Evaluating the Fertilising Potential of Blended Recovered Nutrients in Horticultural Growing Medium on Viola x wittrockiana L.

Nicolai D Jablonowski,Ana A Robles-Aguilar,Oliver Grunert,Erik Meers

doi:10.3390/agronomy12010182

Nicolai D Jablonowski, Ana A Robles-Aguilar + Show 2 more

Open Access

https://doi.org/10.3390/agronomy12010182

Copy DOI

Journal: Agronomy	Publication Date: Jan 12, 2022
Citations: 2	License type: CC BY 4.0

Affiliation: Forschungszentrum Jülich, Ghent University

Abstract

Viola x wittrockiana L. is an ornamental plant in high demand in horticulture. It is becoming more critical for greenhouse growers to focus on sustainable production to enhance plant quality while reducing negative environmental impacts. Therefore, assessing the effect of recycled phosphorous (P) and nitrogen (N) sources on the growth of viola could become very useful for producers in terms of sustainability. This experiment analysed the optimal fertiliser composition to grow viola using recovered fertilisers in a greenhouse trial under controlled conditions. Well-rooted viola plugs were grown in a standard peat-based growing medium. Using recycled sources of P and N as struvite and potassium struvite, ammonium sulphate, and ammonium nitrate, 14 fertiliser blends were prepared, tested, and compared with the slow-release commercial fertiliser Osmocote. Plants treated with ammonium nitrate showed healthy growth and optimal plant N concentrations. In contrast, most blends using the recovered ammonium sulphate resulted in an unacceptable increase of ammonium concentrations in the growing medium. The combination of ammonium sulphate and potassium sulphate caused an increase in the electrical conductivity in the growing medium, negatively affecting plant growth. However, blend 13 containing struvite, ammonium sulphate and potassium struvite expressed the best chemical composition with non-significant differences in the biomass from the positive controls, as it reduced the amount of potassium sulphate needed. Our results indicate that fertiliser blends containing P as struvite, N as ammonium nitrate or reduced amount of ammonium sulphate, and K as potassium struvite can substitute the use of mineral fertiliser blends to grow ornamental plant species as viola.

Highlights

Less potassium sulphate and less ammonium sulphate were needed
Plant leaves are mainly composed of organs containing several organic compounds with different C content [22]
In leaves of healthy plants, a high proportion of these Crich compounds are found compared to unhealthy or undeveloped plants [23]. This is in accordance with the shoot nutrient analyses of the plants fertilised with blends containing ammonium nitrate as the primary N source (B1, B3, B5, B7, B9, B11), which had a normal C

Summary

Introduction

The soilless culture systems (SCS) are a leading technological factor of the modern greenhouse industry to reduce fertiliser input and overall costs. In open SCS, the fertigation solution that leaches out is discharged, while in closed SCS, the solution is collected and reused. Water-based culture systems are essentially closed systems, as the nutrient solution that runs off from the root zone is difficult to control through the water retention capacity of a porous medium. Crops like viola cultivated on growing media can perform either as an open or closed soilless culture system. Without limitations in the use and type of fertilisers, leached irrigation water from these growing media-based systems containing high concentrations of nutrients results in potential eutrophication and water pollution when discharged to the environment [3,4]. Due to exceeded nitrate threshold limits in ground and surface water, fertiliser-related environmental pollution over recent years has become a subject of growing attention for the European Union and its member states [5]

Methods

Results

Discussion

Conclusion