Effects Of Different Nitrogen Application Rates And Piling Height On Ratooning Rice Yield And Nitrogen Use Efficiency

This study was conducted in Shaziling village,Heshan district,Yiyang city in 2019,The late rice variety Y liangyou 911 and middle rice variety Shen Liangyou 867 were used as materials,the head quarter set three nitrogen levels(N1,N2 and N3,respectively,165,210,255kg/hm~2),renewable season set two leave pile height(H1,H2,10 cm,35 cm)respectively,measured and analyzed the annual yield,yield composition,agronomic traits,nitrogen fertilizer utilization and other indicators of the two varieties,and studied the effects of different nitrogen application rate and pile height on the growth and yield of the two cultivars,so as to provide theoretical basis for the cultivation of the two varieties,the main results were as follows:(1)The yields of the first two seasons under different nitrogen treatments were highest under the average N3 treatment.The yield of the first two seasons of Y Liangyou 911 was increased by 1.57%and 0.77%compared to N1 and N2,and the yield of the first two seasons of Shenliangyou 867 N3 treatment increased production by 17.23%and 6.80%,respectively,compared to N1 and N2 treatments.Y Liangyou 911 and Shenliangyou 867under N3 treatment had higher effective ears per square meter and seed setting rate than N1and N2 treatments,and the spike number per ear was lower than N1 and N2 treatments.Increasing the application amount of nitrogen fertilizer promoted the transpiration rate,net photosynthesis rate,stomatal conductance of the leaves,increased the dry matter weight of the plant at the full heading stage,which was more conducive to high yield.The effect of increasing nitrogen fertilizer on plant height and spike length at mature stage was not significant.As the amount of fertilization increased,the nitrogen accumulation in the aerial parts of the two rice plants and the nitrogen requirement per 1000 kg of grain production increased,and the partial productivity of nitrogen fertilizer and the nitrogen harvest index decreased.(2)The yield of the two varieties in the regeneration season under different pile height treatments was the highest under H2 treatment,Y Liangyou 911 had the highest yield under N3H2 treatment,3982.8kg/hm~2,and Shenliangyou 867 had the highest yield under N2H2treatment,5433.2kg/hm~2.The effective panicle number and seed setting rate per square meter of the two varieties were higher than that of H1 treatment under H2 treatment,and the number of panicle grains was much higher than that of H2 treatment under H1 treatment.Piles are beneficial to the number of spikes.The transpiration rate of two varieties at the heading stage was higher under H2 treatment,which increased the dry matter quality at the heading stage to a certain extent;the plant height at maturity stage was that H1 treatment was greater than H2 treatment and ear length no obviously different.Nitrogen requirement per 1000 kg of two varieties produced under H1 treatment is more than H2 treatment.The partial productivity of nitrogen fertilizer and nitrogen harvest index are higher than H1treatment under H2 treatment,indicating that the high-retention rice pile reduces the nitrogen fertilizer requirement and is beneficial to rice.The absorption and utilization efficiency of nitrogen fertilizer.