Use of struvite as a fertilizer that closes phosphorus cycles in horticulture

Introduction: The use of sewage sludge from wastewater treatment plants as a material with biogenic elements (N, P, K) is part of the so-called circular economy. Phosphorus constitutes one of the basic and currently limited resources having application mainly in agriculture and horticulture. Closing the phosphorus cycle in horticulture is the use as fertilizer in crop cultivation of the components contained in the sewage sludge. P recovery will contribute to phosphorus closed cycle, more sustainable development of food production systems and simultaneously reduce the negative impact on the environment (1). In order to examine the effectiveness, studies were carried out with use struvite (trade name Phosgreen) in lettuce cultivation. The issue of the research was to evaluate the value and potential properties of struvite fertilizer made from sewage sludge transformation as a source of phosphorus compare to triple superphosphate. Methods: The success of the use of struvite was confirmed by conducting own research with testing of butter lettuce (Lactuca sativa L.) under greenhouse conditions in the Research and Experimental Station of the University of Environmental and Life Sciences in Wroclaw (Psary). In a pot experiment (12 dm3) the effect struvite (STR) as a source of P for lettuce by comparing its effectiveness with that of superphosphate enriched (SUP) was conducted. The result of this experiment, showing that STR can constitute extra source of P and can constitute an attractive product for fertilizer market, with agronomic and environmental benefits. Results & Discussions: Higher but no statistically significant value of mass of lettuce leaves, number of leaves, number of dried leaves, width of the rosette and SPAD was observed in pots where struvite (STR) applied in comparison with the control object and superphosphate enriched fertilization (SUP). STR characterizes high influence on increasing lettuce yield. Hertzberger et al. (2020) (2) confirmed that plants fertilized with struvite characterizes with higher yield, phosphorus concentration and phosphorus uptake compared to commercial phosphorus fertilizers. Borowik et al. (2018) (3) stated that struvite (STR) fertilization resulted in higher yield compared to control and standard NPK fertilization treatment in grass and cereal cultivation. Conclusions: Due to the promising results of the first series with struvite and deacidified peat further experiment will be carried out on the preferred media with different doses of calcium carbonate aiming the changes of availability of phosphorus from struvite fertilization. STR fertilization indicated the potential value of P as a comparable source to triple superphosphate. The main indicator in favor of struvite use in lettuce cultivation was biomass and width rosette respectively 65.4% and 23.2% higher compared to control. Keywords: Phosphorus, Lettuce, Struvite, Mass of rosette References Cornel, P., Schaum. L.C. Phosphorus recovery from wastewater: Needs, technologies and costs. Water Science and Technology 2009: 59 (6): 1069-1076. Hertzberger, A.J. Cusick, R.D Margenot. A.J. A review and meta-analysis of the agricultural potential of struvite as a phosphorus fertilizer. Soil Sci. Soc. Am. J. 2020: 84,3, 653-671. https://doi.org/10.1002/saj2.20065 Borowik, M., Mikos-Szymańska, M.,Wyzińska, M., Zdunek,A., Schab, S. Sułek A.. Effect of struvite fertilizers on yield and structural characteristics of spring wheat. Przem. Chem. 2018: 3,463-.466. https://doi.org/10.15199/62.2018.3.2