Moreover, the concomitant increases of vapor pressure deficit and temperature could exacerbate the drying effects on soybean growth and yield and lead to reductions in photosynthetic rate and yield formation (fertile pods, seed number, and seed size) [25]. In the present study, warming increased leaf VPD at the anthesis, pod setting, and filling stages and led to decreases in leaf photosynthetic rates and yield (Table 1; Fig. 3c, d). In addition, the decreases in 100-seed weight and harvest index of soybean may have contributed to yield reduction.