Frans Aarts

Wageningen University and Research Centre (W-UR)

Plant Research International

Plantekongres 2005, Denmark

Nutrient balances:

experiences from The Netherlands

Agricultural facts

Netherlands agricultural land: 1.9

million ha animal production: 8

billion euro

24,000 dairy farms (grass, maize)

6,000 pigs/chicken farms (no land)

Denmark agricultural land: 2.7 million

ha animal production: 5 billion

euro

Agricultural facts

Netherlands agricultural land: 1.9

million ha animal production: 8

billion euro

24,000 dairy farms (grass, maize)

6,000 pigs/chicken farms (no land)

Denmark agricultural land: 2.7 million

ha animal production: 5 billion

euro

Livestock density

high very high

Manure-N (1997)

Netherlands:

- 258 kg N/ha on average

- 288 kg N/ha on dairy farms

Denmark:

- 90 kg N/ha on average

Effect of livestock density on N balance

(Denmark)

0

50

100

150

200

250

300

350

400

0 100 200 300

N i husdyrgødning til markkg N/ha

N-o

ve

rsk

ud

be

dri

ft,

kg

N/h

a

Konv. planteavl u. dyr

Konv. planteavl m. sl.svin

Konv. svin inde

Konv. svin friland

Konv. kvæg

Øko. kvæg

Øko. svin friland

Effect of livestock density on N balance (EU, le

Gall) N surplus

0

100

200

300

400

0 2000 4000 6000 8000 10000 12000 14000

Milk (kg/ha)

Intensive systems of Nor Northern Europe

Extensive systems

Intensive and sustainable systems of western France

Intensive systems of Atlantique Area

7500 kg milk= 170 kg N-manure

Effect of livestock density on N balance (le

Gall) N surplus

0

100

200

300

400

0 2000 4000 6000 8000 10000 12000 14000

Milk (kg/ha)

Intensive systems of Nor Northern Europe

Extensive systems

Intensive and sustainable systems of western France

Intensive systems of Atlantique Area

Dutch average

Effect of livestock density on N balance

N surplus/ha (= input – output)

manure-N/ha

Nitrates directive

N surplus

manure-N/ha170 kg

EU nitrates directive

190 kg

Nitrates directive N surplus

manure-N/ha170 kg

EU nitrates directive Dutch dairy farms

288 kg

190 kg

355 kg

Effect of livestock density on N surplus

N surplus

manure-N/ha

Individual farms

Effect of livestock density on N surplus

N surplus

manure-N/ha

Individual farms

On farm level: livestock density is a weak

indicator for N surplus

N-surplus as indicator for environmental

effectsQuality water

N surplus/ha

excellent

bad

N-surplus as indicator for

environmental effectsQuality water

N surplus/ha

peat, grassland

average

dry sand, arablebad

excellent

N-surplus as indicator for

environmental effects

N surplus/ha

peat, grassland

average

light sand, arable

desired

acceptable

Quality water

N-surplus as indicator for

environmental effects

N surplus/ha

peat, grassland

average

light sand, arable

desired

acceptable

At farm level N-surplus can be a good indicator for environmental

performance

Quality water

Surplus N related to nitrate leaching (light

sandy soils)

0

40

80

120

160

0 100 200 300 400

Surplus farm (kg N/ha)

(mg/l)

2000 2001 2002

Surplus N (1998, kg/ha)

100

150

200

250

300

350

400

clay peat sand

Acceptable:

250 ? peat

130 light sand

Surplus N (1998, kg/ha)

100

150

200

250

300

350

400

clay peat sand

Acceptable:

250 ? peat

130 light sand

Strong reduction of surpluses is

needed

How to reduce surpluses?

limit to livestock density: animal accounting

or Limit to surpluses: mineral accounting

Limit to livestock density

N surplus

manure-N/ha170 kg

Reducing livestock density190 kg

288 kg

Limit to livestock density

N surplus

manure-N/ha170 kg

190 kg

Limit to livestock density

N surplus

manure-N/ha170 kg

190 kg

Not all farms below acceptable level

Limit to the surplus of N

N surplus

manure-N/ha170 kg

Improving management

288 kg

190 kg

Limit to the surplus of N

N surplus

manure-N/ha170 kg 288 kg

190 kg

Limit to the surplus of N

N surplus

manure-N/ha170 kg 288 kg

All farms below acceptable level

190 kg

Mineral accounting, with limited surpluses

Advantages:- environmental quality is better guaranteed- more attractive if land is expensive and animal

density is high

Disadvantages:- High cost to control- Acceptance of EU?

