Abelardo Nunez-Barrios1, Jose Luis Ibave-Gonzalez1, Gerrit Hoogenboom2, and Scott NeSmith2. (1) Universidad de Chihuahua, Campus Universitario 1, Chihuahua, Mexico, (2) University of Georgia, 1109 Experiment Street, Department of Biology and Agriculture Engineering, Griffin, GA 30223-1797
Maize and dry beans are some of the most important crops growing in the semiarid highlands of Mexico. Due to the higher than historical temperatures observed in the last five years, global warming may be influencing the availability of food and income for farmers. However it is still not well understood how climate change may influence the yield of maize and beans in this region of the world. The objectives of this study were: 1. To understand the effect of increasing temperature and CO2 concentration on maize and dry beans growth. 2. To map regions with different production risks for maize and dry beans in Mexico’s highlands. The first part of this research was conducted in the Georgia’s Envirotron at the University of Georgia using three temperatures (25,30,35°C) and two levels of CO2 (400 and 800 ppm). In the second part of this study, a GIS tool was applied to classify the maize and dry beans producing areas based in a temperature gradient that cover the highlands of Mexico. Results showed that increasing temperatures had a positive effect on maize growth and development. Plant dry matter was increased by 12% between 25 and 30°C. Flowering was 9 days earlier in the 30°C treatment as compared to the 25°C treatment under both concentration of CO2. For beans, dry matter production and flowering time were affected for both, temperature and CO2 levels. Increasing CO2 concentration from 400 to 800 ppm caused an augmentation of shoot dry matter but temperature above 25°were detrimental for bean growth. Summer temperatures in the rain fed area of Mexico’s highlands have a gradient that goes from 18.5 to 23.8°C and with an increase of temperature between 1 and 3°C we found that about 19.4% of the dry bean producing area (about 200 000ha) may be affected by global warming.