施氮和间作对蚕豆锈病发生及田间微气候的影响

为研究不同施氮水平和间作对蚕豆锈病发生及田间微气候的影响,探讨间作系统氮肥调控下田间微气候变化与蚕豆锈病发生的关系,以小麦蚕豆间作体系为研究对象,通过田间小区试验,设N₀(0 kg·hm^-2)、N₁(45 kg·hm^-2)、N₂(90 kg·hm^-2)、N₃(135 kg·hm^-2)4个氮水平,调查蚕豆锈病发病率和病情指数,测定蚕豆不同冠层的温度、相对湿度和风速。结果表明,无论单作还是间作,施氮对蚕豆产量均无显著影响,但施氮增加了蚕豆锈病的发病率和病情指数,其中发病盛期,施氮(N₁~N₃)蚕豆锈病发病率较不施氮(N₀)处理增加1.7~7个百分点,病情指数增加10.2%~143.8%,且病情指数受施氮水平的影响较发病率明显;与N₀相比,施氮使蚕豆冠层温度降低0.1~1.8℃和风速降低7.2%~80.0%,冠层相对湿度增加0.2%~19.0%。与单作相比,间作蚕豆产量平均增加34.4%。发病盛期,间作蚕豆锈病发病率降低7.510.6个百分点、病情指数降低26.9%~51.0%;整个发病期,间作蚕豆的冠层温度和风速均高于单作蚕豆,相对湿度低于单作蚕豆。相关分析表明,发病盛期和发病末期,蚕豆锈病发病率和病情指数与相对湿度呈极显著正相关,与冠层温度、风速呈极显著负相关。总体来看,施氮水平和间作模式对蚕豆产量、冠层温度、相对湿度和风速均有影响,且间作的影响大于施氮水平。综上,小麦与蚕豆间作及控制氮肥用量是改善农田小气候且有效控制蚕豆锈病发生的有效措施。本研究结果为间作系统合理施用氮肥和发挥间作控病增产优势提供了指导和理论依据。

Effects of Nitrogen Fertilizer and Intercropping on Faba Bean Rust Occurrence and Field Microclimate

To study effect of different N application levels and intercropping on occurrence of faba bean rust and field microclimate, and to explore the relationship between field microclimate change and the occurrence of faba bean rust, the wheat-bean intercropping system was studied and tested by field plot. The temperature, relative humidity and wind speed for the canopy of the plants supplied with 4 N levels N₀(0 kg·hm^-2), N₁(90 kg·hm^-2), N₂(180 kg·hm^-2), N₃(270 kg·hm^-2)] were measured to survey disease incidence and disease severity index of faba bean rust. The results showed that nitrogen application had no significant effect on the yield of faba bean, whether it was monocultured or intercropped, but the application of nitrogen increased the incidence and disease index of faba bean rust. Compared with N₀ treatment, the disease incidence and disease severity index of faba bean rust were averagely increased by 6.2%41.9% and 10.2%143.8% with N₁, N₂ and N₃ treatments in peak stage of disease prevalence, and the disease severity index was more affected by N regulation than the disease incidence. Faba bean canopy temperature and wind speed were reduced by 0.1℃1.8℃ and 7.2%80.0%, respectively, and the canopy relative humidity was increased by 0.2%19.0% with N application. Compared with monocultured faba bean, yield of intercropping was averagely increased by 35.5%, while the disease incidence and disease severity index of intercropping were averagely decreased by 25.9%38.8% and 26.9%51.0%, respectively. During the whole disease period, the canopy temperature and wind speed of the intercropping were higher than that of monocropping, and the relative humidity was significantly lower than the monocultured faba bean. The correlation analysis showed that the disease incidence and disease severity index of faba bean rust were positively correlated with relative humidity, and significantly negatively correlated with canopy temperature and wind speed in stage of peak infection and late infection. Overall, intercropping patterns and N application levels had effects on faba bean yield, canopy temperature, relative humidity and wind speed, the effects of N application level were less than intercropping. In summary, the intercropping of wheat and faba beans and the control of nitrogen fertilizer were effective measures to improve the filed microclimate and effectively control the occurrence of faba bean rust. The results of this study provide guidance and theoretical basis for rational application of N in intercropping system and the advantage of intercropping to control disease and increase yield.