Response of Soybean Yield to Daytime Temperature Change during Seed Filling: A Long-Term Field Study in Northeast China

Abstract

Daytime temperature during seed filling is a crucial determinant of grain yield in pulse crops. Although there is much research about the effect of daytime temperature during seed filling on soybean yield in temperature-controlled chambers, the effect in the field has been little explored. Long-term manipulative field experiments are important tools to provide accurate information for revealing the impacts of climate change on crop yields. Using the field records of a long-term fertilization experiment conducted in Northeast China, we analyzed the response of soybean yields to mean daily maximum temperature during seed filling over the period 1987−2007. The results showed that there was a clear positive response of soybean yields to increased mean daily maximum temperature during seed filling ranged from 20 to 24ºC. When compared with the average soybean yields over the last two decades, grain yields increased by 6−10% for each 1ºC increase in mean daily maximum temperature during seed filling and more than 22% of yield trends can be explained. These findings provide a direct evidence for the response of soybean yield to climate change in the field study.