Effects of Nitrogen Concentration on Growth and Nutrient Uptake of Anthurium andraeanum Lind. Cultivated in Coir under Different Seasonal Conditions

Abstract

Coir is used around the world as a cultivation medium for plants; its commercial popularity is the result of its availability, low cost, and environmentally friendly characteristics. It is used as a medium in the hydroponic cultivation of Anthurium (Anthurium andraeanum Lind.) in Taiwan and is a new source for cut flower production around the world. Little is known about the nutrient requirements of Anthurium cultivated in coir under fluctuating climatic conditions. The objective of this study was to evaluate the influences of various nitrogen (N) concentrations on the growth and nutrient uptake of Anthurium cultivated in coir under different seasonal conditions. Four levels of N concentration in nutrient solution were used: 79 mg.L-1 (NS79 treatment), 105 mg.L-1 (NS105 treatment), 158 mg.L-1 (NS158 treatment), and 210 mg.L-1 (NS210 treatment) with NS105 serving as the control. The effects of N concentration and seasonal fluctuations on Anthurium were measured in dry weight, leaf growth, flower growth, and nutrient uptake at different growth stages during the 2-year study period. The results show that the dry weight, leaf area, and flower number were higher in plants receiving NS105 and NS158 treatments than those receiving NS79 and NS210 treatments. However, the NS158-treated plants produced better quality cut flowers than the NS105-treated plants in the first year of cultivation as indicated by their wider, circular spathe. Retarded growth of NS79-treated Anthurium was the product of insufficient N supply and reduced carbon (C) assimilation. The excess supply of N in the NS210 treatment resulted in small potassium (K) and magnesium (Mg) uptakes, which in turn resulted in poor growth in the second year of cultivation. However, the nutrient supplies in the NS158 and NS210 treatments yielded better Anthurium growth during the initial stage than the NS79- or NS105-treated groups. Regardless of plant growth, flower yield, and nutrient uptake, there were significant interactions between N treatments and seasonal fluctuations in subtropical conditions during year-round cultivation. We concluded that the limiting factor in Anthurium growth and yield during the spring and summer is the N supply, whereas climate conditions are the limiting factor during the fall and winter.