Effect Of Silicate Supply On Rice-wheat Growth,physiology And Yield Under Nighttime Warming And Simulation

The problem of global warming has received more attentions from governors and scientists in the world.The increase in nighttime temperature is greater than daytime temperature,regarded as a significant sign of warming.Rice and wheat are the main food crops in China.Temperature is a key factor affecting the growth and development of crops.Nighttime warming will have a certain effect on the growth of rice-wheat.Silicon is the beneficial element for rice-wheat.It can promote the growth of rice-wheat and increase yield However,it is not clear how silicate application will affect the production of rice-wheat under nighttime warming.In this study,field experiments were conducted to study the effects of silicate supply on rice-wheat growth,physiological properties and yield under nighttime warming.Rice and wheat yields were simulated by applying DNDC model.This study provides an experimental basis for ensuring the sustainable development of rice and wheat production through fertilization under climate change.Main results are as follows:(1)Growth and yield of rice and wheatThe rice canopy and 5cm depth soil temperature increased by 1.21? and 0.41? at night during entire rice growth period.The wheat canopy and 5 cm depth soil temperature increased by 1.56? and 0.48? at night during entire rice growth period.Nighttime warming decreased tiller number,leaf area index,chlorophyll content,biomass,effective panicles and filled grain numbers per panicle in rice.Nighttime warming decreased rice yield by 4.45%.nighttime warming increased leaf area index,chlorophyll content,plant height,biomass,effective panicles and filled grain numbers per panicle in wheat.Nighttime warming increased wheat yield by 29.33%.Silicate application increased tiller number,leaf area index,chlorophyll content,biomass and yield in rice under nighttime warming.Namely,silicate application could obviously mitigate the depressive effects of nighttime warming on growth and yield of rice.At the same time,silicate application increased the above indicators,promoting wheat growth.Silicate application increased the yields of rice and wheat by 20.90%and 15.15%,respectively,under nighttime warming(2)Physiological properties in rice and wheatNighttime warming decreased net photosynthetic rate,transpiration rate,stomatal conductivity,stomatal limitation and water use efficiency,but increased intercellular CO2 concentration during different rice growth period.Nighttime warming increased net photosynthetic rate,stomatal conductivity,stomatal limitation and water use efficiency,but decreased transpiration rate and intercellular CO2 concentration during different wheat growth period.Silicate application increased net photosynthetic rate,transpiration rate,stomatal conductivity,stomatal limitation and water use efficiency,but decreased intercellular CO2 concentration during different rice and wheat growth period under nighttime warming.Silicate application could obviously mitigate the depressive effects of nighttime warming on physiological properties of rice.(3)DNDC model simulationDNDC model was used to simulate the yields of rice and wheat in the study area.The results showed that the model well simulated the yield of rice and wheat.Compared to observation,simulation was decreased by 1.13%and 1.30%in this experiment.Sensitivity analysis showed that temperature,atmospheric background CO2 concentration and thermal degree days at maturity had great effects on rice yield.Temperature,precipitation and atmospheric background CO2 concentration had large effects on wheat yield.