Abstract
In a field experiment on a very sandy, slightly acidic soil in Western Australia, the relationship between yield and the level of phosphorus (P) applied was measured for two lupin species. The species were Lupinus cosentinii cv. Chapman, and L. angustifolius cv. Merrit. The P was applied once only to separate plots as single superphosphate in 1985, 1986, 1987, and 1993. The yield was measured in 1993. L. cosentinii consistently produced more dry matter and seed (grain) at the lower levels of applied P, but L. angustifolius produced larger yields at the highest levels of applied P. At each level of applied P, the P concentration in dried tops was higher in L. cosentinii. Proteoid roots, found only on L. cosentinii may have enabled L. cosentinii to utilize low levels of applied P more effectively to produce larger yields.