Growth response of broom (<Emphasis Type="Italic">Cytisus scoparius</Emphasis>) growing with and without radiata pine (<Emphasis Type="Italic">Pinus radiata</Emphasis>) seedlings to different P levels in soils

A study was carried out to test the effects of three rates of TSP (triple superphosphate) (0, 50, and 100 mg·kg⁻¹ P) on growth of broom with and without radiata pine seedlings and to determine the relationships between P concentrations in the broom shoot and dry matter yields with soil plant-available P (Bray-2 P). A bulk sample of soil was collected from Kaweka forest at soil depth of 0–10 cm, in New Zealand on March 11, 2001. The forest area was not supplied with fertiliser at least 30 years. The results show that TSP application increased P availability in the soil. The P availability concentration in soil of broom with radiata pine seedlings was higher than that in soil of broom alone. Bray-2 P concentrations had a significant logarithmic relationship with P concentrations of broom shoot and an exponential relationship with dry matter weight of whole broom plant.