Abstract: The effects of organic fertilizer instead of chemical fertilizer on crop yield,potassium accumulation,utilization rate and aftereffect of potassium fertilizer in potato-wheat rotation system were studied,which could provide a theoretical basis for potassium management under the mode of organic fertilizer replacement fertilizer application.In this study,the field experiments of different levels of organic fertilizer substitution treatment in the northern foot of Yinshan Mountain were carried out to study the response of yield effect,potassium absorption and potassium fertilizer utilization efficiency to different organic fertilizer substitution treatments in potato-wheat rotation system.The results showed that potato tuber yield and wheat grain yield increased at first and then decreased with the increase of organic fertilizer substitution.The yield of organic fertilizer replacement treatment 2 （T2） was the highest,which was significantly higher than that of pure chemical fertilizer treatment （T0）.The accumulation of potassium in organic fertilizer substitution treatment 2 （T2） was significantly higher than that in pure chemical fertilizer treatment （T0） and other organic fertilizer substitution treatments in potato and wheat planting season,which indicated that proper amount of organic fertilizer substitution had the effect of increasing the yield and potassium accumulation.In potato planting season,the utilization rate of potassium fertilizer was 7.2%-38.2%;the partial productivity of potassium fertilizer was 28.7%-297.9%;the utilization rate of potassium fertilizer was 26.2%-50.9%,and the partial productivity of potassium fertilizer was 4.0%-26.7% in wheat planting season.In potato-wheat rotation system,the proportion of organic fertilizer potassium instead of fertilizer potassium should not exceed 60%.When the ratio of organic fertilizer potassium to fertilizer potassium was 30%-60%,the effect of wheat yield increase was optimal.

Key words: Potato, Wheat, Organic fertilizer, Potassium use efficiency