Abstract: In order to explore the effect of sweet potato plantation on soil environment of coastal area in Northern Jiangsu, a field experiment with 3 concentrations of soil salt was carried out. It was shown that the growth of sweet potato was restrained with the increase of soil salt concentration. The growth of sweet potato had no difference in soils with salt concentration of 2.0-3.1 and 1.0-2.0 g·kg^-1, indicating a certain salt resistance of sweet potato. When soil salt content was increased to 3.1-4.8 g·kg^-1, the growth index of sweet potato dropped significantly. With the prolong of sweet potato growth, soil salt declined gradually, and the soil respiration intensity presented the downward trend after rising first in soils with 1.0-2.0 and 2.0-3.1 g·kg^-1 salt concentration. After harvest, soil respiration intensity was still higher than that before sweet potato plantation. During the whole growth period, soil total nitrogen content and organic content presented the downward trend after rising first, while soil total potassium content presented the upward trend after decreasing first. The greater the soil salt, the lower the soil microbial carbon content. Along with sweet potato growth, the soil microbial carbon content showed an increasing trend in soils with salt concentration of 1.0-2.0 and 2.0-3.1 g·kg^-1. Thus, sweet potato had certain salt resistance. For the coastal areas in Northern Jiangsu, sweet potato plantation could reduce soil salt content, promote the growth of microorganisms, improve soil nutrition, and significantly improve the ecological environment of saline soil, and was especially beneficial for soils with 1.0-2.0 and 2.0-3.1 g·kg^-1 salt concentration.

Key words: sweet potato, soil salinity, soil nutrients, soil microbial carbon