Abstract:

In order to explore the effects of different irrigation methods and nitrogen fertilizer management on late rice growth,development,yield formation,and nitrogen use efficiency,Y Liangyou 911 was used as test material.Two irrigation methods(W1.flooded irrigation;W2.moistening irrigation) and three nitrogen fertilizer managenments base,tiller,ear and grain fertilizer ratios(N1:5∶3∶2,N2:3∶4∶3 and N3:3∶4∶2∶1) were designed.No fertilization served as the control (CK1.flooded irrigation;CK2.moistening irrigation).Leaf area index,SPAD value of rice leaves,dry matter mass,yield formation and nitrogen use efficiency were determined under each treatment combination.The results showed that compared with W1,the LAI of rice treated with W2 was lower in the early growth stage and higher in the middle and late growth stages.The SPAD value of W1 treatment was higher,but there was no significant difference in SPAD value in the late growth period.Under the same irrigation conditions,compared with N1,N2 and N3 treatments it could delay the decline of LAI and SPAD values in the late growth period of rice.W2 treatment could significantly increase rice dry matter accumulation by 6.61%-16.37% compared with W1 treatment.Under nitrogen fertilizer treatment,the dry matter mass was higher in the early and middle stages of growth with N1,and the dry matter mass was higher in the later stages with N1 and N3.The yield increase of W2 mode was 7.59%-10.47% compared with W1 mode.The yield of W2N3 treatment was 3.24%-14.53% higher than that of other treatment.Although the effective panicle number was lower in W2N3 treatment,other yield components were increased,which resulted in higher yield.During the two years,W2N2 and W2N3 had higher values of total nitrogen accumulation and nitrogen absorption efficiency,W2N3 had higher values of nitrogen agronomic utilization,nitrogen partial productivity and nitrogen harvest index,and W1N3 had the higher value of physiological nitrogen utilization.In conclusion,irrigation methods and nitrogen management significantly affect rice yield and nitrogen uptake and utilization.The W2 (moistening irrigation) coupled with N3 (base fertilizer∶tillering fertilizer∶ear fertilizer∶grain fertilizer=3∶4∶2∶1) nitrogen management method is more conducive to rice dry matter accumulation,yield improvement and efficient use of nitrogen fertilizer,which can not only meet high yield,but also play a role in water saving.It is the best coupling method of water and fertilizer.

Key words: Rice, Irrigation method, Nitrogen management, Dry matter, Yield, Nitrogen use efficiency