贡嘎山酸性土壤微生物量磷紧密关联碳酸氢钠提取态有机磷

Microbial Biomass Phosphorus is Closely Linked to Sodium Bicarbonate Extractable Organic P in Acid Soil of Mt.Gongga

有效磷是土壤中最重要的磷组分,被广泛用于评估各种生态系统的土壤磷营养。然而,很少有研究基于野外数据评估有效磷的来源。本研究通过野外调查和室内试验,展示和评估了微生物量磷(MBP)和微生物群落对贡嘎山酸性土中有效磷组分的关联性。结果发现,微生物功能组脂肪酸显著解释有效磷变异性,尤其细菌脂肪酸强烈关联有效磷。与Hedley磷连续提取法中其他有效磷相比,仅碳酸氢钠提取态有机磷(NaHCO_3-Po)强烈关联MBP。本研究的数据分析、实验结果和以往的研究结果证明MBP与NaHCO_3-Po之间的这种关联性是直接的:微生物死亡裂解释放有效磷是导致这种联系的主要原因。这些结果揭示了微生物量磷测定方法与Hedley磷连续提取法测定方法的关联性:酸性土中MBP是Hedley磷连续提取法中NaHCO_3-Po的主要来源,也强调了Hedley磷连续提取法在评估微生物对土壤磷有效性作用中的重要参考性。

The available phosphorus（P） is the most important component of soil P,which is widely used for assessing the nutrition of soil P in various ecosystems.However,few studies had been done for evaluation of its source in terms of field observation.Through field investigation and laboratory test,this study presented and evaluated the relation between available P fractions and soil microbial biomass P（MBP） in acidic soils of Mt.Gongga.It showed that microbial functional group lipids could be used to explain the variations of available P profiles across all plots.More importantly,it exhibited a close connection between bacterial lipids and available P.Compared with other available P fractions determined by modified Hedley sequential method,only the sodium bicarbonate extractable organic P（NaHCO3-Po） strongly related to MBP.Previous researches and our analysis can prove that the relation between MBP and NaHCO3-Po was direct：microbial cells cracking was the main reason for the relation.The results also revealed the relation between two methods（i.e.,MBP determination method and Hedley sequential-P-fractionation method） ：the MBP was a major component of NaHCO3-Po through Hedley sequential-P-fractionation method in the acid soil.It also highlighted reference values of Hedley sequential-Pfractionation method in assessing the role of soil microorganism in bioavailability of P.