Fig. 1. Shoot dry weight response to P, as a fraction of the maximum possible shoot dry weight for the most and least responsive B. oleracea genotypes in two experiments (F2 and G3). Values were obtained by fitting Eq. [3] to the data. P_s is the Olsen extractable soil P, P_f is the fertilizer-P application, and P_e is a measure of the plant available P in the potting mix from which P fertilizer was withheld.