西瓜根际土壤酶及微生物对小麦伴生的响应

Response of soil enzymes activities and microorganism in rhizosphere of watermelon to wheat as companion crop

连作障碍是限制设施西瓜生产的重要因素,合理地运用地上部生物多样性是解决连作障碍的有效手段。为探讨连作西瓜根际土壤酶活性和微生物对小麦伴生的响应,采用连作西瓜土壤进行盆栽试验,设置D123小麦伴生西瓜、D125小麦伴生西瓜、西瓜单作和无苗对照4个处理,研究土壤酶活性、微生物区系和微生物生物量碳、氮、磷对小麦伴生的响应。结果表明,D_(123)小麦伴生处理的根际土壤微生物总数和放线菌数量分别比西瓜单作增加了45.21%和130.20%,根际土壤放线菌的比例比西瓜单作增加了7.6%;D125小麦伴生处理的根际土壤细菌数量比西瓜单作增加了40.89%,根际细菌的比例比西瓜单作增加了10.81%。同时,两种小麦伴生处理均降低了西瓜根际土壤真菌的比例,提高了西瓜根际微生物生物量碳、氮、磷含量,降低了微生物生物量碳氮比,提高了多酚氧化酶和蔗糖酶活性。可见,连作西瓜根际对小麦伴生产生了积极的响应。

Soil sickness is an important factor which limits production of watermelon. It has also been noted that using the biodiversity of the ground could reduce soil sickness. To explore the response of soil enzymes activities and microorganism in the rhizosphere of watermelon to wheat as companion crop,pot experiments were conducted to investigate the response of soil enzymes activities,microbial community structure and microbial biomass in the rhizosphere of watermelon to wheat as companion crop. The four treatments were D_（123） wheat / watermelon companion system（ D_（123））,D_（125） wheat / watermelon companion system（ D_（125））,watermelon monoculture（ CK） and no plant（ CW）. Results showed that total microbial and actinomyce population in the rhizosphere of watermelon in the D123 wheat / watermelon system were increased by 45. 21% and 130. 20%,respectively,and ratio of actinomyce was increased by7. 6% in the D123 wheat / watermelon companion system compared with watermelon monoculture. Compared with watermelon monoculture,bacteria population was increased by 40. 89% and ratio of bacteria was increased by 10. 81%in the rhizosphere of watermelon in the D_（125） wheat / watermelon companion system. Also,the microbial biomass carbon（ MBC）,microbial biomass nitrogen（ MBN） and microbial biomass phosphorus（ MBP） in the wheat / watermel-on companion systems were significantly higher than those in the watermelon monoculture system. The ratio of fungus and the value of MBC / MBN were decreased,and polyphenol oxidase and saccharase activities in the rhizosphere of watermelon were increased in the wheat / watermelon companion systems compared with watermelon monoculture. The results suggested that watermelon rhizosphere had a positive response to wheat as a companion crop.