Minimising phosphorus losses from the soil matrix

Phosphorus loss from land, due to agricultural intensification, can impair water quality. The quantity lost is a function of runoff and availability, which is affected by inputs and the ability of the soil to retain P. Losses are exacerbated if surface runoff or drainage occurs soon after P inputs (e.g. fertiliser and/or manure and dung). Strategies to mitigate P losses depend on the farming system. The first step is to maintain a farm P balance (inputs–outputs) close to zero and the agronomic optimum. The next step is to use mitigation strategies in areas that lose the most P, but occupy little of the farm or catchment's area. Focusing on these areas, termed critical source areas, is more cost-effective than farm or catchment-wide strategies. However, the worry is that mitigation strategies may not keep pace with losses due to increasing intensification. Therefore, a proactive approach is needed that identifies areas resilient to P inputs and unlikely to lose P if land use is intensified.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (276 K)Download as PowerPoint slideHighlights► Agricultural intensification promotes P loss and poor P use efficiency. ► Losses are enriched in soils with poor P retention and subject to frequent runoff. ► Strategies to prevent loss need to focus on specific farming systems. ► The effectiveness of strategies is better if applied to critical source areas (CSAs), but may never reach a reference state. ► A greater focus on farming areas naturally resilient to P loss is warranted.