Effects of cutting on vegetative development and biomass quality of perennial halophytes grown in saline aquaponics

Abstract

The cultivation of vascular plants in aquaculture is becoming increasingly important and saline aquaponics have been centered on plants with a short life cycle (i.e. annual species). However, the cultivation of perennial halophytes can allow to produce biomass year-round by repeated cuttings and regrowth. The present study evaluated the effects of different cutting regimes on the growth and tissue nitrogen uptake of the perennial halophyte Paspalum vaginatum and Salicornia neei cultivated in saline aquaponics. Clarified water from Litopenaeus vannamei cultivation was used as the main source of water and nutrients to grow plants established in Nutrient Film Technique (NFT). In each trial (28 days), three groups of 22 plants were established in different NFT benches and subjected to no cutting, one harvest and two harvests. Cutting regimes applied to both halophytic species did not affect the quality of recirculating water. Tillering and stem elongation of P. vaginatum had increasing trends with augment of cutting frequency. Salicornia neei cut at 28-day intervals produced a larger number of marketable size branches with less lignified shoots than non-cut plants and branchy plants cut every 14 days, which showed the smallest branch size. Individual plants of P. vaginatum and S. neei took up in their tissues between 2.27-2.45 mg/day of N and 4.59-6.43 mg/day of N, respectively. Cutting regimes did not statistically affect the accumulation of nitrogen in the biomass of either halophytic species. One harvest treatment, every 28 days, was considered the most suitable practice for aquaponics production of both halophytes.