间作缓解蚕豆连作障碍的根际微生态效应

通过田间小区试验,研究了3个品种蚕豆(92-24、云豆324、凤豆6号)与小麦间作对蚕豆产量、枯萎病病情指数、根际镰刀菌数量、根际真菌代谢功能多样性和土壤酶活性的影响。结果表明:与单作蚕豆相比,云豆324与小麦间作(YD324/W)和凤豆6号与小麦间作(FD6/W)处理均显著提高了蚕豆地上部干重、籽粒产量和百粒重。YD324/W和FD6/W处理使蚕豆枯萎病发病初期病情指数分别降低57.14%和41.67%,镰刀菌数量分别降低32.06%和29.88%,而92-24与小麦间作(92-24/W)处理蚕豆产量、枯萎病病情指数和镰刀菌数量与单作蚕豆均无显著差异。YD324/W和FD6/W处理显著提高了蚕豆根际真菌的多样性指数和丰富度指数,并使蚕豆根际真菌的AWCD值分别比单作蚕豆提高了61.75%和46.49%;YD324/W和FD6/W处理明显改变了蚕豆根际真菌的群落结构。而92-24/W处理对蚕豆根际真菌的多样性指数、丰富度指数和AWCD值均无显著影响,也未明显改变真菌的群落结构。不同发病时期,YD324/W和FD6/W处理均显著提高了蚕豆根际土壤的蔗糖酶、脲酶和过氧化氢酶活性;而92-24/W处理蚕豆根际蔗糖酶、脲酶和过氧化氢酶活性与单作蚕豆均无显著差异。总之,小麦与不同品种蚕豆间作改变了蚕豆根际的真菌群落结构,提高了蚕豆根际真菌的活性、多样性和丰富度,提高土壤酶活性并改善蚕豆生长,增加了蚕豆产量。表明小麦与蚕豆间作改善了根际土壤的微生态环境,降低了镰刀菌的数量,缓解了蚕豆连作障碍,但蚕豆品种的差异影响间作控病效果。

Effects of cultivars and intercropping on the rhizosphere microenvironment for alleviating the impact of continuous cropping of faba bean

A field trial was conducted to investigate the effects of three different faba bean cultivars [92-24 (92-24), Yundou 324 (YD324), Fengdou 6 (FD6)]and wheat intercropping on yield, disease index of fusarium wilt, amount of Fusarium oxysporum on faba bean, functional diversity of the fungal community, and enzyme activities in the rhizosphere of faba bean. Results showed that in comparison with that of mono-cropping, aboveground dry weight,grain yield, and 100-seed weight of faba bean were significantly increased by use of YD324 with wheat intercropping (YD324/W), and by use of FD6 with wheat intercropping (FD6/W). The disease index of fusarium wilt, and the amount of Fusarium oxysporum on YD324 decreased significantly (57.14% and 32.06%, respectively) as did those of FD6 (41.67% and 29.88%, respectively) as they were intercropped with wheat, but use of 92-24 caused no significant change. The Shannon diversity index (H) and substrate richness (S) in Biolog FF microplates of YD324/W and FD6/W were significantly higher than those for faba bean from mono-cropping. In comparison with the values for mono-cropping, the average well color development value (AWCD) of faba beans with YD324/W and FD6/W was increased by 61.75% and 46.49%, respectively. The fungal communities of faba bean rhizosphere were also changed with YD324/W and FD6/W, but use of 92-24 with wheat intercropping (92-24/W) had no significant impact on H, S, AWCD value, and fungal community. During different stages of fusarium wilt occurrence in the faba beans, the activity of invertase, urease, and catalase in the faba bean rhizosphere increased with YD324/W and FD6/W, but not with 92-24/W. Faba bean with wheat intercropping could change fungal communities; increase fungal activity, Shannon diversity index, and substrate richness; and promote soil enzyme activities. It is suggested that wheat and faba bean intercropping plays an important role in rhizosphere soil microenvironment. This could reduce the amount of Fusarium oxysporum and control the build-up of soil-borne disease caused by continuous faba bean cultivation, but the effects of intercropping are influenced by the faba bean cultivars used.