为探讨N添加对墨西哥柏人工林土壤、叶片碳氮磷含量及其生态化学计量特征变化的影响,共设置F0,F1(24kg hm-2a-1),F2(48 kg hm-2a-1),F3(72 kg hm-2a-1),F4(96 kg hm-2a-1),F5(120 kg hm-2a-1) 6个不同施N量处理。结果表明:(1)随施N量的...为探讨N添加对墨西哥柏人工林土壤、叶片碳氮磷含量及其生态化学计量特征变化的影响,共设置F0,F1(24kg hm-2a-1),F2(48 kg hm-2a-1),F3(72 kg hm-2a-1),F4(96 kg hm-2a-1),F5(120 kg hm-2a-1) 6个不同施N量处理。结果表明:(1)随施N量的增加土壤有机碳,全氮,全磷含量呈先升高后降低的趋势,并在F3样地取得最大值,分别是2. 50%,0. 22%,0. 13%。土壤C/N值随施肥量的增加而显著增加。但土壤N/P,C/P值随施肥量的增加呈降低-升高的趋势,在F2样地出现最低值,分别是0. 92,11. 01。(2)叶片CNP含量未受到N添加的显著影响,叶片C、N含量在F3样地取得最大值,分别为47. 89%,1. 50%,叶片P含量在F2样地取得最大值,为0. 24%。同样N添加对叶片C/N,C/P值并没有产生显著影响,(3)根据聚类分析可以发现,N添加对土壤、叶片碳氮磷含量及化学计量比的影响可以分为3组,其中F2可作为盱眙墨西哥柏人工林氮添加的参考。根据因子分析可以发现,土壤、叶片CNP化学计量比对N添加的响应比较灵敏。展开更多
Aims As the determinant of water availability in drylands,groundwater plays a fundamental role in regulating vegetation distribution and ecosystem processes.Although considerable progress has been made over the past y...Aims As the determinant of water availability in drylands,groundwater plays a fundamental role in regulating vegetation distribution and ecosystem processes.Although considerable progress has been made over the past years in the relationship between environment stress and plant community-level traits,the potential influence of water stress induced by groundwater changes on plant community-level stoichiometry remains largely unclear.Here,we examined whether belowground and aboveground community-level stoichiometry responded differently to groundwater changes.Methods We measured nitrogen(N)and phosphorus(P)concentrations in plant leaves and fine-roots of 110 plots under a broad range of groundwater depths in a typical arid inland river basin.We examined the spatial patterns and drivers of community-level N:P stoichiometry in leaves and fine-roots.Important Findings Community-level leaf and fine-root N,P and N:P ratios were mainly determined by groundwater,vegetation types and species composition,among which groundwater played a dominant role.Groundwater indirectly regulated community-level N:P stoichiometry through affecting vegetation types and species composition.Vegetation types and species composition had significant direct influences on communitylevel N:P stoichiometry.Furthermore,groundwater depth had opposite influences on community-level leaf and fine-root N:P stoichiometry.Groundwater depth regulated vegetation types and further decreased leaf N,P but increased leaf N:P ratios and fine-root N.Groundwater depth had a positive indirect impact on fine-root P but a negative indirect impact on fine-root N:P ratios primarily by affecting species composition.Our findings indicate that groundwater rather than climate conditions effectively regulates community-level N:P stoichiometry,and below-and aboveground N:P stoichiometry has opposite responses to groundwater.展开更多
文摘为探讨N添加对墨西哥柏人工林土壤、叶片碳氮磷含量及其生态化学计量特征变化的影响,共设置F0,F1(24kg hm-2a-1),F2(48 kg hm-2a-1),F3(72 kg hm-2a-1),F4(96 kg hm-2a-1),F5(120 kg hm-2a-1) 6个不同施N量处理。结果表明:(1)随施N量的增加土壤有机碳,全氮,全磷含量呈先升高后降低的趋势,并在F3样地取得最大值,分别是2. 50%,0. 22%,0. 13%。土壤C/N值随施肥量的增加而显著增加。但土壤N/P,C/P值随施肥量的增加呈降低-升高的趋势,在F2样地出现最低值,分别是0. 92,11. 01。(2)叶片CNP含量未受到N添加的显著影响,叶片C、N含量在F3样地取得最大值,分别为47. 89%,1. 50%,叶片P含量在F2样地取得最大值,为0. 24%。同样N添加对叶片C/N,C/P值并没有产生显著影响,(3)根据聚类分析可以发现,N添加对土壤、叶片碳氮磷含量及化学计量比的影响可以分为3组,其中F2可作为盱眙墨西哥柏人工林氮添加的参考。根据因子分析可以发现,土壤、叶片CNP化学计量比对N添加的响应比较灵敏。
基金This work was supported by grants from National Natural Science Foundation of China(item identification numbers:31971538 and 31570610).
文摘Aims As the determinant of water availability in drylands,groundwater plays a fundamental role in regulating vegetation distribution and ecosystem processes.Although considerable progress has been made over the past years in the relationship between environment stress and plant community-level traits,the potential influence of water stress induced by groundwater changes on plant community-level stoichiometry remains largely unclear.Here,we examined whether belowground and aboveground community-level stoichiometry responded differently to groundwater changes.Methods We measured nitrogen(N)and phosphorus(P)concentrations in plant leaves and fine-roots of 110 plots under a broad range of groundwater depths in a typical arid inland river basin.We examined the spatial patterns and drivers of community-level N:P stoichiometry in leaves and fine-roots.Important Findings Community-level leaf and fine-root N,P and N:P ratios were mainly determined by groundwater,vegetation types and species composition,among which groundwater played a dominant role.Groundwater indirectly regulated community-level N:P stoichiometry through affecting vegetation types and species composition.Vegetation types and species composition had significant direct influences on communitylevel N:P stoichiometry.Furthermore,groundwater depth had opposite influences on community-level leaf and fine-root N:P stoichiometry.Groundwater depth regulated vegetation types and further decreased leaf N,P but increased leaf N:P ratios and fine-root N.Groundwater depth had a positive indirect impact on fine-root P but a negative indirect impact on fine-root N:P ratios primarily by affecting species composition.Our findings indicate that groundwater rather than climate conditions effectively regulates community-level N:P stoichiometry,and below-and aboveground N:P stoichiometry has opposite responses to groundwater.
