Studies on the Accumulation of Nitrate in Horticultural Products

Part VII. Effects of nitrogen fertilizer on the accumulation of nitrate in tomato fruit (2)

Abstract

It is known that nitrate in tomato fruit causes heavy tin-dissolving in canned tomato juice.
In the previous paper, it was reported that the application of the top-dressing of nitrogen increased nitrate content in tomato fruit. The present study was carried out to investigate the influence of the application time of the top-dressing of nitrogen on the accumulation of nitrate in tomato fruit.
While nitrate in soil increased by the application of the top-dressing, the content varied remarkably with the time of application. Considerable amount of nitrate was detected in the fruit grown on high level of nitrate in the soil. Nitrate contents in both soil and fruit increased when the top-dressing had been applied shortly before the beginning of harvest, or three times during the growing period.