Silicate Application Alleviated the Depressive Impacts of Nighttime Warming on the Rice Growth, Yield and Quality in Southern China

Nighttime warming decreased single rice production in southern China, while silicate supply increased the yield and stress resistance. It is still unclear regarding the impacts of silicate application on the growth, yield and quality in rice under nighttime warming. A field experiment was conducted to investigate the impacts of silicate application on the growth, yield and quality during rice growing period under nighttime warming. The warming was set at two levels, that is, ambient temperature (CK) and nighttime warming (NW). The open passive nighttime warming was used in this study, that is, rice canopy was covered with aluminium foil reflective film at night (19:00–6:00). Silicate fertiliser (steel slag) was applied at two levels, that is, Si₀ (0 kg SiO₂·hm⁻²) and Si₁ (200 kg SiO₂·hm⁻²). The results indicated that, compared with the control, the average nighttime temperature on rice canopy and at 5 cm soil layer increased by 0.51°C–0.59°C and 0.28°C–0.41°C during the rice growing period, respectively. Under nighttime warming, silicate supply increased the dry weight of shoot, total dry weight of the whole plant and yield by 64.1%, 55.3% and 7.1% at the filling-maturity stage, respectively. Silicate application significantly reduced dry matter translocation rate with 15%–18%, but significantly increased the root-shoot ratio with 0.39–0.41 in rice. Under nighttime warming, silicate supply significantly increased milled rice rate, head rice rate and total starch content by 2.3%, 2.5% and 41.8%, respectively. Nighttime warming reduced the yield by decreasing the number of effective panicle, seed setting rate and 1000-grain weight, but increasing empty chaff grain. Silicate supply increased the yield by increasing the number of effective panicle, filled grains per panicle, seed setting rate and 1000-grain weight, but reducing empty chaff grain. This study suggests that silicate supply can effectively alleviate the suppressive effects of nighttime warming on single rice growth, yield and quality in Southern China.