Rights statement: This is the peer reviewed version of the following article:Pedersen, I. F., Sørensen, P. , Rasmussen, J. , Withers, P. J. and Rubæk, G. H. (2019), Fertilizer ammonium : nitrate ratios determine phosphorus uptake by young maize plants . J. Plant Nutr. Soil Sci.. doi:10.1002/jpln.201800553 which has been published in final form at https://onlinelibrary.wiley.com/doi/full/10.1002/jpln.201800553 This article may be used for non-commercial purposes in accordance With Wiley Terms and Conditions for self-archiving.
Accepted author manuscript, 555 KB, PDF document
Available under license: CC BY-NC: Creative Commons Attribution-NonCommercial 4.0 International License
Final published version
Research output: Contribution to Journal/Magazine › Journal article › peer-review
<mark>Journal publication date</mark> | 4/04/2019 |
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<mark>Journal</mark> | Journal of Plant Nutrition and Soil Science |
Publication Status | E-pub ahead of print |
Early online date | 4/04/19 |
<mark>Original language</mark> | English |
We investigated the interacting effects of inorganic nitrogen and the main inorganic phosphorus form in dairy manure (dicalcium phosphate, CaHPO 4 ) on growth, nutrient uptake, and rhizosphere pH of young maize plants. In a pot experiment, three levels of CaHPO 4 (0, 167, and 500 mg P pot −1 ) were combined with nitrogen (637 mg N pot −1 ) applied at five NH 4 -N : NO 3 -N ratios (0 : 100, 25 : 75, 50 : 50, 75 : 25, and 100 : 0) and a nitrification inhibitor in a concentrated layer of a typical acid sandy soil from Denmark. 15 N-labeled NH 4 -N was applied to differentiate the role of nitrification and to partition nitrogen uptake derived from NH 4 -N. Among treatments including nitrogen, shoot biomass, rooting and phosphorus uptake were significantly higher at the five-leaf stage when CaHPO 4 was applied with NH 4 -N : NO 3 -N ratios of 50 : 50 and 75 : 25. In these treatments, rhizosphere pH dropped significantly in direct proportion with NH 4 -N uptake. The fertilizers in the concentrated layer had a root-inhibiting effect in treatments without phosphorus supply and in treatments with pure NO 3 -N or NH 4 -N supply. Increased nitrogen uptake as NH 4 -N instead of NO 3 -N reduced rhizosphere pH and enhanced acquisition of applied CaHPO 4 by young maize plants, which may have positive implications for the enhanced utilization of manure phosphorus.