Studies on the Accumulation of Nitrate in Horticultural Products

Abstract

In the previous paper, it was reported that nitrate content in tomato fruit was influenced by each of nitrate and potassium levels in the culture solution. The present study was carried out to investigate the mutural influence of nitrate and potassium levels and effects of each of calcium, magnesium and phosphate levels combined with several combinations of nitrate and potassium levels in the culture solution on the accumulation of nitrate in tomato fruit, using Fireball variety in sand culture.Remarkable accumulation of nitrate was found in tomato fruits grown on high level of each of nitrate and potassium. However it was found that the influence of high level of nitrate on the accumulation of nitrate in the fruit had been controlled by potassium level, because the content in the fruit grown on higher level of nitrate combined with lower level of potassium had been very low. The application of low level of nitrate combined with any level of potassium decreased remarkably nitrate content in the fruit.Application of high level of calcium decreased considerably nitrate content in the fruit and when it was combined with low level of nitrate or potassium, the threatment decreased remarkably the content in the fruit.The influences of each of magnesium and phosphate levels on the accumulation of nitrate in the fruit were not clear.