Liebig used the image of a barrel- now called Liebig's barrel(木桶) The capacity of the barrel is limited by the length of its shortest stave(窄板) The yield potential of a crop is like a barrel with staves of unequal length. When that stave is lengthened. another one becomes the limiting factor.• Liebig used the image of a barrel— now called Liebig‘s barrel （木桶） • The capacity of the barrel is limited by the length of its shortest stave (窄板） • The yield potential of a crop is like a barrel with staves of unequal length. When that stave is lengthened, another one becomes the limiting factor