Effect of Potassium and Nitrogen Fertilization on Some Macro-nutrients Utilization Efficiency by Wheat

 
TO STUDY the effect of potassium and nitrogen fertilization treatments on wheat yield, P & K uptake and P & K utilization efficiency for wheat (Triticum aestivum, L.), variety Sakha 93, two field experiments were conducted on a clay saline soil at El-Serw Agricultural Research Station, Agricultural Research Center, Egypt during 2011/2012 and 2012/2013 winter seasons. The experiments were carried out in a split plot design with four replicates. Main plots were assigned to potassium applications (0, 47.4 & 94.8 kg K ha^-1). The sub plots were divided by mineral nitrogen treatments as follows: 44.5, 89, 133.5, 178 and 214 kg N ha^-1. Wheat yield (grain & straw) and P & K-uptake by (wheat grain & straw) increased with increasing potassium rate up to 94.8 kg K ha^-1, but P & K utilization efficiency by wheat crop was decreased. Also, these results showed that 214, 178, 133.5, 89 and 44.5 kg N ha^-1, respectively gave the highest values of the previous parameters except the PU_tE and KU_tE, where the order of values was upward with the order of the previous treatments. The interaction between 94.8 kg K ha^-1 and 214 kg N ha^-1 gave the highest wheat yield (grain & straw) and P & K uptake by grain and straw and gave the lowest PU_tE and KU_tE in both seasons. So, it is preferred to add 94.8 kg K and 214 kg N ha^-1 to economic production of wheat grain and straw especially in saline soil. Also, the highest results of PU_tE and KU_tE in both seasons were obtained with interaction between 0 kg K ha^-1 and 44.5 kg N ha^-1, it indicates shortages in uptake of phosphorus & potassium with nitrogen & potassium deficiency.