Reusing Coir-Based Substrates for Lettuce Growth: Nutrient Content and Phytonutrients Accumulation
Rui M. A. Machado,
Isabel Alves-Pereira,
Inês Alves,
Rui M. A. Ferreira,
Nazim S. Gruda
Affiliations
Rui M. A. Machado
MED—Mediterranean Institute for Agriculture, Environment and Development & CHANGE—Global Change and Sustainability Institute, Crop Science Department, School of Sciences and Technology, University of Évora, Pólo da Mitra, Ap. 94, 7006-554 Évora, Portugal
Isabel Alves-Pereira
MED—Mediterranean Institute for Agriculture, Environment and Development & CHANGE—Global Change and Sustainability Institute, Chemistry and Biochemistry Department, School of Sciences and Technology, University of Évora, Colégio Luís António Verney, Ap. 94, 7006-554 Évora, Portugal
Inês Alves
Chemistry and Biochemistry Department, School of Sciences and Technology, University of Évora, Colégio Luís António Verney, Ap. 94, 7006-554 Évora, Portugal
Rui M. A. Ferreira
MED—Mediterranean Institute for Agriculture, Environment and Development & CHANGE—Global Change and Sustainability Institute, Chemistry and Biochemistry Department, School of Sciences and Technology, University of Évora, Colégio Luís António Verney, Ap. 94, 7006-554 Évora, Portugal
Nazim S. Gruda
Division of Horticultural Sciences, University of Bonn, Auf dem Hügel 6, 53121 Bonn, Germany
This research aimed to assess the influence of reusing coir-based substrates on growth, nutrient content, and phytonutrients accumulation in lettuce. The experiment included a new coir pith and four coir-based mixes (1) coir, biochar, and perlite; (2) coir, compost, and perlite; (3) coir, biochar, and pine bark; and (4) coir, compost, and pine bark. All mixes had been previously utilized to grow transplanted spinach and possessed identical ratios of 78:12:10% (v/v) among their components. Lettuce (Lactuca sativa L. cv. ‘Godzilla’) seedlings were transplanted into Styrofoam plant boxes. Each day, the planting boxes received a nutrient solution via drip irrigation. Plants grown in reused mixes had similar macronutrient concentrations as those grown in coir for the first time, except for N and K in the third mix. Plants grown in reused mixtures had similar yields as those in new coir. Lettuce heads yielded 4.6–4.9 kg/m2, while plants grown in reused mixtures had equal or higher total phenols than those in new coir. Ascorbic acid content was higher in plants cultivated in reused mixes. Coir-based growing media can be reused for another short-cycle crop, like lettuce, without yield loss or phytonutrients decrease.
