Effects of organic fertigation on the growth, yield, sugar and inorganic content and delta 15N values of tomato
2004
Nakano, A. (National Inst. of Vegetable and Tea Science, Ano, Mie (Japan)) | Kawashima, H. | Sakuma, H. | Uehara, Y.
Summary We attempted to establish an organic fertigation system by using corn steep liquor (CSL) as liquid fertilizer, instead of the usual inorganic fertilizer on the long-term tomato 'Renaissance' cultivation. CSL is a byproduct of corn starch factories. It is viscous liquid and contains about 3% each of N, P2O5 and K2O. In the organic fertigation, oyster shell fertilizer was added as a basal dressing to compensate for the lack of calcium in CSL. Height, stem diameter and chlorophyll content of organic fertigation were the same as the ordinal inorganic fertigation methods. As a result, almost the same yield of tomato fruits with similar brix sugar and inorganic content as the ordinal inorganic fertigation were obtained by organic fertigation. After top dressing with oyster shell, the calcium contetnt of organic fertigation in the 7th and 9th cluster of tomato were increased because of the top dressing. In both the inorganic and organic fertigation, about 100mg nitrogen and 1.2L irrigation per day were appropriate doses in spring cultivation. Average d sup(15)N values of tomato in the inorganic and organic fertigation were + 1.1 permilage and + 7.4 permilage, respectively. The d sup(15)N values of fruits reflected these results of the fertilizers even in long-term cultivation. The possibility exists to apply d sup(15)N values as an indicator of organic fertigated vegetables to distinguish them from the vegetables cultivated with ordinal inorganic fertilizer.
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