不同林龄橡胶(Hevea brasiliensis)林土壤微生物群落和磷组分的变化

Abstract

PDF HTML阅读 XML下载 导出引用 引用提醒 不同林龄橡胶(Hevea brasiliensis)林土壤微生物群落和磷组分的变化 DOI: 10.5846/stxb201705020803 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金（31640014）；中央级公益性科研院所基本科研业务费专项（17CXTD-04，2015hzs1J012）；海南省自然科学基金（317235） Effects of rubber (Hevea brasiliensis) plantations on soil phosphorus fractions and microbial community composition Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:橡胶林是我国热带地区重要的经济林，而土壤磷是热带地区植物生长的重要限制因子之一，理解土壤磷转化机理对于生态系统的磷管理和可持续发展具有重要意义。因此，以热带地区海南儋州不同林龄（4、15、31a）橡胶人工林为研究对象，采用Hedley连续浸提法研究了土壤磷组分，磷脂脂肪酸法（Phospholipid fatty acids，PLFAs）分析了土壤微生物群落。结果表明，在橡胶林内各磷组分的相对含量大小顺序为：闭蓄态磷 > 中等活性态磷 > 活性态磷 > 团聚体内磷 > 钙磷。随着林龄的增加，橡胶林土壤中的磷组分发生显著变化。4、15、31a橡胶林的闭蓄态磷分别占总提取磷的52.61%、47.17%和34.91%，而活性态磷分别占总提取磷的6.67%、11.32%、13.68%。土壤总微生物、细菌、革兰氏阴性菌（G-）、革兰氏阳性菌（G+）的PLFAs含量均表现为15a > 4a > 31a，而31a橡胶林放线菌、真菌（F）和丛枝菌根真菌（AMF）的PLFAs含量均低于4a和15a。冗余分析（RDA）显示，全氮、有机碳、pH、F、AMF、G-、G+是引起不同林龄橡胶林土壤磷组分变化的重要贡献因子。研究表明，在橡胶林发育过程中，土壤理化性质和微生物群落发生了明显的变化，进而影响到土壤磷的转化过程。 Abstract:Phosphorus (P) is recognized as one of the most limiting nutrients for primary production in tropical forests because much of the soil P stocks are geochemically bound to iron and aluminum oxides in forms that are largely unavailable for plant uptake. The availability of P to microorganisms and plants can be assessed by evaluating different soil P fractions, and soil P occurs in both organic and inorganic forms, which differ in behavior, mobility, and bioavailability (i.e., labile P, moderately labile P, non-labile P). Labile and non-labile P fractions can serve as sources or sinks of available P, and non-labile P can be released into soil solutions as available P through desorption when the content of available P decreases in the soil. Therefore, it is critical to understand the transformation between different soil P fractions when developing best practices for fertilizer management that aim to enhance the P use efficiency of agricultural systems. Soil microorganisms are important mediators of P mineralization and immobilization, owing to their ability to reduce P availability by immobilizing P in their biomass, which subsequently increases stocks of microbial P in the soil. In addition, lower available P content was observed in tropical soil, accompanied by higher soil phosphatase activity. Furthermore, arbuscular mycorrhizal fungi (AMF) can take up P from pools that are normally considered unavailable to plants. However, the relationship between the dynamics of soil P forms, soil properties, and soil microbial communities has yet to be established in rubber plantation at different ages. Therefore, we compared the soil P fractions (i.e., labile P, moderately labile P, sonicate P, Ca-P, and occluded P) and soil microbial community composition of 4-, 15-, and 31-year-old rubber plantations on Hainan Island, Southern China. The aims of this study were (1) to determine whether the soil P stock and fractions would change with increasing plantation age; (2) to test whether the composition of soil microbial communities would change with plantation age; and (3) to quantify the relationships between P fraction, microbial community, and other soil attributes. The results could be used to develop recommended P fertilizer management practices for sustainable rubber plantations. We found that occluded P was the largest phosphorus fraction, followed by moderately labile P, labile P, sonicate P, and Ca-P in all plantations. The levels of bacteria and both gram-positive and gram-negative bacterial Phospholipid fatty acids (PLFAs) were highest in the 15-year-old plantation, whereas the levels of actinomycetes, arbuscular mycorrhizal fungi (16:1ω5c), and fungal PLFAs were lowest in the 31-year-old plantation. The level of soil acid phosphatase activity did not change with increasing plantation age, and redundancy analysis indicated that both biotic and abiotic factors were important contributors to variation in soil P fractions. Accordingly, the present study demonstrates that the age of rubber plantations significantly affects the soil physicochemical properties and microbial communities of rubber plantations and, consequently, soil P availability and cycling. 参考文献 相似文献 引证文献