土壤学报2025，Vol.62Issue(3)：893-904,12.DOI:10.11766/trxb202401090018
短期和长期氮磷添加对青藏高原草甸土壤微生物残体积累系数的影响
Effects of Short-term and Long-term Nitrogen and Phosphorus Additions on Microbial Necromass Accumulation Coefficients in Meadow Soils of the Qinghai-Tibet Plateau
摘要
Abstract
[Objective]Microbes and their necromass play a key role in the accumulation and long-term sequestration of soil organic carbon(SOC).Moreover,continuous increases in nitrogen(N)and phosphorus(P)inputs can significantly affect microbe-mediated SOC accumulation processes.The microbial necromass accumulation coefficient(NAC),which quantifies the accumulation of microbial necromass per unit of microbial biomass,plays a key role in assessing the efficiency of microbial necromass accumulation.However,the influence of short-term and long-term additions of N and P on this coefficient within meadow ecosystems remains unclear.This study focused on investigating the differential responses of NAC to(1)short-term and long-term N and P additions and(2)additions of N and P across different soil layers.[Method]To explore the response of NAC to N and P additions,this study analyzed soil samples from the meadow on the Qinghai-Tibet Plateau subjected to 1 year(short-term)and 10 years(long-term)of N and P additions.It was measured the soil microbial necromass carbon(MNC)and the soil microbial biomass carbon(MBC),and calculated the value of NAC.Additionally,considering other environmental factors including soil physical and chemical properties,microbial extracellular enzyme activities,and plant biomass,the main influencing factors of NAC were identified.[Result]The results showed that after short-term N and P additions,the NAC values in the 0-10 cm and 20-30 cm soil layers were 31.33±2.97(mean±SE)and 38.12±3.90,respectively,and N and P additions had no significant effect on NAC(P>0.05).After long-term additions of N and P,the NAC values in the 0-10 cm and 20-30 cm soil layers were 14.46±1.12 and 17.49±3.22,respectively;and the additions of N and P significantly reduced the NAC in the 20-30 cm layer(P<0.05).The results of the Random Forest indicated that pH was the most important factor affecting NAC,and the correlation analysis revealed a significant positive relationship between soil pH and NAC.Moreover,the long-term N addition,P addition and simultaneous addition of N and P significantly reduced the pH of the 20-30 cm soil layer.These findings suggest that the decrease in soil pH due to long-term N and P supplementation is the main cause of the reduction in NAC.The lowered soil pH may lead to the dissolution of minerals,thereby reducing the mineral protection of MNC,making it more susceptible to decomposition,ultimately decreasing the NAC of microorganisms.[Conclusion]In summary,changes in pH resulting from long-term nutrient additions dominated the changes in NAC.In the context of ongoing increases in N and P deposition,it is advisable to closely monitor changes in soil pH and implement timely measures to maintain the stability of SOC.This study explores the differential responses of NAC to N and P additions and their influencing factors,providing data support for understanding microbial-mediated carbon accumulation under the context of increasing N and P deposition.关键词
土壤有机碳/微生物残体积累系数/氮磷添加/pH/青藏高原Key words
Soil organic carbon/Microbial necromass accumulation coefficient/Nitrogen and phosphorus addition/pH/Qinghai-Tibet Plateau分类
农业科技引用本文复制引用
李一凡,石碧婉,杨志颖,高文静,马田,朱剑霄,贺金生..短期和长期氮磷添加对青藏高原草甸土壤微生物残体积累系数的影响[J].土壤学报,2025,62(3):893-904,12.基金项目
国家自然科学基金项目(42301105)、兰州大学"双一流"引导专项:队伍建设经费(561119221)资助 Supported by the National Natural Science Foundation of China(No.42301105),and the"Double First Class Initiative"Guided Project Team Building-Funding-Research Startup Fee of Lanzhou University,China(No.561119221) （42301105）
