Abstract
ABSTRACTTo estimate the effect of elevated [CO2] on nitrogen (N) and phosphorus (P) dynamics and productivity in summer maize, a field experiment was conducted in open-top chambers (OTCs) at different [CO2] (550 μmol/mol, T1; 750 μmol/mol, T2 and a control, CK) in Nanjing in Jiangsu Province, China. The results showed that maize total N and P accumulation were 13.23–66.56% higher in the elevated [CO2] treatments than in the CK plots during the jointing, anthesis and maturity stages. There was only a significant difference in total N accumulation between the T2 treatment and CK at maturity (P < 0.05). However, rising [CO2] decreased the N and P concentrations in each biomass fraction. Elevated [CO2] increased the amounts of N and P translocation, resulting in the contribution of translocated N to grain N. Similarly, rising [CO2] increased N and P translocation efficiencies, N or P harvest index, and N or P utilization efficiency based on grain yield and N or P utilization efficiencies based on biomass in both growing seasons. In addition, elevated [CO2] significantly increased aboveground biomass at three stages, including 4.73–12.34% at maturity. The grain yields of summer maize increased by 21.28% and 29.07% in the two elevated [CO2] plots. Furthermore, spike numbers, kernels per spike and 100-grain weight were increased by elevated [CO2] treatments. Kernels per spike and grain yield showed obvious differences between elevated [CO2] treatments and CK (p < 0.05).
Published Version
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