Influência do azoto no crescimento da cebola antes do inicio da forma？？o do bolbo

the effect of nitrogen application prior transplanting on aboveground growth and root growth of the short- day onions (cv. mineutaka), from transplanting to bulb initiation was studied in a pot experiment. the pot experiment was carried out with ten treatments, including two soil types (clay-sandy and sandy soil) and five levels of n application (0, 10, 30, 40 and 50 kg n ha-1) applied prior transplanting. aboveground and root growth and biomass allocation (root: shoot ratio) were not significantly affected by nitrogen level or interaction nitrogen level * soil type. the residual soil inorganic n and the released n from organic matter, most nitrogen introduced by irrigation water (20 mg n plant-1), was sufficient for plant growth before bulb initiation. plant growth and biomass allocation were significantly affected by soil type. plant biomass in clay-sandy soil was 30% higher than in sandy soil. total root length of plants grown in sandy soil (43.74 m) was 2.3 times higher than in clay-sandy soil (19.26 m). root biomass, specific root length (slr) and root-shoot ratio were higher in plants grown in sandy soil.