Effects of cultivation methods on the yield, sugar content and delta 15N value of tomato [Lycopersicon esculentum]
2005
Nakano, A. (National Inst. of Vegetable and Tea Science, Ano, Mie (Japan)) | Kawashima, H. | Watanabe, S. | Uehara, Y.
Effects of tomato cultivation methods, fertigation with different fertilizer application rates, organic fertigation using CSL (Corn Steep Liquor) and hydroponic were compared on the yield and sugar content and delta 15N value. With an increase of nitrogen application rate, 27 (I), 41 (II), 54 (III), 81 (IV) mg/plant/day, the yield increased, however sugar content was not proportionally affected by the application rate. Analysis, including organic fertigation and hydroponics, showed sugar contents were inversely proportional to the yield. The results were induced not by the kinds of nitrogen source (organic or inorganic) nor by the nitrogen application rate but by the water application rate. When the nitrogen application rate increased to around 100 mg/plant/day, delta 15N values of tomato fruits were closer to the delta 15N values of applied fertilizer's (-0.2%o). Included other results about relationship between nitrogen application rate and fruits delta 15N values, estimated application rate in which tomato plant would be able to grow without soil nitrogen, would be 110 mg/plant/day. In the inorganic fertigation, the dependence rate to soil nitrogen was estimated at 78%, 69%, 36%, 22% in I, II, III, IV treatments respectively using the two source model of delta 15N value. The higher the application rate was, the lower the dependence rate to the soil nitrogen was. Hence, soil nitrogen plays an important role in the lower application rate of nitrogen, to the increase of tomato yield.
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