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本文从作物、土壤两个系统对大豆连作效应进行了初步分析,结果表明:连作导致土壤中水解氮含量和速效钾含量降低,微量元素锌含量减少,土壤生物活性改变,磷酸酶,脲酶活性降低,根系分泌酸性有毒物质,微生物区系发生变化,真菌富集,细菌繁殖受抑制;植株冠层发育不良,植株早衰,根系不发达,根瘤量剧减,孢囊线虫病,灰斑病,根腐病严重。认为连作障碍发生机制以化学和生物因素为限制因素。
In this paper, the continuous cropping and soil systems were used to analyze the continuous cropping effect. The results showed that the continuous cropping resulted in the decrease of hydrolyzable nitrogen and available potassium in soil, the decrease of trace element zinc, the change of soil biological activity and the decrease of phosphatase and urease activities , The root exudates acidic and toxic substances, the microflora changes, the fungus is enriched and the bacterial growth is inhibited. The canopy dysplasia, the premature plant decline, the underdeveloped root system, the sharp decrease of the nodule, the cyst nematode disease, the gray leaf spot and the root Serious rot. It is considered that the mechanism of continuous cropping obstacle is limited by chemical and biological factors.