Nitrogen absorption and utilization characteristics in different wheat cultivars and its regulation effect by nitrogen fertilizer under irrigated and dryland conditions

To understand the nitrogen (N) absorption and utilization characteristics of different wheat cultivars and the regulation effects of water and N fertilizer, a drought-resistant cultivar, JM47, and a drought-sensitive cultivar, ND189, were planted under both irrigated and dryland conditions with three N concentration. The results indicated that the N accumulation in plant at different growth stages, N absorption and its corresponding ratio from anthesis to maturity in dryland were lower than those in irrigated land, but the ratio of N absorption amount from elongation stage to anthesis was higher than that in irrigated land. The pre-anthesis N translocation to grain was affected differently by drought stress in these two cultivars. As for JM47, the significant effect was observed under the N application of 140 and 280 kg hm(-2), while slight effect was for ND189. The contribution of post-anthesis N accumulation to N in grains was higher in dryland, and greater regulated by N fertilizer, especially for JM47 than ND189. N application promoted the N accumulation in plant from booting to maturity, and higher rate of N application resulted in greater positive effect. The effects of N application on N absorption and its ratio at different stages, N harvest index, and N absorption of 100 kg grains all suggested that N application could attenuate drought stress, and the regulation effect was greater for drought-tolerant than drought-sensitive cultivars. Therefore, highly drought-resistant cultivar and N application should be considered for rainfed wheat to improve the yield.