Rice (Oryza sativa L.) yield productivity over 
time under fixed management condition is a severe 
concern for countries like Bangladesh, where rice is the 
staple food for the human being. Long term fertilization 
experiment was conducted during 1985-2007 on Chhiata 
clay loam soil (Hyperthermic Vertic Endoaquept) in 
Bangladesh, to determine the effect of native soil nutrient 
and chemical fertilization on rice productivity in dry and 
wet condition during long-term basis (23 years) and this 
phenomenon is not well studied before. This study showed 
that the mean grain yield of rice was decreased with time 
pass in all treated plots due to deficiency in native soil 
nutrient supply whereas, in the first three years it was not 
affected in both season. In the dry season the rice 
productivity was 64%and 36% of native soil nutrient and 
chemical fertilizer contribution respectively, up to seven 
years and after that the native soil nutrient contribution to 
augment the rice productivity was decreased whereas, 
fertilizer contribution was increased up to23 years. In the 
wet season for all year (1-23 years) native soil nutrient and 
fertilizer contribution were 70% and 30% respectively, for 
rice production. Our results states that mean yield 
production from 1st to7thyearwas similar in both season but 
after 23 years it was found significantly different under 
fixed fertilizer management. In case of the dry season, native soil nutrients were key factors in rice productivity up 
to 7 years, but no significant change was observed in case 
of wet season under fixed fertilizer management. 
Therefore, it could be concluded that after 7 years, the dry 
season must be changed from fixed to flexible chemical 
fertilizer management.