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Abstract

A field experiment is conducted at Al – Mishkhab rice research station in Al – Najaf Governorate during summer seasons 2013 and 2014 to study the effects of organic matter and the chemical N fertilizer to reduce chemical N fertilizer and determine the best dose for both fertilizers to give the best grain yield and growth of rice (Oryza sativa L.) Amber 33 variety . Treatments include four level of organic matter ( 0 , 5 , 10 , 15 ) ton .h-1 at sub plots and three levels of nitrogen fertilizer ( 0 , 50 , 100 ) kg .N . h-1 at main plot . split is conducted with three replicates . The following results are obtained:
1-Superiority of nitrogen at 100 kg .N h-1 in grain yield ( 5480 , 5320 ) kg h-1 and the weight of 1000 grain ( 20.2 , 20.1 ) gm. and the number of grain per spike ( 170 , 159 ) and the number of spike in M2 ( 349 , 326 ) and the biological yield ( 5926 , 5041 ) kg h-1 and spike length in the second season 26.2 cm and plant height ( 143 , 135 ) cm as compared with control treatment for both seasons.
2-The organic matter at 15 ton h-1 treatment has significant effect on the plant height ( 129 , 133 ) cm and the length of spike ( 26.4 , 26.6 ) cm and biological yield ( 5655 , 5584 ) kg h-1 and grain yield ( 5072 , 5436 ) kg h-1 and the number of spike in M2 ( 322 , 362 ) as compared with control treatment of both seasons.
3-The interaction between levels of organic matter & levels of nitrogen application is affected significantly in grain yield , the number of spike and the plant height at 15 ton .h-1 and 100 kg .N.h-1 of both seasons .

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