Nutrient status and vegetative growth of Vanilla planifolia Jacks plants as affected by fertilization and organic substrate composition

The cultivation of vanilla (Vanilla planifolia Jacks) is promissory in Colombia, however, its nutritional requirements are currently unknown. In this study the hypothesis was that vanilla plant nutrient status and growth depends on the substrate composition and fertilization applied. Experimental plots of 0.8 x 0.8 x 0.2 m were filled out each two months with additional 10 L of a substrate containing either woodchips (WC) or coconut fiber (CF) and leaf litter (LL) in different volumetric proportions (%) (75:25, 50:50, 25:75). Four annual doses of a chemical fertilizer (grade 27-11-11) were applied: 0, 20, 60, and 140 g per plant. Results indicate that there was a highly significant (P ≤ 0.01) interaction between substrate and fertilization on plant growth. Shoot length of vanilla plants was significantly increased with the fertilization dose of 20 g per plant only in the substrates composed by 75% of either CF or WC and 25% of LL. The presence of CF produced foliar contents of P, K, Cu, Mg, and Mn significantly higher (P ≤ 0.05) than those obtained when WC was used in the substrate. On the contrary, the presence of WC in the substrate significantly (P ≤ 0.05) increased foliar N and Ca contents in respect to those levels observed with CF in the growth substrate.