Frontiers Publishing Partnerships Changes in Soil Phosphorus Pools in Long-Term Wheat-Based Rotations in Saskatchewan, Canada With and Without Phosphorus Fertilization

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Last updated 28 setembro 2024

Frontiers Publishing Partnerships Changes in Soil Phosphorus Pools in Long-Term Wheat-Based Rotations in Saskatchewan, Canada With and Without Phosphorus Fertilization

Phosphorus (P) is an essential nutrient for all organisms, and many crops require P fertilization for optimum yield. However, there are concerns about the P in agriculture, including the sustainability of phosphate sources for fertilizers and water quality problems from P loss in runoff from agricultural lands. Most crops do not use all of the P added each year as fertilizer, leaving residual soil P that could potentially be used by subsequent crops, minimizing the need for additional fertilization. However, more information is needed to understand soil residual P pools, and their availability to crops. In Swift Current, SK, Canada, a long-term study was initiated in 1967, with four wheat-based rotations [including continuous wheat (CW), fallow-wheat-wheat (FWW), fallow-wheat (FW) and lentil-wheat (WL), with P fertilization and with or without nitrogen (N) fertilization. In 1995, P fertilization ceased on subplots in the CW and FWW rotations, and in 2008 for the FW and WL rotations. This study examined changes in soil P pools (total P, organic P, and Olsen P) from 1995-2015 for CW and FWW rotations and from 2008-2016 for FW and WL rotations, plus crop yield and grain and straw N and P concentrations. Long-term P addition increased concentrations of soil total and Olsen P in FWW, CW and FW rotation, particularly in plots without N fertilization. However, calculated P depletions based on fertilizer addition and crop P removal were negative only for plots without N fertilization. Cessation of P fertilization reduced concentrations of soil total and Olsen P, especially in plots with N fertilization. Annual yields were affected more by N fertilization and precipitation than P fertilization. Grain and straw P concentrations were not significantly reduced with short-term P cessation in FW and WL rotation, but were reduced with longer-term P fertilizer cessation in FWW and CW rotations.