Nutrient solution effects on the development and yield of Anthurium andreanum Lind. in tropical soilless conditions

The fertilization of anthurium grown in soilless culture in tropical countries is often empirically based. The methods used generally lead the grower to overestimate plant needs and to apply excessive quantities of nutrients. Mineral elements, and thus money, are wasted and there is a risk of pollution of groundwater and watercourses. In order to improve our knowledge of plant requirements, we measured, over 2 1/2 years, the growth and yield of anthurium plants receiving nutrient solutions with different total nitrogen, potassium and calcium concentrations and different NH4+/NO3− ratios. Mineral analyses of plant parts, of nutrient, leachate and substrate solutions and of the solid substrate were carried out throughout plant development. Plants receiving 4.5 mmol N/l and 1.6 mmol K/l in the nutrient solution had significantly slower growth and lower yield compared to those receiving 8.9 mmol N/l and 3.2 mmol K/l. For these latter N and K concentrations, a N-NH4+/N-NO3− ratio of 0.37 and a calcium concentration of 1.15 mmol/l gave better plant growth, development and yield than a ratio of 0.24 and a calcium concentration of 2.25 mmol/l. Applying the nutrient solution containing 8.9 mmol N/l and 3.2 mmol K/l with a N-NH4+/N-NO3− ratio of 0.37 resulted in a shorter vegetative period and more and larger flower production. The calculated mineral balances of the crop showed that more than 60% of the supplied nutrients were lost in the leachate. Suitable nutrient solutions are proposed in order to match plant absorption at different crop growth stages. The volume of nutrient solution supplied can be reduced to limit the amount of leachate, but as water demand is high, there must be at least 30% of leaching to avoid salt accumulation in the substrate. Adjusting the nutrient solution volume and composition to match plant requirements is the first step for flower yield improvement, fertilizer efficiency and reduction of pollution.