THE EFFECT OF OPTIMUM LEVELS OF NITROGEN AND PHOSPHATE FERTILIZATION ON YIELD AND ITS COMPONENTS OF WHEAT CROP (TRITICUM AESTIVUM L.) GROWN IN GYPSIFEROUS SOIL .

Abstract

The aim of this experiment to find the optimum levels of fertilizer to elemental nitrogen and phosphorus for wheat grown in a gypsiferous soil (Field of college of Agriculture / Tikrit University).A factorial experiment was conducted in the season 2012-2013 to grow wheat variety ( Sham 6 ),in a Randomized Complete Block Design RCBD with three replicates . The Experiment consisted of tow factors viz: nitrogen fertilization and phosphorus fertilization. Nitrogen fertilizer was applied in five levels of N viz: (160, 200, 240, 280 and 320 k g N. ha-1) symbolized as ( N1, N2, N3, N4 and N5 )as urea (46N%) at two equal doses the first was at cropping and the second was at tillering stage. Phosphate fertilizer was applied in five levels of P viz: (20, 40, 60 , 80 and 100 kg P ha-1 )symbolized as ( P1, P2, P3, P4 and P5 ).as triple superphosphate TSP (21% P). Potassium was applied before cropping at a rate (160 kg k. ha-1 ) as potassium sulfate K2SO4 (43% K) to all experimental units equally. Yield components charterers had studied,The interaction between nitrogen fertilizer and phosphate fertilizer caused a significant increase in grain yield. The highest grain yield was( 4282 kg grain ha-1 )at the treatment N4P5 , which did not differ from N4P4, the treatment N5P5 was superior in straw yield Which was (9812 kg straw ha-1 ), which did not differ significantly with treatment N4P4 and N4P5,The increase in grain yield came from the effect of No. of spikes m -2 and weight of 1000 grain g-1 and No of grains per spike -1 .