Management of Nitrogen Fertilizer to Reduce the Nitrate Concentration in Leaves and to Increase Yield in Chinese Chive Cultivation on Andosol

Abstract

Fertilization methods in which the nitrate concentration in leaves is low and yield is high in the cultivation of chinese chive in an andosol were investigated. The nitrate concentration in the leaves and nitrate nitrogen (N) content in the soil rose as the N content of the basal and additional chemical fertilizer increased A total of 600 kg・a^–1 of compost with a comparatively high C/N ratio in which N was slowly mineralized, was applied, and the nitrate-N content in soil and nitrate concentration in leaves were low, and the yield was high. The nitrate-N content and available N in the soil before planting were analyzed, and the amount of N which was subtracted from the standard application amount (2 kg・a^–1 N) was applied. Furthermore, controlled-release fertilizer was additionally applied, resulting in the nitrate concentration in leaves being relatively low and the yield being high. Based on these results, we propose a fertilizer application system using 600 kg・a^–1 of compost, a reduced amount of N-based fertilizer, by analyzing the nitrate-N content and available N in the soil before planting, and the additional application of controlled-release fertilizer, as a new fertilizer management method for chinese chive in an andosol to reduce the nitrate concentration in leaves and increase the yield.