Nitric nitrogen content in soil and nitrate ion concentration in petiolar sap of eggplant [Solanum melongena] under drip fertigation culture
2008
Mizda, Y.(Fukuoka-ken. Agricultural Research Center, Chikushino (Japan)) | Kakoi, H. | Araki, M. | Yamamoto, T. | Watanabe, T.
This study was carried out regarding the use of the values of nitric nitrogen content in soil as well as nitrate ion concentration in petiolar sap as indicators for assessing a pertinent rate of fertilizer application for eggplants under drip fertigation culture. Here are the results. 1. The lower limit of nitric nitrogen content in soil is 30mg/kg. The upper limit of it is 60mg/kg when reduction of environmental load was considered, although the yield of the eggplant under drip fertigation culture is the same as in the customary way when the nitric nitrogen content in the soil was 480mg/kg. 2. Even though eggplants are grown under a much broader range of nitric nitrogen content in the soil, the values of the nitrate ion concentration in petiolar sap generally remained the same. When a cultivar derived from 'Chikuyo' as scion cultivar and with 'Torero' as rootstock cultivar was used, the appropriate rate of nitrate ion concentration in petiolar sap was 10,000mg/L until early April, and afterwards 12,000mg/L. 3. The value of nitrate ion concentration in petiolar sap is dependent on the rootstock of cultivar. Thus, the pertinent rate must be determined in consideration of cultivar.
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