Effects of elevated CO2 on growth parameters of soybean (Glycine max [L.] Merr.) grown in fly-ash amended soils

RODRIGUEZ, J.H.; HÖGY P.; FRANZARING J.; FANGMEIER A.; PIGNATA, M.L.; KLUMPP A.

Marburg, Alemania

Conferencia; Vehandlungen der Gesellschaft für Ökologie. Symposium 14: Response to Environmental Changes. 37th Annual conference of the Ecological Society of Germany, Austria and Switzerland; 2007

Ecological Society of Germany, Austria and Switzerland

Soybean (Glycine max [L.] Merr.) is the main crop per cultivated area, production volume and gross value in the Province of Córdoba (Argentina) like in many regions worldwide. Increases of atmospheric CO2 concentrations due to anthropogenic emissions (IPCC 2007) may significantly influence agricultural yield because CO2 as a primary substrate for photosynthesis will stimulate growth of C3 crop species. On the other hand, large areas in Córdoba present elevated levels of toxic elements, such as heavy metals, in air, water and soil due to industrial activities. This situation implies a serious risk for the health of the local population and the consumers of food produced in this region. In order to investigate the interactions of CO2 and heavy metals, soybean was grown in standard soil amended with different proportions of fly ash (0%, 1%, 10%, 15%, 25%) from a coal-fired power plant. The soybeans were exposed in climatic chambers to two concentrations of CO2 (400 and 600 ppm) from emergence to grain maturity simulating the climatic conditions of Córdoba. Ten morphological parameters, aboveground and root biomass, pigment and carbohydrate concentrations were determined at three growth stages (vegetative, reproductive/grain filling, maturity). First results revealed that elevated CO2 caused a stimulation of all growth parameters. When evaluating the combination of CO2 and different fly-ash concentrations, the plants grown in soils with higher proportion of fly-ash showed a reduction in yield. The data demonstrate that in areas burdened with heavy metals soybean yield can be adversely affected despite the CO2 fertilization effect.