Effects Of Nitrogen Application On C/N Ratio Of Remaining Piles In The First Season And The Seedling Development And Rice Yield In The Regeneration Season Of Ratoon Rice

In order to explore the variation of C/N ratio of piles in the first season of ratoon rice under different nitrogen application treatments and its effects on seedling and yield in the regenerated season.In this research,Meixiangzhan 2 and Yuenongsimiao were used as materials,and six kinds of nitrogen fertilization treatments in the first season and two kinds of bud-promoting treatments were designed.The experiment was carried out in 2020 in Qianshanhong Town,Datonghu District,Yiyang City,Hunan Province.The data of tillering dynamics,C/N ratio,yield and its component factors of ratoon rice under different nitrogen treatments were investigated.The main research results are as follows:1.Nitrogen application had significant effects on total carbon content,total nitrogen content and C/N ratio of remaining piles in the first season.With the increase of nitrogen application rate in the first season,the total carbon content decreased significantly,the total nitrogen content increased significantly,and the C/N ratio decreased significantly.With the application of bud promoting fertilizer,the contents of total carbon and total nitrogen increased significantly,and the ratio of carbon to nitrogen decreased significantly.2.The effect of nitrogen application on seedling growth in regeneration season was significant.Increasing the amount of nitrogen applied in the first season and the application of bud promoting fertilizer could significantly improve the seedling growth rate and the peak number of seedlings in the regeneration season.The speed of seedling growth was the fastest within 9 days after harvest in the first season.With the increase of nitrogen application rate in the first season,the seedling growth rate in the regeneration season increased by 2.2-21.2×10~4/hm~2/d,and the number of peak seedlings increased by 11.7-209.2×10~4/hm~2.With the application of bud promoting fertilizer,the seedling growth rate in regeneration season increased by 5.6-16.7×10~4/hm~2/d,and the number of peak seedlings increased by15.8-132.5×10~4/hm~2.3.Nitrogen application had significant effects on rice yield.Increasing the amount of nitrogen application in the first season can significantly improve the yield and effective panicles per unit area in the first season.The number of effective panicles per unit area in the regeneration season could be significantly increased by increasing the amount of nitrogen applied in the first season and applying bud promoting fertilizer.However,the amount of nitrogen applied in the first season had no significant effect on the yield in the regeneration season,and the application of bud promoting fertilizer could significantly increase the yield in the regeneration season.The difference of yield between different nitrogen application treatments in the first season and the regeneration season mainly came from the effective panicles per unit area,but the effective panicles per unit area in the first season were only affected by the nitrogen application rate in the first season,while the effective panicles per unit area in the regeneration season were also affected by the nitrogen application in the first season and bud promoting fertilizer.4.The total carbon content,total nitrogen content and C/N ratio of the remaining piles in the first season were significantly correlated with the seedling growth in the regeneration season.The total carbon content was significantly or extremely significantly positively correlated with the regeneration ability,the total nitrogen content was extremely significantly positively correlated with the seedling growth rate and the peak number of seedlings,and the C/N ratio was extremely significantly negatively correlated with the seedling growth rate and the peak number of seedlings.The seedling growth rate was extremely significantly positively correlated with the peak number of seedlings.The total nitrogen content and the C/N ratio in the stump of Yuenongsimiao were extremely significantly positively correlated with the regeneration ability.5.The total nitrogen content and the C/N ratio of remaining piles in the first season were significantly correlated with the yield in the regeneration season.The total nitrogen content of the remaining piles in the first season was significantly or extremely significantly positively correlated with the yield and effective panicles per unit area in the regeneration season;C/N ratio was extremely significantly negatively correlated with yield and effective panicles per unit area in regeneration season.