Supplementing forage crops with an appropriate amount of phosphorus(P)effectively enhances nitrogen metabolism and utilization,leading to improved forage yield and stress resilience.This study investi-gated the effects of P addition on the biomass distribution,tissue ecological stoichiometric characteristics,and their interactions in different organs(roots,stems,and leaves)of a 5-year-old Poa pratensis var.anceps Gaud cv.Qinghai.Seven P addition gradients were applied:0,30,60,90,120,150,180 kg/hm2.The results showed as follows:(1)Plant biomass initially increased withing increasing P addition,peaking at 90 kg/hm2 with a 73.99%rise in aboveground biomass and a 7.31%rise in belowground biomass compared to the con-trol.This trend gradually reversed at higher P levels;(2)Similarly,carbon(C),nitrogen(N),and P con-tents in different organs peaked at specific P addition levels before declining.Notably,root N and P reached their highest values(37.05%and 34.63%increases,respectively)at 150 kg/hm2,while leaf N and P peaked at 90 kg/hm2(11.60%and 37.66%higher than the control,respectively).(3)Interest-ingly,leaf C and N content consistently exceeded those in roots,while root P content was higher than in leaves;(4)Importantly,all organ biomasses displayed significant positive correlations with C,N and P con-tents(P<0.05).Notably,aboveground biomass(leaves and stems)exhibited a highly significant negative correlation with C∶N and C∶P(P<0.01).These observations suggest that P addition significantly regu-lates nutrient uptake and balance in Poa pratensis var.anceps Gaud cv.Qinghai.Furthermore,our find-ings indicate that moderate P addition(90 kg/hm2)offers a crucial balance between maximizing biomass production and achieving efficient utilization in mature stands of this forage grass.
维普
万方数据
