Effect of different rates of npk fertilization on wheat,Triticum aestivum L. under newly cul tivated sandy soil conditions

Two field experiments were carried out during 2005/2006 and 2006/2007 seasons in three locations i.e., El-Khattara and EI-Salhya, Sharkia Govemorate and El-Areish, North Sinai Governorate, Egypt to study the effect of four PK-fertilizer levels (15.5 kg P205 + 24 kg K20, 15.5 kg P205 + 48 kg K20, 31.0 kg P205 + 24 kg K20 and 31.0 kg P205 + 48 kg K20/fad.) and six N-fertilizer levels (40, 60, 80, 100, 120 and 140 kg N/fad.) on yield, yield components and yield analysis of wheat. The obtained results could be summarized as follows þ:þincreasing PK-fertilizer levels up to 31.0 kg P205 + 48 kg K20/fad. at El-Khattara and up to 31.0 kg P205 + 24 kg K20/fed. at both EI-Salhya and EI-Areish caused a significant increase in number of spikes/m. . Number of grains/spike, 1000grain weight and straw, grains and biological yields/fad. were significantly increased by adding 31.0 kg P205 + 48 kg K20/fad. at the three locations. However, the effect of PK-fertilizers on grain weight/spike at the three locations was not significant, except at EI-Khattara and EI-Salhya locations in the 1. t season which was significant. Increasing N-levels up to 140 kg N/fad. resulted in a significant increase in number of spikes/m. at the three locations, while increasing N-levels up to 120 kg N/fad. was accompanied by a significant increase in number of grains/spike at the three locations, 1000-grain weight at EI-Salhya and El-Areish and biological yield/fad. at EI-Ariesh. However, grain weight/spike at the three locations, 1000-grain weight at EI-khattara, straw and grain yields/fad. at the three locations and biological yield/fad. at El-Khattara and EI-Salhya were significantly increased when 100 kg N/fad. was applied. The significant interaction effect between the studied factors indicated that wheat plants grown at EI-Salhya and fertilized with 31.0 kg P205 + 48 kg K20 and 140 kg N/fad. gave the highest values of number of spikes/m. . Also, the highest values of 1000-grain weight, grain yield and biological yield were attained when wheat plants were fertilized with 31.0 kg P205 + 48 kg K20 and 100 kg N/fad. and this was true at EI-Ariesh location. Plants grown at El-Khattara and fertilized with 31.0 kg P205 + 24 or 48 kg K20 gave the highest straw yield/fad. when 140 kg N/fad. was applied. However, wheat plants grown at El-Khattara location surpassed those grown at El-Salhya and EI-Ariesh locations in most of studied characters. Positive and highly significant correlation coefficients were detected between grain yield/fad. and all studied characters. The path analysis revealed that the direct effect of number of spikes/m. was 63.98% being higher than that of number of grains/spike and 1000-grain weight which were 11.85 and 4.71 % of grain yield variation, respectively.