添加氮磷与菌根抑菌剂对荒漠草原草地净初级生产力的影响

Effects of Nitrogen,Phosphorus and Fungicide Additions on Net Primary Productivity in Desert Steppe

采用原位控制试验的方法,以宁夏东部温性荒漠草原植物群落为研究对象,解析氮、磷添加与菌根抑菌剂对草原植物净初级生产力(NPP)的影响。结果表明:氮、磷添加与菌根抑菌剂显著提高地上净初级生产力(ANPP)、地下净初级生产力(BNPP)与NPP(P<0.01)。磷与菌根抑菌剂添加的拮抗效应显著改变ANPP与NPP;施磷处理下菌根抑菌剂添加极显著增加ANPP与NPP(P<0.01);不施磷处理下菌根抑菌剂添加对ANPP与NPP无显著影响。氮、磷添加对ANPP、BNPP与NPP无显著交互作用。氮添加显著增加10~30 cm土层BNPP(P<0.01)。磷添加显著促进0~10 cm、10~30 cm与30~40 cm土层BNPP(P<0.01)。施磷处理下菌根抑菌剂添加显著增加深根型植物地上生物量(P<0.01)。深根型植物地上生物量占比与BNPP呈极显著正相关关系(P<0.01)。磷添加通过提高深根型植物地上生物量占比,进而促进BNPP增加。本研究结果表明,宁夏东部温性荒漠草原初级生产力受到氮、磷添加与菌根抑菌剂的影响;与氮、菌根抑菌剂添加相比,磷添加对NPP的作用强度更高。

An in-situ experiment was conducted to evaluate the effects of nitrogen(N),phosphorus(P),and fungicide application on net primary productivity(NPP)in desert steppe in eastern Ningxia,China.The results showed that N,P and fungicide addition significantly increased aboveground net primary productivity(ANPP),belowground net primary productivity(BNPP),and NPP(P<0.01).P and fungicide additions displayed antagonistic effects on ANPP and NPP.Fungicide had minimal effects on control plots but significantly increased ANPP and NPP in P addition plots(P<0.01).No significant interactive effects of N and P on any NPP measures were observed.N addition significantly increased BNPP in the 10-30 cm soil layer(P<0.01),while P addition significantly promoted BNPP across all three soil depths(0-10 cm,10-30 cm and 30-40 cm).In P addition plots,fungicide significantly increased shoot biomass of deep-rooted plants(P<0.01).The relative biomass of deep-rooted plants positively correlated with BNPP(P<0.01).This findings suggested that P addition promoted BNPP by enhancing the relative biomass of deep-rooted plants.Overall,this study demonstrated that N,P,and fungicide additions all influenced NPP in eastern Ningxia desert steppe,with P addition having the strongest effect.