Effect of Total Nitrogen Concentration of Nutrient Solution in DFT System on the Initial Growth and Nutrient Uptake of Chinese Chive (Allium tuberosum Rottler ex Spreng.)

Abstract

This study was carried out to investigate the effect of total nitrogen (N) concentration of nutrient solution on the growth and nutrient uptake of Chinese chive (Allium tuberosum Rottler ex Spreng.) and to determine the suitable N concentration for hydroponic nutrient solution. The effects of four total nitrogen concentrations (N3: 3 me/L, N6: 6 me/L, N12: 12 me/L and N24: 24 me/L, NO3-N : NH4-N = 2 : 1) on Chinese chive at the nursery stage were studied by deep flow technique (DFT) system. The results showed that the dry weight of N3 treatment was the highest and was 0.70 g/plant. The dry weight and content of potassium (K), calcium (Ca), phosphorus (P), and magnesium (Mg) decreased with the increase of total N concentration of nutrient solution. The result that the dry weight of N3 treatment was highest among the treatments demonstrated that the suitable total N concentration in nutrient solution of hydroponically cultured Chinese chive at the nursery stage was 3 me/L under the conditions of this experiment (NO3-N : NH4-N = 2 : 1), and the NH4-N, NO3-N, P, K, Ca, and Mg uptake per gram dry matter was 28.6, 36.6, 8.2, 55.2, 10.8, and 2.7 mg, respectively. It also showed that, although the NO3-N uptake per gram dry matter hardly changed in N24 treatment, the NH4-N uptake per gram dry matter in N24 treatment increased by 71.7% compared with that of N3 treatment, indicating that overdose and excessive uptake of NH4-N might be a direct reason for the dry weight reduction of Chinese chive with the elevation of N concentration of nutrient solution in the range of 3 me/L to 24 me/L.