Gl. Mullins et al., Effect of seed phosphorus concentration, soil pH, and soil phosphorus status on the yield of white lupin, COMM SOIL S, 32(1-2), 2001, pp. 127-137
Previous research has suggested that successful establishment of narrow-lea
f lupin (Lupinus angustifolius L.) in the field may be limited by low phosp
horus (P) content of the seed. This relationship has not been evaluated for
white lupin (Lupinus albus L.) and thus the primary objective of this stud
y was to evaluate the effect of seed P concentration on the growth of a win
ter-hardy white lupin (cultivar, "Tifwhite-78"). A large pot study was cond
ucted to evaluate the effects of lupin seed P concentration, soil pH and P
fertilizer rate on the growth of white lupin. The study was conducted using
an inherently acidic (pH 4.5), P infertile Troup loamy sand (loamy, silice
ous, thermic, Grossarenic Kandiudult). Treatments included three lupin seed
P concentrations (0.25, 0.43, and 0.91% P), two initial soil pH levels (4.
5 and 6.5) and three rates of P fertilizer (0, 50, and 100 mg P kg(-1) soil
). The test was conducted outside using pots having an inside diameter of 2
5.4 cm and a length of 67 cm and the plants were allowed to grow until phys
iological maturity. As expected, addition of P to this P deficient soil inc
reased lupin seed yield, total dry matter production of shoots and roots, a
nd the concentration of P in the various plant parts of the lupin plant. Re
sults of this study show that lupin seed yields may be affected by the conc
entration of P in the planted seed, but only under high or optimum P fertil
ity conditions. Soil pH had only minor effects on lupin seed and dry matter
production. At the highest rate of applied P ( 100 mg P kg(-1)), slightly
higher yields were observed at the lowest pH. Results of this study suggest
that low seed P concentrations should have minimal effects on the growth a
nd production of winter-hardy white lupin.