How to reduce surpluses?

Improve N-turnover in farm components: less inputs needed

herd

manurecrop

soil

feedMilk/meat

fertilizer

80%53%

18%

71%

1987 200?

De MarkeDe MarkeAn experimental farm on light sandy soil, with an average intensity of milk production and very tight environmental standards

How to reduce surpluses?

herd

manurecrop

soil

feedMilk/meat

fertilizer

80%

53%

18%

71%

23%

92%70%

93%

Improved N-turnover De Marke

Results 1993-1998

Mineral fertiliser-N : 70 kg/ha reduction of 70 %

Purchased feed: 2,000 kg dm/ha Reduction of 60 %

Surplus N: 150 kg/ha

Results 2004

Mineral fertiliser-N : 0 kg/ha reduction of 100 %

Purchased feed: 2,000 kg dm/ha Reduction of 60 %

Surplus N: 100 kg/ha

How to convince farmers?

Father G. van den Elsen (founder of Rabo-bank, Campina etc.): “It is impossible to convince farmers only with books and journals. The truth should be pumped into their heads by clear, visible examples”. (Sociologie der Boeren, 1918)

1999 2005

Cows Cows && Opportunities Opportunitiescommercial intensive dairy farms, demonstrating possibilities to

realise low surpluses

Characteristics of pilot farms

1998 2003 Difference

Quota (kg milk) 554,500 703,000 +148,500 Farm area (ha) 41 50 +9 Quota per ha 14.300 15.000 +700 Cows 69 80 +11 Milk per cow (kg/jr) 8,000 8,700 +700

Environmental performance pilot farms

1998 2002 Difference

input N: - mineral fertilisers 180 85 -95 - purchased feed 160 150 -10 surplus N 266 181 -85 input P: - mineral fertilisers 13 4 -9 - purchased feed 25 23 -2 surplus P 18 9 -9

Income N surplus

Measures to reduce surplus

Economics

Income N surplus

measures

Pilot farms

Economics

Income N surplus

measures

Economics

2,500

euro

Pilot farms

Dutch Mineral Accounting System (1998 –

2006)

Input

concentrateslivestockroughagemanure

artificial fertilizer

Output

milk, livestockroughagemanure

Farm gate surplus

Farm gate balance

Dutch Mineral Accounting System (1998 –

2006)

Input

concentrateslivestockroughagemanure

artificial fertilizer

Output

milk, livestockroughagemanure

Farm gate surplus

Farm gate balance

About 70 kg N below real surplus (including deposition, clover etc.)

Permitted farm gate surpluses (kg

N/ha)1998 2005

Grassland* 330 180

Arable land* 175 100

* On light sandy soils 40 kg less

Real N-surplus of very specialized dairy

farms (kg/ha)1998 2002

clay 339 209

peat 344 238

sand 375 197

average 355 205

Average annual decrease: 38 kg = 11%

(-150)

Farmgate N-surplus of all dairy farms

0

50

100

150

200

250

300

350

400

450

1986 1988 1990 1992 1994 1996 1998 2000

year

N s

urp

lus

(kg h

a-1)

sand clay sand, leaching-sensitive peat

MINAS

Save area

P2O5 -surplus of very specialized dairy farms

(kg/ha) 1998 2002

clay 52 33

peat 62 40

sand 67 23

average 60 29

Average annual decrease: 8 kg = 13%

(-31)

The future

We love mineral accounting, but European Court of Justice does not

The future

We love mineral accounting, but European Court of Justice does not

We will introduce application standards for fertilizers in 2006

The future

We love mineral accounting, but European Court of Justice does not

We will introduce application standards for fertilizers in 2006

We expect that costs will increase for farmers , but costs for government will be lower

The future

We love mineral accounting, but European Court of Justice does not

We will introduce application standards for fertilizers in 2006

We expect that costs will increase for farmers , but costs for government will be lower

We hope that in the future a mineral accounting system can be reintroduced, because nutrient surplus is the better indicator for environmental quality

Thanks!