旱作条件下油菜根茬对玉米两种土传病害的生防作用

Bio-control effects of rapeseed stubbles on two soil-borne diseases of maize under dry-land planting system

为探究多熟种植模式下油菜根茬对玉米土传病害的防治效应,在湖北襄阳和甘肃甘谷两地连续进行了两年的油菜—玉米、小麦—玉米轮作试验。通过对后茬玉米接种丝黑穗病原菌和纹枯病病原菌,考察两种种植模式下后作玉米土壤养分、微生物特性、土传病害发生率以及作物产量。结果表明,油菜根茬粉碎还田提高了土壤有效氮、磷、钾的含量,在整个试验周期,土壤有机质含量显著增加;油菜茬后作土壤中的细菌数量增加,而真菌减少。调查土传病害发生情况显示,油菜根茬生物熏蒸作用降低了后作玉米两种土传病害的发生率。与小麦茬后玉米相比,油菜茬后玉米产量显著提高。说明在油菜—玉米种植模式下,油菜根茬能培肥地力、改良土壤微生物环境,而且油菜根茬所具有的生物熏蒸作用对玉米土传病害有抑制作用,有利于提高后作玉米产量。

To investigate bio - control of decomposed rape stubbles on soil - borne diseases in maize under multiple cropping pattern, alternate cropping experiments with rape - maize and wheat - maize were carried out in 2 dryland producing areas for 2 consecutive years. Soil nutrient, microbial characteristics, incidence of soil - borne diseases and crop yield were investigated by inoculation of Sphacelotheca reiliana and Rhizoctonia solani on rape stubble in these 2 cropping patterns. Results showed that available N P K nutrient in soil increased with rape stubblescrushing and returning to field continuously. Soil organic matter increased significantly during the entire experiment period. Bacteria quantity in soil increased while fungi quantity decreased. T h e occurrence of soil - borne diseasesshowed that bio - fumigation effect of rape stubble reduced incidence of these two soil - borne diseases. Compared with wheat - maize rotation pattern, maize yield in rape - maize rotation pattern w a s significantly improved, m e a n-ing that rape stubbles played an important role in fertilizing soil and improving microflora environment in soil. In addition, rape stubble had an inhibitory effect on these 2 soil - borne diseases in maize, which was conducive to improve the yield of succeeding maize.