Abstract: In the present study, the reductive soil disinfestation (RSD) was used to improve the quality of watermelon continuous cropping soil. The watermelon continuous cropping soil samples were incorporated with rice straw, ammonia, acetic acid, alcohol or different combinations, and then were used to test the effect of RSD treatment by planting watermelon seedling. It was shown that the pH values in soil samples added with acetic acid were significantly (P<0.05) lower than those in the samples of the original soil (OS) and controls (CK), but the pH values in other treated soil samples were all higher than those in OS and CK. The values of electrical conductivity (EC) increased in all treated soil samples. All treatments had no significant influence on soil bacteria. But, Fusarium oxysporum f. sp. niveum (FON), fungi and actinomyces were not detected in the soil samples added with ammonia, ammonia plus acetic acid, ammonia plus rice straw. The results of pot experiment showed that the number of death and mortality of watermelon in all treatment groups were lower than those in the control, as there were 3 groups with 0 mortality, and other 2 groups with mortality less than 7%, while the mortality rate in the control group was 43.3%. The watermelon growth momentum in all treatment groups was obviously better than that in the control group. The watermelon yields of all the treatment groups were also higher than that of control group, and there were 3 groups with significantly (P<0.05) higher watermelon yields than that of CK. It was concluded that RSD could effectively inhibit FON, alter soil microbial composition and structure, improve soil quality, and then control the obstacle of watermelon continuous cropping soil.

Key words: reductive soil disinfestation, continuous cropping soil, organic materials