Plant Soil Environ., 2026, 72(5):338-346 | DOI: 10.17221/524/2025-PSE

Plant phosphorus availability of pyrolysed pig slurry related to ammonium and nitrate nutritionOriginal Paper

Diedrich Steffens1, Ann-Kathrin Nimführ1, Lukas Kehm ORCID...1
1 Institute of Plant Nutrition (iFZ), Justus Liebig University, Giessen, Germany

Excessive slurry applications in regions with intensive livestock production are overloading soils with phosphates, which can lead to water pollution. Pyrolysis of pig slurry solids creates a fertiliser that is potentially efficient to store and transport, hence creating the opportunity to export it from affected regions. This study aims to quantify the plant availability of phosphorus (P) from the pyrolysed pig slurry in different soils and in combination with the nitrogen application in the form of nitrate (NO3–) and ammonium (NH4+), respectively. A pot experiment with maize seedlings (Zea mays L., cv. Amadeo) was conducted under glasshouse conditions to assess changes in plant-available phosphate from pyrolysed and freeze-dried solids in three contrasting topsoils with pH values of 5.2, 6.7 and 7.4 (in 0.01 mol/L CaCl2). In two separate positive control treatments, P was applied in the form of rock phosphate and Ca(H2PO4)2, respectively, instead of processed pig slurry. To eliminate nitrification in the treatment fertilised with NH4+, the synthetic nitrification inhibitor 3,4-dimethylpyrazol phosphate (DMPP) was utilised. The plant P availability of the pyrolysed and freeze-dried product exceeded the plant P availability of rock phosphate on all tested soils, but pyrolysis lowered it compared to the freeze-dried treatment. Furthermore, the NH4+ nutrition improved plant P availability compared to the NO3– nutrition. This indicates that pyrolysis potentially leads to the formation of tri- or octa-calcium phosphates rather than crystalline apatite and that the acidification of the rhizosphere by NH4+ nutrition led to the solubilisation of P. Pyrolysis is a promising treatment for making a plant available P fertiliser, however freeze-drying led to an even better result. For the future, both procedures need to be compared economically to achieve optimal utilisation of the scarce resource P.

Keywords: phosphorus recycling; nitrification inhibition; plant phosphorus availability

Received: November 19, 2025; Revised: May 12, 2026; Accepted: May 12, 2026; Prepublished online: May 22, 2026; Published: May 26, 2026  Show citation

ACS AIP APA ASA Harvard Chicago Chicago Notes IEEE ISO690 MLA NLM Turabian Vancouver
Steffens D, Nimführ A, Kehm L. Plant phosphorus availability of pyrolysed pig slurry related to ammonium and nitrate nutrition. Plant, Soil and Environment. 2026;72(5):338-346. doi: 10.17221/524/2025-PSE.
Share...
Download citation
  • BibTeX (.bib)
  • Bookends (.ris)
  • EasyBib (.ris)
  • EndNote (.enw)
  • EndNote 8 (.xml)
  • ISI WoS (.isi)
  • Medlars (.medlars)
  • Mendeley (.ris)
  • MODS (.xml)
  • Papers (.ris)
  • RefWorks (.txt)
  • RefManager (.ris)
  • RIS (.ris)
  • MS Word (.xml)
  • Zotero (.ris)
    • Open full article

