Abstract: At two fertility levels, the concentrations of phenolic acids in the field of summer corn with returning wheat residues were measured, and the growth of seedlings and the yield were investigated. The results showed that: the maximum release of the phenolic acid occurred at the 41st day after returning wheat residues. Fertilizer application could lower the content of the phenolic acid in the soil. Returning wheat residues had no obvious effects on the germination rate of the corn, but could inhibit the growth of seedlings.When no fertilizers were applied, returning wheat residues could increase the corn yield, Nand Pcontent in the seed and N and P uptake from cropland. However, the same result couldn’t be obtained when fertilizers were applied.The phenolicacids, which were produced in the process of decomposing of wheat residues, may cause such inhibitions.

Key words: peanut, salinity stress, salinity tolerance index, membership function, cluster analysis.