厌氧土壤灭菌法对西瓜连作土壤性质的影响

对旱田和水田西瓜连作土用厌氧土壤灭菌法(ASD)处理,分别设对照(H1和S1,H指旱田土,S指水田土)、淹水对照(H2和S2)、添加1%稻草(H3和S3)、1%稻草+0.1%硫磺(H4和S4)、1%稻草+300 mg/kg氨水(H5和S5),混匀后淹水、密封,户外处理20 d。分别测定土壤pH值、EC值、NO_3~-、NH_4~+、SO_4~(2-)和土壤可培养微生物等指标。结果表明,ASD法可显著提高土壤pH值(P0.05),淹水对照和各处理土样的pH6.5(除H4和S4的pH6.5外),均显著高于对照(P0.05);有效调节土壤EC值,旱田土的淹水对照和各处理EC值均低于对照H1(除H5高于对照H1外),水田土S2和S3的EC值低于S1,S4和S5高于S1,但淹水对照和各处理EC值与对照相比,差异不显著(P0.05);降低土壤中NO_3~-、SO_4~(2-)含量,淹水对照和各处理土样中NO_3~-含量较对照降低79.4%~99.9%,除H4和S4中SO_4~(2-)含量较对照分别增加155.7%和58.9%外,淹水对照和其它各处理土样中SO_4~(2-)含量较对照降低38.2%~91.0%;尖孢镰刀菌西瓜专化型(Fusarium Oxysporum f.sp.Niveum,FON)数量显著降低(P0.05),旱田土和水田土中FON含量与对照H1和S1相比,分别由10~5和10~4CFU/g降至10~3CFU/g(其中各旱田土样中FON含量大小依次为H4H3=H5H2H1,各水田土样中FON含量大小依次为S4S3S5S2S1)。可见,ASD法可调节西瓜连作土理化性质,抑制FON,改善退化土壤质量。

Impact on the properties of watermelon continuous cropping soil by anaerobic soil disinfestation

With the development of specialization and industrialization in watermelon production,continuous cropping watermelon is relatively common.The accumulation of NO-3 and SO42-in soil can result in the watermelon continuous cropping soil acidification,soil-borne diseases occurring frequently,seriously affecting the yield and quality of watermelon.However,the effective ways of improving the degraded soil of watermelon continuous cropping has yet to be found now.In this study,anaerobic soil disinfestation(ASD)was used to adjust the physico-chemical properties and control soil-borne pathogen Fusarium oxysporum f.sp.Niveum(FON).The soil samples were obtained from upland and paddy field of watermelon continuous cropping soil and divided into 5 groups respectively,and each group had fifteen replicates.The weight of each sample was equal to 3 kg dry soil,treated as follows:control(non-amended and non-flooded);flooded control(non-amended but flooded alone);added rice straw(at a ratio of 1％dry soil weight,the same as below)and flooded;added rice straw and sulphur(at a rate of 0.1％dry soil weight)and flooded;added rice straw and ammonia water at a rate of 300 mg/kg dry soil weight and flooded,and then sealed and treated outdoors for 20 days.Results showed that pH values in treated soil samples sharply ranged from acidic to nearly neutral(P<0.05).The pH values of flooded controls and the treatments of the soil sample were all greater than 6.5 except that the pH of the treatment added rice straw and sulphur was less than 6.5,which was significantly higher than that of controls(P < 0.05).The soil EC values can be effectively adjusted,and the EC values of flooded controls and all the treatments of upland field soil were all less than those in H1.The soil EC values of S2 and S3 in paddy field soil were below S1,and the EC values of S4 and S5 were higher than those in S1,while the EC values of the flood controls and all the treatments were no significant difference(P> 0.05)compared with the controls.The contents of NO-3 and SO2-4 decreased,and especially the concentration of NO-3 decreased significantly(P<0.05)by ASD way.The contents of NO-3 in flood controls and the treatments of soil samples decreased by 79.4％to 99.9％than the control.The contents of SO42-in the soil samples of treatments added rice straw and sulphur were respectively increased by 155.7％and 58.9％than control,while the contents of SO2-4 in soil samples of the flooded controls and other treatments decreased by 38.2％to 91.0％compared with the control.The number of FON in treated soil was observably decreased from 105CFU/g(upland)and 104CFU/g(paddy field)to 103CFU/g(Including the size of contents of FON took on the order of H4