Moringa oleifera leaf production with NPK fertilizer and composted yard waste

Abstract, ISHS Acta Horticulturae 1253, 2019

T.N. Motis, S.M. Reader

Keywords: biomass, fertility, input, organic, inorganic, nutrients, tree

Moringa (Moringa oleifera) produces edible, nutrient-rich leaves useful for the alleviation of malnutrition. A trial was conducted in southwest Florida under subtropical conditions to determine the extent to which leaf production can be increased with fertility inputs. Moringa seeds were sown in the field on 24 March 2015, with trees spaced 1.25 m (in row) × 3.5 m (between row). The following year (9 June 2016), the trees were pruned to a height of 75 cm and fertility treatments begun. With treatments replicated three times in a split plot design, each of five trees per plot received 0 or 2 kg of composted yard waste (whole-plot factor), as well as the equivalent of 0, 25, 50, or 75 g of nitrogen (sub-plot factor) supplied with 8-2-8 (NPK + micronutrients) fertilizer. These treatments were split-applied with half of each NPK or compost rate applied six weeks apart. The first half of each split application was applied at three-month intervals that, with the exception of a winter rest period, corresponded to moringa leaf harvests. Dry leaf matter, weighed at each of six harvests (from September 2016 to November 2017), varied with NPK rate (P<0.01). Whether or not the trees received compost, dry leaf biomass (averaged over six harvests) increased linearly from 51 g tree^‑1 with no NPK to 108 g tree^‑1 with enough NPK fertilizer to supply 75 g N tree^‑1. At one or more harvests, NPK increased soil NO₃^-, K, and Mn, all of which were low at the start of the trial. NPK also increased K and Mn in moringa leaf tissue. Results showed that inorganic fertilizer with macro and micronutrients can markedly increase moringa leaf production on sandy soil.