Effects of Phosphorus Addition on Biomass and Ecological Stoichiometric Characteristics of Organs in Poa pratensis var.anceps Gaud cv.Qinghai
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.
万方数据
维普
