Effect of grass competition, cutting frequency, and soil type on the phosphorus response of semi-natural populations of white clover

Abstract

Abstract Eighteen white clover populations, collected from a variety of soils in both New Zealand and England, were grown at two or more phosphorus (P) levels in two pot experiments. The aim was to determine whether cutting frequency, grass competition, or soil type had an effect on the P response of white clover and on the differences between white clover populations in their response to P. There were significant cutting frequency × P interactions for shoot dry weight and % P and % nitrogen (N) content of shoot material. In one experiment there was a significant grass competition × soil × P interaction for shoot yields. Soil type and grass competition also influenced the P response of proportion of stolon and root. Populations differed in response to P in Experiment 1, but not in Experiment 2. There was no significant correlation between the P response of populations and the P status of their native soils in either experiment. In Experiment 1, companion grass species did not affect differences between po...