A regional-scale soil phosphorus balance for exploring mineral fertilizer substitution

potentials – the case of Norway

Ola Stedje Hanserud1,2, Eva Brod1,3 and Helge Brattebø2

1.Norwegian Institute for Agricultural and Environmnental research (Bioforsk)2.Industrial Ecology Programme, Norwegian University of Science and Technology (NTNU)3.Norwegian University of Life Sciences (NMBU)

Main objectiveIdentifying the theoretical potentials for

substituting mineral P fertilizer with P-rich waste sources, using Norway as a case

study, disaggregated into its 19 counties

MethodSubstance flow analysis (SFA)Annual averages for 2009-2011Main P flows to and from agricultural soil, converted to tons of P

National aggregatenumbers

+

-637

-738

-443-29

-262

-304

754-2 6

-79

70

75

64 -105

-12

137

101 34

t P/yr

• Manure as only input

-637

-738

-443-29

-262

-304

754-2 6

-79

70

75

64 -105

-12

137

101 34

t P/yr

• Manure as only input

-637

-738

-443-29

-262

-304

754-2 6

-79

70

75

64 -105

-12

137

101 34

t P/yr

• Manure as only input

• 10 negative counties

-466

16

-30077

-124

-161

104897 61

1

111

305

216 106

174

249

176 71

t P/yr

Inputs:• Manure • Meat and bone meal• Full wastewater potential

• 4 negative counties

Regional importance of wastewater P (tons P/yr)

Inputs Output

Animal manure

Wastewater, potential

Meat and bone meal

Total withdrawal (yield + losses)

Share wastewater of total withdrawal

Norway 12.000 2700 350 13400 20 %

Oslo & Akershus 270 720 30 1010 71 %

Sogn og Fjordane 710 40 3 640 6 %

Assumptions

• Manure and wastewater P distributed within each county to substitute mineral P

• Balanced fertilization of crops (input = output) → overestimation of needed input

• 100% plant available P in meat and bone meal and manure

Wastewater P plant availability

1. Treatment method with certain treatment effect → total amount P in sludge2. Total amount of P in sludge → plante available P given treatment method

Treatment method Treatment effect (%)1 P-efficiency (%)*

Chemical 90 15-35 (average: 25)2

Biological 30 1003

Chemical-biological 95 15-35 (average: 25)2

Mechanic 15 100

* Compared to plant availability of mineral P fertilizer

1Berge & Mellem 2012, 2Øgaard 2013, 3Krogstad et al. 2004

Quantification plant availability

Region Tot-P in sludge (t/yr)

Plant available P (t/yr)

P-efficiency (%)

North sea counties 1435 360 25Rest of the country 425 150 35Whole country 1860 510 27

Potential for mineral P substitution with todays technology: 510 t P/yr

Potential for mineral P substitution with new technology: 2700 t P/yr

Conclusions

• Regional soil P balances indicate substitution potentials

• Great theoretical potential in replacing mineral P fertilizer

• Plant availability of recovered wastewater P differs with technology/infrastructure

• Needs to be followed up with study of feasibility– Technical/economic/environmental– Social acceptability– Drivers (prices/costs, legislation, targets)