Ylp. Lin et al., MARIGOLD GROWTH AND PHOSPHORUS LEACHING IN A SOILLESS MEDIUM AMENDED WITH PHOSPHORUS-CHARGED ALUMINA, HortScience, 31(1), 1996, pp. 94-98
Alumina granules charged with P were used as an amendment to improve t
he ability of a soilless medium to retain P and provide it to plants.
Commercially available alumina was acidified, saturated with P, and ev
enly distributed in a medium of peat, vermiculite, and sand to grow po
tted marigolds (Tagetes spp.) to a commercially salable stage. Marigol
ds grown in medium amended with P-charged alumina had adequate nutriti
on and similar or superior shoot growth (as measured by height, number
of branches, and flower production) and fresh and dry weights compare
d to marigolds grown using commercial fertilizer. phosphorus-charged a
lumina at 1% or 2% of total medium volume was sufficient to grow marig
olds for at least 8 weeks and substantially reduced P leaching compare
d to conventionally fertilized controls. Alumina amendments in this ra
nge did not cause Al toxicity, as evidenced in root growth and leaf Al
content.