EFFECT OF NITROGEN, PHOSPHORUS AND SEEDING RATES ON WHEAT PRODUCTION AND WEED CONTROL IN SIWA OASIS
Journal of Plant Production
Two field experiments were carried out in Tegzerte Research Station; Desert Research Center, Tegzerte, Siwa Oasis during winter seasons of 2002/2003 and 2004/2004 years to study the effect of nitrogen fertilization levels as (0, 80 and 100 Kg N. fed-1) and phosphorus fertilization levels (0, 15 and 31Kg P205 fed -1 ) and wheat seeding rates (70, 80 or 90 kg. fed -1 ) on wheat production and weed control. Results indicated that increasing phosphorus and nitrogen fertilization levels as well as
... eding rates led to increase significantly wheat growth, yield and its components i.e (plant height, spike length, number of spiklets per spike, seed index as 1000 grain weight, number of spikes/m 2 , grain, straw and biological yields), while fresh and dry weights of associated weeds were reduced as a result of applying the treatments. On the other hand, number of tillers /plant showed significant increase as a result of elevating both nitrogen and phosphorus fertilization, while it demonstrated significant reduction by increasing seeding rates. Number of tillers per plant was significantly increased as a result of applying the following first order interactions (31 kg P205 fed -1 × 0 kg N.fed -1 ), (0 kg N.fed -1 × 90 kg grains .fed - ) and (31 kg P205 fed -1 × 90 kg grains.fed - ). All the first order interactions i.e (phosphorus × nitrogen fertilization levels), (nitrogen fertilization levels × seeding rates) and (phosphorus fertilization levels × seeding rates), increased significantly all the studied characters. Regarding the second order interaction, higher values of wheat yields and its attributes, as well as higher reduction of fresh and dry weights of associated weeds were obtained from the interaction between (31 kg P.fed -1 × 100 kg N.fed -1 ×90 kg grains.fed - ). While higher number of tillers per plant was obtained from the interaction between (31 kg P205 fed -1 × 100 kg N.fed -1 ×70 kg grains.fed - ).