Fertilizer ammonium : nitrate ratios determine phosphorus uptake by young maize plants

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...