Abstract: The results from a field experiment over thirteen years on a black soil in Northeast China indicated that nitrogen fertilizer increased crop yields by 724kg·hm^-2 per year on average,with an increase rate of 27.5%, about 9.4kg increased yield from 1kg applied N.In the early stage,the crop yields almost gave no response to phosphorus fertilizer,owing to the high level of soil available phosphorus at the begining of the experiment.The average increase of crop yields by phosphorus in thirteen years was only 241kg·hm^-2 per year,with an increase rate of 7%,about 12.7kg increased yield from 1kg applied P.Annual application of recycled pig manure made by 80% of harvested grain fed to pigs, the stolks as bedding materials could increase crop yields by 268,258, 255kg·hm^-2 per year with an increase rate of 9.8%,7.6%, 7.0%,based on no fertilizer,with N, with P, N,respectively.There was a trend that the effect of recycled manure on crop yield was gradually increased during the period of experiment,implying the existence of accumulative residual effect from the manure.

Key words: Black soil, Long term fertilization, Application of recycled nutrients, Crop yield, re-vegetation, purple soils, Hengyang., functional diversity, microbial community