A 2- crop—year (1987-88, 1989-90bxperirnent was conducted at theCollege of Agriculture,Shahid Chameran. University in Ahvaz, to derermine the effects of nitrogen fertilizer top-dressing rates on the yield and protein content of two wheat cultivars. Nitrogen was applied at the rates of 0,25, 50, 75 and 100 Kg/ga as urea Just before spike emergence. The results showed that applyingN significantly increased the yield. Maximum yield were obtained at the rates of 75 KgN/ha for Arvand (10.3 T/ha) and 100 KgN/ha for C.henab (7.69 T/ha) cultivars. Nitrogen topdressing also increased the protein contents of both cultivars. However, Arvand had lower protein content at the highest N rates due to lack of response to N fertilizers, and lodging quality. The wheat protein rates obtained in this experiment were higher than the wheat protein rates regions. This can often occur due to shortenning of grain filling period caused by early spring warm temperatures in. -semitropical regions such as Khuzestan. In such instances, application of N top—dressing not only can result in high yields, but it can also increase the protein content of .the grain
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