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Phosphorus mining efficiency declines with decreasing soil P concentration and varies across crop species

Schelfhout, Stephanie, De Schrijver, An, Verheyen, Kris, De Beelde, Robbe, Haesaert, Geert, Mertens, Jan
International journal of phytoremediation 2018 v.20 no.9 pp. 939-946
Helianthus annuus, Lolium perenne, buckwheat, corn, crop rotation, crops, ecological restoration, flax, mining, phosphorus, phytoremediation, seeds, soil, triticale
High soil P concentrations hinder ecological restoration of biological communities typical for nutrient-poor soils. Phosphorus mining, i.e., growing crops with fertilization other than P, might reduce soil P concentrations. However, crop species have different P-uptake rates and can affect subsequent P removal in crop rotation, both of which may also vary with soil P concentration. In a pot experiment with three soil-P-levels (High-P: 125–155 mg POₗₛₑₙ/kg; Mid-P: 51–70 mg POₗₛₑₙ/kg; Low-P: 6–21 mg POₗₛₑₙ/kg), we measured how much P was removed by five crop species (buckwheat, maize, sunflower, flax, and triticale). Total P removal decreased with soil-P-level and depended upon crop identity. Buckwheat and maize removed most P from High-P and Mid-P soils and triticale removed less P than buckwheat, maize, and sunflower at every soil-P-level. The difference in P removal between crops was, however, almost absent in Low-P soils. Absolute and relative P removal with seeds depended upon crop species and, for maize and triticale, also upon soil-P-level. None of the previously grown crop species significantly affected P removal by the follow-up crop (perennial ryegrass). We can conclude that for maximizing P removal, buckwheat or maize could be grown.