Abstract: Effects of long-term located fertilization on the yield and quality of sweetpotato in the monitoring base established in 1980 in Xuzhou were studied. The results showed that the application of organic fertilizer (M) could improve the yield more than other fertilizers, with the significant difference at P<0.01. The accumulation rates of starch and sugar under the condition of no fertilizer (CK) were faster than any other treatment with different fertilizations. The long-term fertilization was beneficial to the accumulation of starch, especially potassium(K), which was favorable for sweet potato variety with high starch. Nitrogen fertilizer(N)was useful for the C/N metabolism, but the ratio of dry matter assigned to the root was low under potassium deficiency. N could significantly increase the content of protein, which was useful for improving the quality of flesh-eating sweetpotato. There was no obvious difference in the protein content under treatments with K and phosphorus(P), while the protein content under the treatment of M was slightly lower than the treatment of NPK. In all, M was better than the other fertilizers on quality of sweet potato.

Key words: long-term fertilizer experiment, sweetpotato, yield, quality