前言谷类作物对范围广泛的播种量的产量反应可以用一个抛物线来表示。在这个抛物线上,当产量达到最高限度之前,上升很快,随着密度的增加,开始缓慢地下降(Holliday等)。普遍的特点是,在接近最高产量时,播种量的适宜范围比较广泛。1969年Willey等描绘了一个生物曲线图,表示产量和播种量的关系。但结果不大可能说明问题。 Preface The response of grain crops to a wide range of seeding yields can be expressed as a parabola. On this parabola, it rises very fast before it reaches its maximum capacity, and starts to decline slowly as the density increases (Holliday et al.). A common feature is that the suitable range of seeding rates is wider at near-maximum yields. In 1969 Willey et al. Plotted a biological plot showing the relationship between yield and seeding volume. But the result is unlikely to explain the problem.