Abstract: A 3-year pot experiment was conducted at the experimental base of College of Resources and Environment, Hunan Agricultural University to study the impro
vement effect of different fertilization on degraded paddy soil fertility in red earth region Since 2005. All the test six fertilization measures improved the soil fertili
ty significantly. The soil organic matter content increased up to 14.0%, soil available P increased up to 39.0 mg·kg^-1, soil available K recovered to medium level (80 mg·kg^-1), but soil available N decreased except that it was maintained at the level before experiment in rice-specific fertilizer treatment. All fertilization treatments increased the soil microbes’ amount, soil microbial activity, and soil microbial biomass C, N and P, with the best effect in treatment inorganic fertilizers incorporating with organic manure. The combined application of chemical fertilizers and organic manure also increased the rice grain yield
and fertilizer agricultural use efficiency. It was suggested that applying rice-specific fertilizer in combining with organic manure could have the best impro
vement effect for the degraded paddy soil fertility resulted by long term non-fertilization.

Key words: Alkali saline soil, Amelioration, Chloris virgata, Cornstalk, Soil seed bank