施肥对宁夏主要类型土壤-微生物-胞外酶化学计量特征的影响

Effects of fertilization on C∶N∶P stoichiometry of soil,microbes andectoenzymes in major soil types in Ningxia

【目的】研究施肥对宁夏主要类型土壤碳氮磷、微生物生物量碳氮磷、胞外酶活性及其化学计量特征的影响,为农田养分调控和土壤可持续利用提供科学依据。【方法】以宁夏主要类型土壤(灌淤土、黄绵土、灰钙土)为研究对象,分析施肥(不施肥(对照)、单施化肥、化肥配施有机肥)对土壤有机碳(C)、全氮(N)、全磷(P),微生物生物量C、N、P(MBC、MBN、MBP)含量和胞外酶(β-葡糖苷酶(BG)、α-纤维素酶(CBH)、β-乙酰葡糖胺糖苷酶(NAG)、亮氨酸氨基肽酶(LAP)、碱性磷酸酶(AKP))活性的影响,并且分析了土壤碳氮磷含量与微生物生物量碳氮磷、胞外酶活性及其化学计量特征的相关性。【结果】(1)施肥和土壤类型均对土壤C、N、P含量影响极显著,而二者的交互作用仅对土壤C影响显著。土壤类型对C/P、N/P影响极显著,施肥对C/N、C/P影响显著。与对照相比,化肥配施有机肥处理显著增加了黄绵土C含量以及各类型土壤N、P含量和N/P。(2)施肥对土壤MBC、MBN、MBP含量及其化学计量比影响显著或极显著,而土壤类型仅对MBP含量及MBC/MBP影响极显著,二者交互作用对MBP含量和MBC/MBP、MBN/MBP影响极显著。3个土壤类型中,化肥配施有机肥处理对黄绵土MBC、MBN、MBP含量的增加作用最为明显,而对黄绵土MBC/MBN、MBC/MBP、MBN/MBP的降低作用最为明显。(3)施肥和土壤类型对土壤胞外酶化学计量特征有极显著影响,二者的交互作用对CBH、NAG、LAP、AKP活性有极显著影响。与对照相比,化肥配施有机肥显著降低了灰钙土LAP、NAG、AKP活性。(4)相关性分析表明,土壤有机碳与(NAG+LAP)/AKP呈显著正相关,而与(BG+CBH)/(NAG+LAP)、(BG+CBH)/AKP呈显著负相关。土壤全P与(BG+CBH)/(NAG+LAP)、(BG+CBH)/AKP呈极显著正相关,而与(NAG+LAP)/AKP呈极显著负相关。土壤C/N与MBC/MBP、MBN/MBP呈显著或极显著正相关,而与MBP呈显著负相关。【结论】化肥配施有机肥有利于增加宁夏主要类型土壤全量养分和微生物生物量,维持土壤养分平衡,但在实际应用中应考虑土壤类型的差异。

【Objective】The effects of fertilization on soil-microbe-ectoenzyme C∶N∶P stoichiometry in main soil types in Ningxia were analyzed to provide basis for farmland nutrient regulation and sustainable soil utilization.【Method】In this study,major soil types of anthropogenic-alluvial soil,loess soil and grey desert soil in Ningxia were selected to analyze the effects of fertilization(no fertilizer application as control,single chemical fertilizer application and chemical fertilizer combined with organic fertilizer application)on soil C,N and P concentrations,microbial biomass C,N and P(MBC,MBN and MBP)concentrations,as well as enzyme activities(β-glucosidase(BG),α-D-cellobiohydrolase(CBH),β-acetylgucosaminidase(NAG),L-leucine aminopeptidase(LAP)and acid phosphatase(AKP))in soil.The covariations of soil-microbe-ectoenzyme C∶N∶P stoichiometry were also explored.【Result】(1)Fertilization and soil types had extremely significant effects on soil C,N and P contents,while their interaction only had significant effects on soil C.Soil type had an extremely significant effect on C/P and N/P,and fertilization had a significant effect on C/N and C/P.Compared with the control group,the combined application of chemical fertilizer and organic fertilizer significantly increased C content in loess soil as well as N and P contents and N/P in all types.(2)Fertilization had significant or extremely significant effects on contents and stoichiometric ratios of soil MBC,MBN and MBP,while soil type only had extremely significant effects on soil MBP content and MBC/MBP.Their interaction had extremely significant effects on soil MBP content and MBC/MBP and MBN/MBP.Among three soil types,the combined application of chemical fertilizer and organic fertilizer had the most significant effects on the increases of MBC,MBN and MBP contents and the decreases of MBC/MBN,MBC/MBP and MBN/MBP in loess soil.(3)Fertilization and soil type had extremely significant effects on stoichiometry of soil extracellular enzymes,and their interaction had an extremely significant impact on CBH,NAG,LAP and AKP activities.Compared with the control group,the combined application of chemical fertilizer and organic fertilizer significantly reduced the activities of LAP,NAG and AKP in grey desert soil.(4)Correlation analysis showed that soil organic carbon was significantly positively correlated with(NAG+LAP)/AKP,and negatively correlated with(BG+CBH)/(NAG+LAP)and(BG+CBH)/AKP.Total P was extremely significantly positively correlated with(BG+CBH)/(NAG+LAP)and(BG+CBH)/AKP,while negatively correlated with(NAG+LAP)/AKP.Soil C/N was significantly or extremely significantly positively correlated with MBC/MBP and MBN/MBP,while significantly negatively correlated with MBP.【Conclusion】The combination of chemical fertilizer and organic fertilizer was beneficial for increasing soil nutrients and microbial biomass and maintaining soil nutrient balance in Ningxia.Soil type should also be considered in practical application.