This review highlights and discusses some options that have recently become available …

• Abstract
• Introduction
• Forms of Phosphorus in Runoff
• Influence of Recent Fertilizer Application
• Overall Comments
• Differences Between Types of Phosphate Fertilizers
• Mechanisms for Managing Event-specific Losses of Phosphorus
• Conclusions
• References
• Figures
• Tables

Table 1. Phosphorus (P) losses from different land uses, related to P fertilizer application.

P loss     Land use Pathway Scale, type, measurement period P added and form Dissolved Total Applied P lost Reference, location       kg ha–1                 %   Grazed pasture surface runoff 55-m2 plots,   4 mo 0 50 (SSP)  0.91 2.43  1.57   4.64 6.1 Sharpley and Syers (1976),   New Zealand Ungrazed pasture surface runoff 41-m2 plots,   4 mo 0 50 (SSP)  0.46 1.89  0.82   3.64 5.7 Sharpley and Syers (1976),   New Zealand Ungrazed pasture surface runoff 55-m2 plots,   3 yr 0 50 (SSP)  0.47, 2.19,  1.00   4.36 6.7 Sharpley and Syers (1979b),   New Zealand Rotationally grazed   pasture surface runoff 7.8- to 11.1-ha   catchments,   1 yr 0 75 (ammonium   phosphate)  0.02 2.43  0.20   3.09 2.9 Olness et al. (1980), USA Continuously grazed   pasture surface runoff 7.8- to 11.1-ha   catchments,   1 yr 0 75 (ammonium   phosphate)  0.01 3.27  0.76   4.90 4.1 Olness et al. (1980), USA Ungrazed pasture surface runoff 41- to 55-m2   plots, 5 mo 0 50 (solid SSP)  0.28,¶ 1.71,¶  0.87   3.77 5.8 Sharpley and Syers (1983),   New Zealand       50 (liquid SSP)  0.79,¶  1.23 2.3   Grazed hill country   pasture surface and   subsurface   runoff 0.1- to 1.5-ha   catchments,   1.5 to 4.5 yr 11 64 (SSP)  0.10,¶ 0.14,¶  0.95   0.94  – – Lambert et al. (1985),   New Zealand Ungrazed pasture surface runoff   (first irrigation) 240-m2 irrigation   bays, 1 mo 0 22 – 6.00#  –   6.60 30.0 Austin et al. (1996),   Australia       44  8.70#  9.70 22.0         66 11.40#  12.90 19.5         88 (SSP) 11.50#  11.90 13.5   Grazed pasture surface and   subsurface   runoff 1-ha lysimeter   plots, 30 h 0 16 (TSP) – –  0.001 approx. 0.5 approx. 3 Haygarth and Jarvis (1997),   UK Ungrazed pasture surface runoff 150-m2 hillslope   plots, 1 wk 0 100 (DAP)  0.09 2.50  0.09   3.80 3.8 Heathwaite et al. (1998),   UK Grazed pasture surface runoff 0.37-ha irrigation   bays, 2 yr 0 44 (SSP)  6.0, 20.7,  8.1   26.7 42 Bush and Austin (1999),   Australia       44 (Prolong) 13.1,  17.7 22   Ungrazed pasture surface runoff 0.5-m2 hillslope   plots, 7.5 mo 0 35 (SSP)   0.02 0.59  0.04   0.64 1.8 Nguyen et al. (1999),   New Zealand       35 (TSP)  0.77  0.84 2.4         35 (TSP–DAPR)  0.27  0.32 0.9         35 (DAPR)  0.03  0.06 0.2   Laboratory microcosm,   sieved soil surface runoff 0.5-m2 sloped   plots, 1 mo 0 35 (SSP)  0.008 0.430  0.42   1.12 2.0 Nguyen et al. (2002),   New Zealand       35 (DAPR)  0.017  0.43  0.03   Cultivated seedbed surface runoff   (first runoff   event) 32-m2 plots,   4 mo 0 90 (TSP)  0.008 0.62  0.04   0.67 0.7 Withers et al. (2001),   UK Ungrazed pasture subsurface and   surface runoff 30-m2 lysimeter   plots, 1 wk 0 29 (TSP) – –  0.06   1.86 6.4 Preedy et al. (2001),   UK Paddy soil under   wheat subsurface and   surface runoff 30-m2 plots,   3 mo 0 20  0.03 0.04  0.25   0.39 0.7 Zhang et al. (2003),   Anzhen, China       80  0.10  0.57 0.4         160 (N–P–K + SSP)  0.28  0.82 0.4   Paddy soil under   wheat subsurface and   surface runoff 30-m2 plots,   3 mo 0 20  0.04 0.19  0.39   0.54  0.75 Zhang et al. (2003),   Changshu, China       80  0.68  1.36 1.2   160 (N–P–K + SSP)  0.94  1.94 1.2

DAP, diammonium phosphate; DAPR, direct-application phosphate rock; SSP, single superphosphate; TSP, triple superphosphate.

Total dissolved phosphorus.

Values shown are kg P ha^–1 yr^–1.

^¶ Dissolved inorganic phosphorus.

^# Estimated dissolved reactive phosphorus.

Dissolved reactive phosphorus.

Prolong is a granulated mixture of SSP and North Carolina phosphate rock, with a soluble P content of approximately 55%.

Table 2. Cumulative mean dissolved reactive phosphorus (DRP) and particulate phosphorus (PP) in 60-min simulated runoff events from unfertilized and fertilized hillslope microplots, Whatawhata, New Zealand.

Day   3 10 32 110 232 Treatment DRP PP DRP PP DRP PP DRP PP DRP PP   mg plot–1 Control  0.13 0.17  0.24 0.52  0.37 0.84  0.68 1.01  0.83 1.16 SSP 23.26 0.54 27.09 1.53 28.19 2.35 29.20 2.63 29.40 2.82 TSP/S 33.82 1.05 37.13 2.62 37.89 3.27 38.45 3.43 38.65 3.60 DAPR/TSP/S 10.48 0.52 12.09 1.43 12.51 1.99 13.17 2.23 13.38 2.43 Gafsa/S  0.17 0.22  0.47 0.89  0.76 1.31  1.18 1.52  1.39 1.70 Kosseir/S  0.23 0.33  0.45 1.02  0.75 1.42  1.13 1.58  1.29 1.73

Control, unfertilized; SSP, single superphosphate; TSP/S, triple superphosphate and elemental sulfur; DAPR/TSP/S, direct application phosphate rock blend plus triple superphosphate; Gafsa/S, Gafsa DAPR and elemental sulfur; Kosseir/S, Kosseir DAPR and elemental sulfur.

Table 3. Physicochemical characteristics of some common phosphorus fertilizers.

Fertilizer Total P P soluble in 2% citric acid P soluble in water Approximate particle density   %           g cm–3 SSP  9 90+ 80–90 1.9 TSP 20 94+ 93+ 1.9 DCP 20 95+  4–17 2.3 DAP 20 95+ 95+ 1.7 Reverted SSP  7–8 70–80 20 1.9 DAPR 12–14 30–40 1–2 3.0

DAP, diammonium phosphate; DAPR, direct-application phosphate rock; DCP, dicalcium phosphate; SSP, single superphosphate; TSP, triple superphosphate.