Effects Of Silicon Application On Growth And Quality Of Rice And Wheat And CH₄ And N₂O Emissions From Soil Under Nighttime Warming

The greater temperature increase at night than during the day is a significant feature of climate warming.Nighttime warming can affect rice,winter wheat growth and soil CH₄ and N₂O emissions.Both rice and wheat are siliceous crops.Silicon application can promote crop growth,increase rice yield and quality,and affect CH₄and N₂O emissions from rice and wheat soils.In this paper,through field experiments,the effects of silicon application on the growth,yield and quality of rice and wheat and CH₄ and N₂O emissions from rice and wheat soil under nighttime warming were studied,to explore whether silicon application can promote the growth of rice and wheat,improve the quality and yield of rice and wheat,and alleviate the effect of nighttime warming on the comprehensive heating potential and emission intensity of rice-wheat system.The experiment was designed with two nighttime warming levels,i.e.nighttime warming?NW?and control?CK,ambient temperature?.Two silicate supply levels,i.e.control?Si0?and Si1?slag fertilizer,200 kg Si O₂/hm²?.The main findings are as follows:?1?Nighttime warming can reduce rice root vigor,tiller number,and chlorophyll content;silicon application can increase rice root vigor,tiller number,and chlorophyll content;Application of silicon can alleviate the decrease of rice root vigor,tiller number and chlorophyll content at nighttime warming.Compared with the control,nighttime warming,silicon application,nighttime warming and silicon application all increased the tiller number,plant height,chlorophyll content and leaf area index of wheat.?2?Nighttime warming can reduce the above-ground dry weight,whole plant dry weight and yield,silicon application can significantly increase the above-ground dry weight,whole plant dry weight and increase yield.The application of silicon under nighttime warming increased the dry weight of above-ground rice and whole plant by 64.14%,55.31%and 7.13%compared with that without silicon.Both nighttime warming and silicon application can increase the above-ground dry weight and yield of wheat.Application of silicon under nighttime warming could increase the dry weight and yield of wheat above the control by 33.13%and 7.54%,respectively.?3?Nighttime warming can reduce the brown rice rate,polished rice rate,polished rice rate,and starch content,and silicon application can significantly increase the rice brown rice rate,polished rice rate,polished rice rate,and amylose and total starch contents.The application of silicon can effectively alleviate the effect of night temperature increase on rice quality.Nighttime warming or applying silicon can significantly reduce the amylose content of wheat and significantly increase its amylopectin content.Application of silicon under nighttime warming could significantly reduce wheat amylose by 26.46%compared with the control,and amylopectin and total starch increased by 87.58%and 16.41%compared with the control.?4?Nighttime warming can significantly promote CH₄ emissions from paddy soil,and silicon application can significantly reduce CH₄ emissions from paddy soil.Under nighttime warming conditions,silicon application could reduce the cumulative CH₄ emissions in rice fields by 46.67%compared with non-silicon application.Both nighttime warming or silicon application can significantly promote N₂O emissions from rice fields.Under nighttime warming conditions,silicon application can increase cumulative N₂O emissions from rice fields by 40.70%compared with the control.Nighttime warming or silicon application can significantly increase the cumulative CH₄ absorption in wheat field soil.The application of silicon under nighttime warming can increase the cumulative CH₄absorption in wheat field soil by 33.39%compared with the control.Nighttime warming can significantly increase the cumulative N₂O emissions from wheat fields by 38.38%compared with the control.Silicon application has no significant effect on N₂O emissions from wheat fields.Under the condition of nighttime warming,the cumulative N₂O emission from wheat field can be significantly reduced by 10.52%compared with that without silicon application.?5?Under nighttime warming conditions,SGWP and GHGI of silicon-treated rice and wheat were significantly reduced by 32.63%and 35.90%,respectively,compared with those without silicon.The application of silicon can effectively alleviate the promotion effect of the night temperature increase on the comprehensive temperature increasing potential and emission intensity of the rice and wheat system.