    References

    1. Barberis E., Ajmone Marsan F., Scalenghe R., Lammers A., Schwertmann U., Edwards A.C., Maguire R., Wilson M.J., Delgado A., Torrent J. (1996): European soils overfertilized with phosphorus: Part 1. Basic properties. Fertilizer Research, 45: 199-207. Go to original source...
    2. Benjamini Y., Hochberg Y. (1995): Controlling the false discovery rate: a practical and powerful approach to multiple testing. Journal of the Royal Statistical Society: Series B (Methodological), 57: 289-300. Go to original source...
    3. Bergmann W. (ed.). (1992): Nutritional Disorders of Plants: Development, Visual and Analytical Diagnosis. 3rd Edition. Jena, G. Fisch-er. ISBN-10: 156081358X
    4. Frick H., Bünemann E.K., Hernandez-Mora A., Eigner H., Geyer S., Duboc O., Santner J., Recena R., Delgado A., D´Oria A., Arkoun M., Tóth Z., Jauhiainen L., Ylivainio K. (2025): Bio-based fertilisers can replace conventional inorganic P fertilisers under European pedoclimatic conditions. Field Crops Research, 325: 109803. Go to original source...
    5. Gericke S., Kurmies B. (1952): Die kolorimetrische Phosphorsäurebestimmung mit Ammonium-Vanadat-Molybdat und ihre Anwen-dung in der Pflanzenanalyse. Zeitschrift für Pflanzenernährung, Düngung, Bodenkunde, 59: 235-247.
    6. Hauter R., Mengel K. (1988): Measurement of pH at the root surface of red clover (Trifolium pratense) grown in soils differing in pro-ton buffer capacity. Biology and Fertility of Soils, 5: 295-298. Go to original source...
    7. Hernandez-Mora A., Duboc O., Lombi E., Bünemann E.K., Ylivainio K., Symanczik S., Delgado A., Abu Zahra N., Nikama J., Zuin L., Doolette C.L., Eigner H., Santner J. (2024): Fertilization efficiency of thirty marketed and experimental recycled phosphorus fertiliz-ers. Journal of Cleaner Production, 467: 142957. Go to original source...
    8. Hothorn T., Bretz F., Westfall P. (2008): Simultaneous Inference in General Parametric Models. Biometrical Journal, 50: 346-363. Go to original source... Go to PubMed...
    9. Houba V.J.G., Novozamsky I., Huybregts A.W.M., Van Der Lee J.J. (1986): Comparison of soil extractions by 0.01 M CaCl2, by EUF and by some conventional extraction procedures. Plant and Soil, 96: 433-437. Go to original source...
    10. Kosegarten H., Grolig F., Wieneke J., Wilson G., Hoffmann B. (1997): Differential ammonia-elicited changes of cytosolic pH in root hair cells of rice and maize as monitored by 2[prime],7[prime]-bis-(2-carboxyethyl)-5 (and -6)-carboxyfluorescein-fluorescence ra-tio. Plant Physiology, 113: 451-461. Go to original source...
    11. Leinweber P. (1996): Phosphorus fractions in soils from an area with high density of livestock population. Zeitschrift Für Pflanzener-nährung Und Bodenkunde, 159: 251-256. Go to original source...
    12. Lenth R., Piaskowski J. (2026): emmeans: Estimated Marginal Means, aka Least-Squares Means (R package). CRAN. Available at: https://CRAN.R-project.org/package=emmeans
    13. Liu Y., Von Wirén N. (2017): Ammonium as a signal for physiological and morphological responses in plants. Journal of Experimental Botany, 68: 2581-2592. Go to original source... Go to PubMed...
    14. Mengel K. (1986): Umsatz im Boden und Ertragswirkung rohphosphathaltiger Düngemittel. Zeitschrift Für Pflanzenernährung Und Bodenkunde, 149: 674-690. Go to original source...
    15. Mengel K., Kirkby E.A. (2001): Principles of Plant Nutrition. Dordrecht, Kluwer Academic Publishers, 849. ISBN-10: 079237150X Go to original source...
    16. Nieder R., Benbi D.K., Scherer H.W. (2011): Fixation and defixation of ammonium in soils: a review. Biology and Fertility of Soils, 47: 1-14. Go to original source...
    17. Piepho H. (2018): Letters in mean comparisons: what they do and don't mean. Agronomy Journal, 110: 431-434. Go to original source...
    18. Rahmatullah, Gill M.A., Wissemeier A.H., Steffens D. (2006): Phosphate availability from phosphate rock as related to nitrogen form and the nitrification inhibitor DMPP. Journal of Plant Nutrition and Soil Science, 169: 675-678. Go to original source...
    19. R Core Team (2026): R: A Language and Environment for Statistical Computing. Vienna, R Foundation for Statistical Computing.
    20. Riley D., Barber S.A. (1971): Effect of ammonium and nitrate fertilization on phosphorus uptake as related to root-induced pH chang-es at the root-soil interface. Soil Science Society of America Journal, 35: 301-306. Go to original source...
    21. Römheld V. (1986): pH-Veränderungen in der Rhizosphäre verschiedener Kulturpflanzenarten in Abhängigkeit vom Nährstoffangebot. Kali-Briefe (Büntenhof), 18: 13-30.
    22. Schubert S., Yan F. (1997): Nitrate and ammonium nutrition of plants: effects on acid/base balance and adaptation of root cell plasma-lemma H+ ATPase. Zeitschrift Für Pflanzenernährung Und Bodenkunde, 160: 275-281. Go to original source...
    23. Schüller H. (1969): Die CAL-Methode, eine neue Methode zur Bestimmung des pflanzenverfügbaren Phosphates in Böden. Zeitschrift Für Pflanzenernährung Und Bodenkunde, 123: 48-63. Go to original source...
    24. Steckenmesser D., Vogel C., Adam C., Steffens D. (2017): Effect of various types of thermochemical processing of sewage sludges on phosphorus speciation, solubility, and fertilization performance. Waste Management, 62: 194-203. Go to original source... Go to PubMed...
    25. Vogel C., Sekine R., Huang J., Steckenmesser D., Steffens D., Huthwelker T., Borca C.N., Pradas Del Real A.E., Castillo-Michel H., Adam C. (2020): Effects of a nitrification inhibitor on nitrogen species in the soil and the yield and phosphorus uptake of maize. Science of The Total Environment, 715: 136895. Go to original source...
    26. Weber B., Stadlbauer E.A., Schlich E., Eichenauer S., Kern J., Steffens D. (2014): Phosphorus bioavailability of biochars produced by thermo-chemical conversion. Journal of Plant Nutrition and Soil Science, 177: 84-90. Go to original source...
    27. Werner W., Fritsch F., Scherer H.W. (1988): Einfluß langjähriger Gülledüngung auf den Nährstoffhaushalt des Bodens. 2. Mitteilung: Bindung und Löslichkeitskriterien der Bodenphosphate. Zeitschrift Für Pflanzenernährung Und Bodenkunde, 151: 63-68. Go to original source...

    This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International License (CC BY 4.0), which permits use, distribution, and reproduction in any medium, provided the original publication is properly cited. No use, distribution or reproduction is permitted which does not comply with these terms.


    Return to the content