强还原处理改良西瓜连作土壤

Improving quality of watermelon continuous cropping soil by reductive soil disinfestation

采用强还原土壤灭菌法(reductive soil disinfestation,RSD),对西瓜连作土壤分别添加稻草、氨水、乙酸、酒精及其不同组合,加水密封处理,通过盆栽试验对RSD处理效果进行验证。试验结果表明,强还原处理西瓜连作土壤,可调节土壤p H值和电导率(EC),除添加乙酸的土样p H值显著(P<0.05)低于对照土样p H值外,其他处理样品p H值均高于对照,各处理土样Ec值均较对照有不同程度地升高。各处理对土壤可培养微生物中的细菌含量影响不显著(P>0.05),而对真菌、放线菌和尖孢镰刀菌影响较大,尤其是添加氨水、乙酸及氨水、乙酸与稻草的组合处理土样中均未检测出真菌、放线菌和尖孢镰刀菌。盆栽试验结果表明,各处理组西瓜死亡株数和死亡率均较对照组低(其中有3组死亡率为0,2组死亡率不到7%,而对照组死亡率高达43.3%);各处理组的西瓜长势均好于对照,西瓜产量亦高于对照,有3组西瓜产量与对照差异达显著(P<0.05)水平。总体来看,RSD能有效抑制尖孢镰刀菌,调节土壤微生物组成和结构,改良西瓜连作土壤,防治西瓜连作障碍。

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 p H 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 p H 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 0mortality,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.