Does phosphorus stimulate the effect of elevated [CO2] on growth and symbiotic nitrogen fixation of grain and pasture legumes?

作者：Lam Shu Kee; Chen Deli^*; Norton Rob; Armstrong Roger

来源：Crop and Pasture Science, 2012, 63(1): 53-62.

DOI：10.1071/CP11296

• barrel medic
• chickpea
• elevated carbon dioxide
• field pea
• nitrogen fixation
• soil phosphorus status

The effect of elevated [CO2] (700 mmol/mol) and phosphorus (P) supply on the growth and symbiotic N-2 fixation of chickpea (Cicer arietinum L.), field pea (Pisum sativum L.) and barrel medic (Medicago truncatula Gaertn.) were investigated in the glasshouse. The effect of elevated [CO2] on the growth and N-2 fixation at various growth stages of the chickpea and field pea plants (grown on a Vertosol) were also examined. Elevated [CO2] generally increased the aboveground biomass of chickpea (by 18-64%), field pea (by 24-57%) and barrel medic (by 49-82%), but the effect was greater when P was non-limiting. Elevated [CO2] only stimulated grain yield of chickpea (by 70%) and field pea (by 21%) if P supply was adequate. Elevated [CO2] reduced the grain protein concentration of chickpea (by 17-18%) regardless of P input, but increased that of field pea (by 11%) when soil P was limiting but had no effect at adequate P. The percentage of shoot N derived from the atmosphere (% Ndfa) of the three legumes was unaffected by elevated [CO2] regardless of soil P supply. Elevated [CO2] increased the amount of N fixed by chickpea (by 20-86%), field pea (by 44-51%) and barrel medic (by 114-250%) under P fertilisation, but had no significant effect when soil P was deficient. These results suggest that the predictions of future climates on the potential contribution of legumes to maintaining soil N fertility will depend on the particular response of a species to soil P status.

• 出版日期2012