The effect of bacterial wilt on the fertility of different textures of latosol in Hainan province (sand from Wencheng town, Wenchang city; loam from Dacheng town, Danzhou city; clay from Yongfa town, Chengmai county) was investigated. After the occurrence of bacterial wilt, the disease incidence, physicochemical indicators including pH, organic matter (OM), available nitrogen (AN), available phosphorus (AP), available potassium (AK), soil porosity (SP), bulk density (BD), mass water content (MWC) as well as enzyme activity indicators including catalase (CAT), peroxidase (POD), sucrase (SC), urease (UE) and acid phosphatase (ACP) of the soil inoculated with Ralstonia solanacearum and blank control were compared to analyze the effects of bacterial wilt on various fertility indicators. Spearman correlation analysis and redundancy analysis (RDA) were used to determine the significant indicators affected by bacterial wilt in different soil textures. The results showed that the disease incidence and severity disease index in clay were the highest among the three soil textures, while those of loam were the lowest. In the inoculation treatments, pH, AP, SP and POD of the three soil textures were lower than those of the control, while AN, AK, MWC and UE of clay inoculation treatment were higher than those of the clay control. CAT, ACP, MWC and BD of loam inoculation treatment were higher than those of the loam control. Spearman correlation analysis results showed that OM content, AP content, SP and POD of the three texture soils were negatively correlated with disease incidence; ACP, pH and disease incidence in WCS were significantly negatively correlated (P<0.05) with disease incidence; CAT and UE were significantly positively correlated (P<0.05) with disease incidence. In loam, pH, OM, POD and UE was significantly negatively correlated with disease incidence (P<0.05); while CAT and ACP were significantly positively correlated with disease incidence (P<0.05); SP and POD in clay were significantly negatively correlated with disease incidence (P<0.05); however, AK content in clay was significantly positively correlated with disease incidence (P<0.05). RDA results showed that the SP, OM content and AN content in the control and inoculation treatments were highly correlated with UE, while both SP and AK content in the control and inoculation treatments were highly correlated with ACP and CAT respectively. After the occurrence of bacterial wilt, most fertility indicators of control and inoculation treatment of sand and loam were lower than those in clay. However, soil fertility level was not a sufficient condition for bacterial wilt, but most soil fertility indicators were reduced due to the outbreak of bacterial wilt. The lower disease incidence and disease index of tomato bacterial wilt in sand than in clay may be due to the higher AP content. The reason why disease incidence and disease index of tomato bacterial wilt in loam is lower is perhaps that low pH conditions are unsuitable for the survival of bacterial wilt. Clay with the most severe bacterial wilt disease situation including pH, nitrogen level and mass water content was suitable for the growth and reproduction of bacterial wilt. The relative abundance of potential beneficial microbial communities in clay may also be lower than sand and loam. Therefore, the control measures of bacterial wilt in different soil textures should be adapted to local conditions. Meanwhile, the relevant conclusions of this study would provide a theoretical basis for establishing the control system of bacterial wilt in Hainan province in the future.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |