However, soil temperature between 11:00 and 18:00 was lower after mulching than before mulching, suggesting that mulching can decrease the fluctuation of soil temperature between day and night. The greater the mulch thickness, the lower the peak value of the soil temperature at 5 cm depth in day time, and the smaller the soil temperature difference between day and night. Soil temperature with 7 cm thick mulch was similar to that with 9 cm thick mulch, indicating that the effect of mulch thickness on soil temperature was minimal beyond 7 cm mulch thickness.Soil temperature was closely related to mulch thickness with a quadratic function between these two factors (Fig. 3). Consequently,the soil temperature at 8:00 was higher with mulch than without mulch. When mulch thickness was