Nitrogen Absorption and Utilization Characteristics of Two High-yield Winter Wheat Cultivars under Limited Irrigation and Nitrogen Supply

Irrigation-nitrogen regulation is one of the most important measures to increase crop yield in agricultural production.In order to provide theoretical basis for saving-water,high yield and efficient wheat production,two wheat cultivars,Jimai 22 and Shimai 15,were used in the experiment.Jimai 22 is a famous high yield wheat cultivar planted widely in North China.Shimai 15 is a stable yield wheat cultivar planted widely in Hebei province.The objective of this study was to investigate the N absorption and utilization characteristics in two types of winter wheat under limited irrigation and nitrogen in North China Plain.Field experiment was carried out at the Wuqiao experiment station of China Agricultural University in 2009-2010 growth seasons.Two irrigation levels were arranged was W1(spring irrigation at jointing stage) and W2(spring irrigation at jointing and anthesis stage),and two nitrogen fertilizer treatments of N1(192 kg·hm-2) and N2(270 kg·hm-2).The results showed that under W1 level,there was no significant difference for grain yield of Jimai 22 between N1 and N2 treatments,whereas for Shimai 15,higher grain yield was observed in N1 treatment than in N2;under W2 level,grain yield in N1 treatment was the highest for both cultivars.Under the same N level,grain yield in W2 treatment was the highest for both cultivars.Under different irrigation and nitrogen treatments,grain yield of Jimai 22 was higher than that of Shimai 15.Under the same irrigation level,N use efficiency and N productive efficiency in N1 treatment was the highest for both cultivars;under the same N level,N use efficiency and N productive efficiency in W2 treatment was the highest for both cultivars.Under different irrigation and nitrogen treatments,N use efficiency and N productive efficiency of Jimai 22 was higher than that of Shimai 15.Under the same irrigation level,N accumulation amount and distribution rate after anthesis in N1 treatment was the highest for both cultivars;under the same N level,N accumulation amount and distribution rate after anthesis in W2 treatment was the highest for both cultivars.Under different irrigation and nitrogen treatments,N accumulation amount and distribution rate after anthesis of Shimai 15 was higher than that of Jimai 22.Analysis of variance showed that the effects of irrigation,variety,N fertilization,nitrogen and variety interaction,N fertilization and irrigation interaction on grain yield were significant(P0.05),irrigation played greater role than N fertilization and was the dominant factor.The results suggested that under limited irrigation(W2) level,appropriate N(N1) treatment promoted the accumulation,distribution and efficient remobilization of N after anthesis,gained higher grain yield,N utilization efficiency and N productive efficiency.