大豆连作可使根腐病自然衰退

近日，中科院海伦农业生态实验站许艳丽团队在大豆连作根部病害自然衰退研究领域获得进展，相关成果发布在《 Acta Agriculturae Scandinavica, Section B — Soil & Plant Science》。

当大豆经过长期连作以后，土壤中即使存在作物病原菌，且有较适宜的气候条件和寄主，但相应作物病害可能不会发生或者发病率很低。国外有学者认为，产生并支配地球物种多样性的首要力量——“共同进化”是生成这种土壤的主要动力。在共同进化的长期作用下，抑制性土壤为病原提供相应抑制因子。

许艳丽团队选择3种不同大豆种植方式：大豆20年连作、3年连作和20年轮作（小麦—玉米—大豆），探讨长期连作对大豆根部真菌病害的影响后发现，大豆经过长期连作以后根腐病的发生降低，病原生物镰孢菌在大豆根部密度显著下降，大豆根部的生长情况也较3年连作有所改善。通过对病原物天敌微生物的分离发现，有4种微生物的分离频率显著高于其他两种种植方式，并且通过盆栽试验发现这4种微生物对大豆根腐病具有明显的抑制作用，证明了大豆田土壤经过长期连作可引起根腐病的自然衰退，且这些抑制性微生物可能是引起这种自然衰退的主要因子。（来源：中国科学报 彭科峰）

Developing suppressive soil for root diseases of soybean with continuous long-term cropping of soybean in black soil of Northeast China

Abstract Field experiments were set up in 1991 to test if suppressive soil to soybean root diseases could be developed with continuous long-term soybean cropping in black soil of Northeast China. Based on the field observation in 2007, 2009, and 2011, soybean root growth was promoted, and the severities of root disease were reduced in a field with continuous long-term cropping with soybean. Population densities of the pathogens (Fusarium spp. and Heterodera glycines) in the soybean cropping field were significantly (P < 0.05) lower than rotation of soybean with wheat or corn. Higher levels of biological control agents (Trichoderma harzianum, Pochonia chlamydosporia, or Paecilomyces lilacinus) also were found in the long-term soybean cropping field. Therefore, continuous long-term cropping of soybean in black soil of Northeast China could develop suppressive soil to soybean root diseases.

原文链接：http://www.tandfonline.com/doi/pdf/10.1080/09064710.2014.992941