Effect of Immersion in Phosphate Solution and Contact with Superphosphate on the Germination and Sprouting of Onions (<i>Allium cepa</i> L.)

Abstract

We studied the germination and sprouting of onion seeds that had been immersed in a phosphorus solution from 0 to 5.0%. In cases of localized fertilization, we hypothesized that the phosphoric acid concentration in the soil would prevent or impede germination. Furthermore, we investigated the impact of fertilization with superphosphate on the emergence of onions. Fertilizing treatment with phosphorus of 4.66 g per pot decreased the emergence rate compared with no fertilization of 7 days after seeding, but afterwards it had no negative effect. The results suggest that the effects on germination and rooting of onion seeds immersed in a phosphorus solution are limited to just after germination. Therefore, even if seeds come into contact with superphosphate with localized fertilization, the effects on the emergence of onion decline over time. When superphosphate was locally applied, at a rate of 50 to 200 kg phosphate content per ha, the emergence rate 10 days after sowing was not affected. Key Words：local