重茬大豆生长发育障碍机制初探

本文从土壤养分、微生物种群数量等方面探讨了重茬大豆生长发育障碍机制,结果表明:重茬大豆生长发育障碍并非来自土壤养分的单一过度消耗。重茬大豆根际土壤放线菌数量及优势种群与正茬没有明显区别,细菌数量比玉米茬大豆多13.9％,比谷茬多14.1％,优势种群与玉米茬大豆、谷茬大豆相同。重茬大豆根际土壤真菌数量明显多于正茬,而且花期以前,重茬大豆与正茬大豆根际土壤真菌的优势种群不同,重茬大豆以镰刀菌(Fusarium)占优势,谷茬、玉米茬大豆则以青霉(Penicillum)、木霉(Trichoderma)占优势。镰刀菌对大豆根系生长发育有害,这是重茬大豆生长发育障碍的主要原因之一。

THE NATURE OF SOYBEAN-SOYBEAN CROPPING

An attempt was made to investigate the nature of soybean-soybean cropping on soil nutritions and microbes. The results show as:(1) The harmful effect of soybean-soybean cropping results from soybean roots being un-der uafavorable condition instead of over-consuming of some nutritions.(2)The actinomyces number in soybean-soybean rhizosphere soil is almost as much as that in corn-soybean and millet-soybean. The bacterium number in soybean-soybean rhizosphere soil is 13. 9% over corn-soybean, 14. 1% over millet-soybean. The superior race of actinomyces and bacteria in soybean-soybean soil is the same as that in corn-soybean and millet-soybean cropping(3)The fungus number in soybean-soybean rhizosphere soil is much more than that of corn-soybean and millet-soybean rotaion system. Fusarium is the superior rece among fungi in soybean-soybean rhizosphere soil before blooming period. Mean while, penicillium or trichoder-ma is superior race among fungi in rhizosphere soil of corn-soybean and millet-soybean.