Straw usually refers to the aboveground part of crops after grain harvesting and is the main byproduct of crop production. Straw return is considered an effective way of recycling crop straw residues. In this study, a 5.5-year field experiment was conducted to evaluate different total straw returning methods using the following treatments:ditch-buried return at 20 cm and at 40 cm soil depths and the control treatment of conventional tillage with no straw return. The amount of rice and wheat straw returned was 2 kg/m² and 1 kg/m², respectively. This study investigated the soil water potential and soil temperature at the different ditch-buried return depths, as well as the effect of long-term ditch-buried returns to a depth of 20 cm on the bulk density and total porosity of soils. Our results suggested that a ditch-buried return to a depth of 20 cm could reduce soil bulk density and increase total porosity compared with the control treatment. The beneficial effects on soil structure were present even after 4.5 years. The effect gradually declined as the length of time after straw return increased. In the 0-7 cm soil layer, the bulk density and total porosity of ditch-buried return at 20 cm and 40 cm depth gradually became closer to the control treatment. However, there were significant differences between both ditch-buried straw return depths and the control treatment in the 7-14 cm soil layer. When rainfall was high (26.6 mm), the variation in soil water potentials of the ditch-buried return to depths of 20 cm and 40 cm were 15.7 kPa and 14.8 kPa, respectively, within two hours, whereas the change in the soil water potential of control treatment was 2.2 kPa. This indicates that the soil water potentials of ditch-buried return to depths of 20 cm and 40 cm show a faster increase than the control treatment. When rainfall was low (10 mm), the water potential of ditch-buried return to a depth of 40 cm showed a faster increase than that of ditch-buried return to a depth of 20 cm, which was faster than the control treatment. It was found that the water potentials of ditch-buried return to depths of 20 cm and 40 cm decreased rapidly and were lower than the control treatment 12 days after rainfall. The changes in soil water potentials for both ditch-buried straw returns and the control treatment were 187.62 kPa, 141.38 kPa, and 104.48 kPa, respectively. The soil water potential of each treatment over 40 consecutive days was control treatment > ditch-buried return 40 cm > ditch-buried return 20 cm. On average, the soil water potentials of ditch-buried return to depths of 20 cm and 40 cm were significantly lower than those of the control treatment (P < 0.05). The soil diurnal temperature range was ditch-buried return 20 cm > control treatment > ditch-buried return 40 cm, when measured at a soil depth of between 0 and 15 cm. However, it was highest for the control treatment at 20 cm soil depth. In addition, ditch-buried straw return to a depth of 20 cm increased the mean daily temperature in the 0-15 cm soil layer, and ditch-buried straw return to a depth of 40 cm increased mean daily temperature in the 0-20 cm soil layer. The mean daily temperature at 20 cm soil depth of ditch-buried return to a depth of 20 cm was close to that of the control treatment. In summary, ditch-buried straw return improves soil physical properties in a rice-wheat rotation system in the Yangtze River delta agricultural regions.