EFFECT OF N, K AND N APPLICATION TIME ON YIELD AND UPTAKE OF WHEAT PLANTS AT NORTH DELTA

A field experiment was carried out during the two successive water seasons of 2002/2003 and 2003/ 2004. The objective of this works was to study the role of N application at tillering stage and effect of K on wheat (Triticum aestivum L.) yield, uptake of N, P, K and N-recovery . The obtained results could be summarized as follows: Grain and straw yields were highly significantly increased with increasing N level up to 120 kg N/fed. (fed=4200 m 2 ) of the two studied wheat varieties. The highest mean values were 21.91and 30.0 ardab grain/fed, (ardab=150 kg) and 5.19 and 6.0 tons straw/fed. for Giza 168 and Sids7, respectively. Applications of N at tillering stage in the presence of K have a high significant effect on grain and straw yields, of the two wheat varieties. Application of N by the rates of 24, 60, 18 and 18 kg/fed. at planting, tillering, booting and milk stages dry weight of wheat plants at maturity stage recorded the highest-mean value by about 172.2 %and 198.3 % for Giza 168 and Sids7, respectively. Applying K increased dry matter at tillering stage, booting and maturity stage for Giza 168 and Sids7.However Sids7 pronounced Giza 168. N, P and K-uptake by wheat plants was increased for the two studied varieties by N application up to 120 kg N/fed and applying K. Uptake of N, P and K by Sids7 surpassed Giza 168 Increasing N from 75 to 120 kg/fed increased N-recovery and recorded the highest value at tillering stage > booting >maturity stage of the two wheat varieties. Applying N at tillering stage for Sids7, recorded high N-recovery which surpassed Giza 168 by about 18.69 %. Applying K increased nitrogen use efficiency (NUE) by about 18.21 % and 19.24 % for Giza 168 and Sids7, respectively. Increasing N from 75 to 120 kg/fed increased the crude protein content in grains by about 12.47 % and 16.2 % and applying K increased them by 5.48 and 7.06 % for Giza 168 and Sids7, respectively.