An Appraisal of Urine Derivatives Integrated in the Nitrogen and Phosphorus Inputs of a Lettuce Soilless Cultivation System

Christophe El-Nakhel, Danny Geelen, Jolien De Paepe, Peter Clauwaert, Stefania De Pascale and Youssef Rouphael
Additional contact information
Christophe El-Nakhel: Department of Agricultural Sciences, University of Naples Federico II, 80055 Portici, Italy
Danny Geelen: Horticell Lab, Department of Plants and Crops, Ghent University, 9000 Ghent, Belgium
Jolien De Paepe: Center for Microbial Ecology and Technology (CMET), Ghent University, 9000 Ghent, Belgium
Peter Clauwaert: Center for Microbial Ecology and Technology (CMET), Ghent University, 9000 Ghent, Belgium
Stefania De Pascale: Department of Agricultural Sciences, University of Naples Federico II, 80055 Portici, Italy
Youssef Rouphael: Department of Agricultural Sciences, University of Naples Federico II, 80055 Portici, Italy

Sustainability, 2021, vol. 13, issue 8, 1-13

Abstract: Reinforcing and optimizing sustainable food production is an urgent contemporary issue. The depletion of natural mineral resources is a key problem that is addressed by recycling mined potassium and phosphorus, and nitrogen, whose production depends on very high energy input. A closed-loop approach of fertilizer use asserts the necessity for efficient management and practices of organic waste rich in minerals. Human-derived urine is an underutilized yet excellent source for nitrogen fertilizer, and, in this study, processed urine fertilizer was applied to greenhouse soilless cultivation of lettuce ( Lactuca sativa L.) cv. Grand Rapids. Biomass increase, biometric parameters, soil plant analysis development (SPAD) index, minerals, and organic acids content of lettuce were analyzed. From eight different urine fertilizer products generated, K-struvite, urine precipitate-CaO, and the liquid electrodialysis (ED) concentrate supported the growth of lettuce similar to that of commercial mineral fertilizer. ED concentrate application led to the accumulation of potassium (+17.2%), calcium (+82.9%), malate (+185.3%), citrate (+114.4%), and isocitrate (+185.7%); K-struvite augmented the accumulation of magnesium (+44.9%); and urine precipitate-CaO induced the highest accumulation of calcium (+100.5%) when compared to the control, which is an added value when supplemented in daily diet. The results underlined the potential of nitrogen- and phosphate-rich human urine as a sustainable source for the fertilization of lettuce in soilless systems.

Keywords: sustainable fertilization; nutrient recovery; K-struvite; ED concentrate; urine precipitate; source-separated urine; circular economy; food security; waste streams (search for similar items in EconPapers)
JEL-codes: O13 Q Q0 Q2 Q3 Q5 Q56 (search for similar items in EconPapers)
Date: 2021
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (5)

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