N-flow in Danish agricultureAnd FarmAC in Amazonas

Ib Sillebak Kristensen & Nick Hutchings

Aarhus University

Dept. of Agroecology

Foulum. