Determining water requirment for wheat (alamot Co.) with deferent level of nitrogen and potash fertilizers

increasingly population, need to food and limitation of water resources have caused that water world be clear more than ever. So that yield per unit of consumed water have been more important than yield per unit of area. Therefore the aim of resercher is increased of water use efficiency by prepar use of water and fertilizers. A field experiment was conducted during 1376-78 at lorestan agriculture reserch center (khoramabad) station to study the interaction of irrigation levels and nitrogen and potasium fertilizers on wheat (Co. Alamot) yield and yield components. The experiment was laid down with 5 irrigation levels (I1 , I2 , I3 , I4 , I5 ) based on estimate of water requirment of wheat for khoramabad by SWRI vis 1.5 WR. 1 WR. 0.75 WR and 0.5 WR and nitrogen levels were 100 kg/ha less than recommend value (N1), Recommend value (N2), 100 kg/ha more than recommended value (N3), and k levels were recommend value (K1), 200 kg/ha more than recommend value (K2), and 400 kg/ha more than recommended value. Recommended value were determined based on soil testing and critical levels. The experiment was laid out in split-plot factorial RCBD with all combination of irrigation and potasium levels in main plots and N levels in sub plot with 3 replication. In total two years, 1943.5, 2388.5 , 2833.5 , 3278.5 and 3723.5 m3 /ha ( 57.9 , 71.1 , 94.3 , 97.6 and 110.8 percent of water requirment ) were applied for irrigation treatments respectively. Results indicated that there was significant differences in grain yield (P%5) between irrigation treatment in first year where as no significant difference was observed between treatments as well as interaction between irigation level and fertilizer levels. In second year (1377-78), There was significant differences between irrigation, and interaction between irrigation level and K levels in grain yield. Treatment I4 with 2084 m3/ha applied water and yield of 3997 kg/ha, and I5 with 2835 m3/ha and yield of 5717 kg/ha had highest grain yield in first and second year respectivly. Water use efficeincy in second year was better than first year, and in any cases water use efficiency was increased by decreasing appliyed water. Due to high available K in soils, there were no significant differences between K levels in grain and strow yield and kernel weight in both two years. N had favorable effects on protein content in first and second year. Where as K had only good effect in first year. N had no significant effect on grian yield in both of two years but it increased strow yield in first year.