Potato response to struvite compared with conventional phosphorus fertilizer in Eastern Canada

In acidic soils with high phosphorus (P) fixing capacity, P application at levels higher than crop requirements is common in crops with high P demands such as potato (Solanum tuberosum L.), which could lead to eutrophication. Recycled sources of P fertilizer, such as struvite, can be efficient in meeting crop P demands while minimizing P losses. The objective of this study—conducted in four provinces over 3 yr (2016–2018, with 12 sites in total) in Eastern Canada—was to assess potato response to P fertilizer as triple superphosphate (TSP) or a mixture of TSP with struvite. Eight P treatments were applied with five increasing P rates as TSP (0, 26, 52, 79, and 105 kg P ha−1) and three treatments as a mixture of TSP and struvite (25, 50, and 75% (w/w) struvite) at a rate of 79 kg P ha−1. Phosphorus availability indices measured multiple times over the growing season were composed of Mehlich‐3 extracted P (PM3), soil P adsorbed on anion exchange membranes (PAEMs), and petiole P‐PO4 (Ppetiole) concentrations. There was a potato yield response to P inputs at all sites, with the control treatment showing lower potato yield at all sites. Potato yield, Ppetiole, PM3, and PAEMs were comparable between 100% TSP and TSP+struvite at the same rate, except at one site where struvite at a higher proportion depressed yield and was associated with lower P uptake. Overall, the use of struvite could be a sustainable mean to address long‐term globally P scarcity.