Use of Recovered Struvite and Ammonium Nitrate in Fertigation in Tomato (Lycopersicum esculentum) Production for boosting Circular and Sustainable Horticulture

Mar Carreras-Sempere,Rafaela Caceres,Marc Viñas,Carmen Biel

doi:10.3390/agriculture11111063

Mar Carreras-Sempere, Rafaela Caceres + Show 2 more

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https://doi.org/10.3390/agriculture11111063

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Journal: Agriculture	Publication Date: Oct 28, 2021
Citations: 15	License type: CC BY 4.0

Affiliation: Institute of Agrifood Research and Technology

Abstract

Struvite and ammonium nitrate are products obtained from widely studied processes to remove phosphorus (P) and nitrogen (N) from waste streams. To boost circularity in horticulture, these recovered products should be applied to edible crops. Particularly, struvite has not been implemented in fertigation as the unique source of P fertilizer. Therefore, a soilless system greenhouse experiment was conducted for tomato crops during two growing seasons. This study aims to compare the agronomic and environmental effectiveness of recovered products used in a nutrient solution for fertigation (NS) to synthetic fertilizer treatment. Moreover, two different N concentrations of the NS were tested to evaluate the impact on the N-leaching. Additionally, struvite dissolution tests were performed to ensure its solubility. Satisfactory results of struvite solubilization were obtained. Results show that both nutrient-recovered products can be used as fertilizers in NS, due to their non-statistical significance in total yield production and fruit quality. However, ammonium nitrate treatment, depending on the crop variety, showed a lower marketable yield. Moreover, the variation on N concentration input exhibited leachate concentration differences, with N leached percentage values from 36 to 13%. These results give deeper insights into the future potential utilization of nutrient-recovered products and technical data to optimize fertigation strategies.

Highlights

Phosphorous (P) and nitrogen (N) are major constraints on the yield and quality of food production
Struvite dissolution assays were found to be consistent among the different struvite batches, even the different technologies implemented to recover it and influent type may affect struvite quality [26]
This study showed that struvite and ammonium nitrate products used as fertilizers in fertigation systems for tomato crops were effective in total yield and quality product compared to conventional fertilizers

Summary

Introduction

Phosphorous (P) and nitrogen (N) are major constraints on the yield and quality of food production. The production of nitrogen fertilizers through the Haber–Bosch process is associated with a negative environmental impact due to its high energy demand. Wastewater streams contain large amounts of nutrients, especially P and N, that are polluting the water bodies [2]. The production of renewable and high-quality fertilizers from waste streams should be promoted, and the products should be tested in field conditions in order to boost circularity in horticulture systems. Among the most important recovering processes, the precipitation of P as struvite (MgNH4PO4·6H2O) should be highlighted [3,4]; in the last years, the production of ammonium nitrate (AN) (or ammonium sulphate) from WWTPs through liquid–liquid membrane contactors (LLMC), where N is captured into an acid, has been investigated [5]

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