Growth characteristics, chlorophyll content and nutrients uptake in Tetragonia decumbens Mill. cultivated under different fertigation regimes in hydroponics

Abstract

This study was designed to investigate the growth characteristics, chlorophyll content and nutritional properties of Tetragonia decumbens, an indigenous plant species of the South African Western Cape. One hundred and eight cuttings generated from a mother plant obtained from a garden were cultivated in hydroponic systems over 7 weeks. The hydroponic experiment comprised three nutrient solutions of graded concentrations (0.2, 0.1, and 0.05% w/v) of Nutrifeed fertiliser prepared in the water whereas the control had no nutrients. Soilless treatments were made of 100% silica sand medium heaped in plastic pots near the brim. Each hydroponic system was run for 2 h/week at the pH and electrical conductivities (EC) of 4.5, 5.5, 6.5, and 3.38, 2.34, 1.10 dS m–1 respectively, whereas frequencies of irrigation were set at 2 L/h for 15 min at an intermittent break of 2 h between 0900 and 1700 hours. For the first time, this study reported macronutrients and micronutrients present in dune spinach. At P < 0.05, post-harvest results showed that fertigation did not affect the macronutrients, however, micronutrients were significantly affected. Therefore, a welldrained soilless media (100% silica) with a high nutrient application (0.2% w/v), low electrical conductivities, and moderate pH levels had better results in vegetative growth and nutritional composition compared with other treatments.