摘要: |
本文讨论了 Logistic 方程的修正问题,推导出 Logisic-r 方程和Logisic-p 方程,并利用后者拟合了呈 Sd 曲线型的菜蚜种群密度动态的田间观测数据,取得良好结果。 |
关键词: 目标曲线 种群密度 菜蚜 动态曲线 环境负荷能力 观测数据 曲线拟合 多项式 种群增长率 修正方程 |
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LOGISTIC EQUATION REVISED TO DESCRIBE DENSITY DYNAMICS OF AN APHID POPULATION ON CHINESE CABBAGE |
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Abstract: |
The density dynamic curve for aphid populations on Chinese cabbage in autumn tends to show inSdshape,which consists of two parts: S-shaped before the peak and declining after.The Sd curve can be described by a revised logistic equation,the Logistic-r equation: X=K/1+exp(p(t)) where p(t)represents the effects of environmental factors on popula- tion growth rate in time dimension. As an expendient measure,a polynomial is used to approximate the P(t),hence the Logistic-p equation: where n is the highest order... |
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