌;成向荣
中国林业科学研究院亚热带林业研究所,杭州 311400浙江省林业技术推广总站,杭州 311400开化县林业局,浙江开化 324300开化县林场,浙江开化 324300
复层林;土壤氮磷;土壤微生物;土壤肥力
two-layered mixed plantation;soil nitrogen and phosphorus;soil microbe;soil fertility
《应用生态学报》 2024 (003)
622-630 / 9
本文由浙江省基础公益研究计划项目(LGN21C160010)和国家自然科学基金项目(32271855)资助.
10.13287/j.1001-9332.202403.002
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