Impacts of Atmospheric Temperature - Humidity Changes on Yield Quality of Thai Soybean Cultivar

Abstract

This study aimed to assess the impact of atmospheric temperature and humidity change on yield of Thai soybean, Chiang Mai 60 cultivar. The research experiment was conducted during July - October 2013 at Naresuan University Crops Field, Phitsanulok, Thailand. Soybean seed Chiang Mai 60 cultivars were planted in 16 open top chambers (OTCs) under 4 different temperature and humidity levels. The four simulated climate change situations in OTCs were, lower than ambient temperature, higher than ambient temperature, combined elevated temperature and high humidity and ambient temperature level, which all were controlled by an electrical system. Results indicated that yield loss by statistical significance occurred in all Low-level temperature treatment (25±2.9 °C), High-level temperature treatment (37±2.2°C), and high Temperature-humidity (36±2.8°C/ 81.7±2.2%), compared with ambient-level temperature treatment (31±1.7°C). Exposure to simulated climate change situation in Low-level temperature treatment obviously reduced total pod/plant and total seed/plant by 40.8% and 48.5%, respectively. High-level temperature caused yield loss in total pods/plant and total seeds/plant by 35.6% and 39.5%, respectively. The combined effect of high temperature and humidity on soybean crop reduced total pods/plant and total seeds/plant about 36.4% and 47%, respectively. Finally, low temperature evidently increased in lipid content and all types of fatty acid in experiment, whereas the high temperature treatment could reduce the total mono-unsaturated fatty acids. It was concluded that temperature change situations at above and lower than ambient level in growing season could induce yield loss and some fatty acid in Thai soybean, Chiang Mai 60.