The effect of global warming on dry bean and maize production on the highlands of Mexico

Abstract

Global warming may affect growth and production of maize and beans. A study was conducted in the Georgia Environtron Laboratory of the University of Georgia. A factorial experiment with four temperatures (20, 25, 30 and 35°C) and two CO2 levels (400 and 800 ppm) was established in chambers with control environment. Data were taken on dry matter production, plant height, stages of development and yield per plant. For maize, temperatures had a significant effect on plant height, flowering and dry matter accumulation but plant response to CO2 concentrations was not significant. Dry beans responded to both, temperatures and CO2 treatments. For 20 and 30°C, the increment of dry matter was 72 and 76% increasing CO2 from 400 to 800ppm. Beyond 30°C, accumulation of dry matter in beans was drastically diminished. No reduction on maize yield was observed in the range of temperatures treatments, but for dry bean, seed production showed a significant decreased with temperatures above 25°C. A GIS system was used to estimate the risk of maize and bean production areas under a global warming scenario (+3°C). It was found that more than 100 000 ha planted with beans are under higher risk. Maize production seems not to be affected neither for increasing temperatures nor greater concentration of CO2.