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利用人工气候箱模拟早春育秧期出现的低温天气过程,分析了二叶至三叶期水稻烂秧的生态因子。试验表明,土壤速效氮浓度低有利于减少烂秧。土壤总氮量一定,土层加厚或土壤氮浓度一定,泥层减薄都有利于减少烂秧。土壤速效氮38至168ppm以内以硝态氮为主有利于减少烂秧,土壤速效氮达168ppm时以硝态氮为主由于生理碱性反而不利。土壤氧化还原电位(Eh)下降与烂秧减少相关显著。低温开始时土壤Eh200mv以下烂秧率接近零,但土壤Eh达100mv以下时,由于还原性毒质累积,对秧苗正常生长不利。通过对主要有关生态因子的作用特点和相互关系的分析表明,这些生态因子可分成重要性不同的五个等级。这种分类同时揭示了针对这些生态因子采取的防治措施可能最大效果及其年度间的稳定性。
The artificial climatic box was used to simulate the low temperature weather process in the early seedling stage and the ecological factors of the rotten seedling in the second to third leaves stage were analyzed. Experiments show that low soil available nitrogen concentration is conducive to reducing rotten seedlings. The amount of total nitrogen in the soil, thickened soil or a certain concentration of nitrogen in the soil, thinning of the mud layer are conducive to reducing rotting seedlings. Soil available nitrogen 38 to 168ppm within the main nitrate-nitrogen is conducive to reduce the rotten seedlings, soil available nitrogen up to 168ppm when the nitrate-based due to physiological alkaline adverse. Soil redox potential (Eh) decline and rotten seedlings decreased significantly. At the beginning of low temperature, the rate of rotten seedlings below Eh200mv was close to zero, but when soil Eh reached below 100mv, the normal growth of seedlings was unfavorable due to the accumulation of reducing toxic substances. Through the analysis of the characteristics and correlations of the major ecological factors, these ecological factors can be divided into five grades with different significance. This classification also reveals the greatest possible effect of control measures taken against these ecological factors and the stability between the years.