Influência do azoto no crescimento da cebola antes do inicio da formação do bolbo

Abstract

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.