The effect of nitrogen concentration on the growth and nitrogen uptake in potted miniature rose 'Nakashima 91' cultivated using the recirculating ebb and flow system
2007
Imaida, K.(Gifu Univ. (Japan)) | Nakamura, M. | Hasebe, N. | Suzuki, R. | Takahashi, A. | Fukui, H.
To examine the most suitable concentration of nitrogen in recirculating nutrient solution, the growth and total nitrogen uptake of potted miniature rose was compared under nutrient solution with 60, 75 or 90 mg/cubic dm of total nitrogen. The ratio of nitrate- to ammonium-N in recirculating solution was 2:1. Under cultivation using a nutrient solution with 60 mg/cubic dm of total nitrogen, low nitrogen content per dry weight of plants was caused by the nitrogen supply deficiency, and plant growth was retarded. Under cultivation using a nutrient solution with 90 mg/cubic dm of total nitrogen, the high concentration of nitrogen in the recirculating solution disrupted the balance of evapotranspiration and nitrogen uptake, increased the nitrate nitrogen in soil solution and inhibited water uptake due to the high osmotic potential. These results may lead to both low efficiency and low amounts of nitrogen uptake per dry weight of plant. However, under cultivation using a nutrient solution with 75 mg/cubic dm of total nitrogen, plant growth was normal, and both the efficiency of nitrogen uptake and amount of nitrogen content per plant were high. Furthermore, there was no excess cumulation of nitrogen in the soil solution as there was when nutrient solution with 90 mg/cubic dm of total nitrogen was used. These results indicated that the amount of nitrogen supplied by fertigation should be balanced to the amount of nitrogen uptake by plants. The composition of each ion in recirculating nutrient solution was not markedly changed using a nutrient solution with 75 mg/cubic dm of total nitrogen. Therefore, 75 mg/cubic dm is considered the most suitable concentration of nitrogen for cultivation of potted miniature rose using a recirculating nutrient solution.
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