Slide 10: Slope: Rain Use Efficiency (g/m2/mm)
The linear grass production versus rainfall relation has two parameters: a slope and intercept. The slope is called the Rain Use Efficiency. It is approximately inversely linearly related to the sand content of the soil. Mechanistically, it is probably more correct to say that it is directly and linearly related to the (clay+silt) content of the soil, and the relationship shown above follows from the fact that sand+silt+clay=100%.