Research Institutes of Sweden

AGRICULTURAL

REQUIREMENTS ON P-

FERTILISERS BASED ON

WASTEWATER PRODUCTS

Lena Rodhe, Senior Researcher, Associate Professor

Gunnar Lundin, Researcher

Åsa Myrbeck, Researcher

RISE Jordbruk och livsmedel

Bank of nutrients, example:

5000 kg N/ha: fertilising with 100 –150 kg N/ha and year

2000 kg P/ha: fertilising with 20 kg P/ha and year

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The soil is the most important resource in agriculture

Ex-

changable

P

Phosphorus in soilSource: Greppa näringen; www.greppa.nu

Organic P

Sol. P

Bound in

organic matter

P

Soluable

org. P

Leakage

Org. fertilisers Mineral fertilisers

In-organic P

Mineral bound

P

Particle P

Aims and aspects for fertilizer use:

High outcome (yield, quality)

Minimal environmental impact

Low cost

Convenience

Spreading with precision

Good spreading performance:

Correct rate (kg/ha)

Even distribution (coefficient of variation, %)

Main influencing parameters:

Machine

Fertilizer

Driver

Outer circumstances (field characteristics, weather etc.)

A:Granules

B: Prills

C: Pellets

Plant nutrient products of different types according

to manufacturing process and contents

Examples: NP 11-21 N34 NPK 10-3-1

NPKS 24-4-5-3 NPKS 6-3-12-7

7

Dominating spreading technology adaped to application rates

100-500 kg/ha

Updated spreading charts are helpful, or at least descriptions of the physical

properties

9

Alternatives for P-recirculation

Sewage

sludge

Agriculture land

1

Fertiliser

industry

3 N, P, K, S

Processing P

product

2 P

Organic matter

incl. macro and

micro nutrients:

N, P, K, S etc

10

Bottlenecks/checkpoints for re-circulation of P from sewage

sludge to agriculture

Sewage

sludge

1 2 3

P P PPP P P

1. No contaminates 3. Chemical properties2. Physical properties

P

P

Bottleneck 1: No contamination with harmful components/substances for soil or crop –trust among consumers

Bottleneck 2: Physical properties suitable for agriculture technology

Bottleneck 3: Chemical properties for dosage and high crop nutrient utilisation

11

Bottlenecks for marketing products from sewage

sludge

Keep up the good work upstreams!

Certification systems help!

Processing technology for extractingnutrients should ensure no harmful by-substances.

12

Bottleneck 1: No harmful components/substances

Standardised tests of fertiliser products for spreaders:

Granule size distribution,

Bulk density

Mass flow rate

Granule strength

13

Bottleneck 2: Physical properties (Demands on

fertilisers)

Ongoing project:

’Recirculating of phosphorus from

sewage sludge into products’

Financed by: VINNOVA, SWEDEN

Struvite from Ekobalans, analysis of flowrate and bulk density

Test of spreading evenness, mineral fertilizer

Applied rate

Distance from tramline centre, meter

Spreading pattern

Test of spreading evenness, ash

Distance from tramline centre, meter

Applied rate

Spreading pattern

Spreading pattern

Today a big supply of commersial fertilisers with high and

declared concentrations of nutrient and composed

according to soil conditions and crop demands in:

Macro-nutrients N, P, K, S

Micro nutrients: Mn, Zn, B, Mo

High water soluability wanted for fast crop uptake!

However, organic matter is often missing!!

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Bottleneck 3: Commersial fertilisers have chemical properties in

accordance to crop demands (componented products)

Sugger beats

N-P-K 15-4-8

+Magnesium,

Natrium, Sulphur and

Bor

Potatoes,

Vegetables

NPK 11-5-18

+ S, B, Fe, Cu,

Mn, Mo, Zn

Grains etc.

NPK 20-7-10

Grains etc.

NPK 21-3-10

Super

phosphate

P 20

Micro

nutrients,

leaves

fertilising

On the market

there are tailor

made fertiliser

products.

The need of

nutrients

depends

mainly on crop

and soil.

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Could recycled nutrients product be

used in organic farming?

’Closing nutrient cycles in organic farming’ – summary from

EU-meeting Dec 2017 (arranged by ESPP and IFOAM EU)

Organic farming needs recycled phosphorus

Organic farmers are generally positive to acceptance of recycled nutrient products, but

with concerns of contaminants, nutrient efficiency, overall sustainability, supply

dependence…

The current regulatory contex is complex, contradictory, incoherent (between Member

States, e.g. on definitions of ’processing’ or intensive sourced manres), for recycled

products in organic farming in Europe.

Example of struvite product for approvement in organic farming….

Ongoing revision of the EU Organic Farming Regulation, the new Fertilisers Regulation

and positive policy maker approach through the Circular Economy, opportuntity to

integrate recycled nutrient products into organic farming regulation in Europe!

20SCOOP Newsletter

No pollutants

Properties comparable to existing commersial fertilisersboth physical and chemical properties, and known effect.

Available on market.

Price comparable.

In future, recirculated P (and other nutrients) from treatment plants could be included in certification systems for organic farming, environmental certifications or othersand be mandadory!

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Requirements in summary

Research Institutes of Sweden

THANK YOU!Contact information:

Lena.rodhe@ri.se

Phone: +46(0)761031333

Jordbruk och livsmedel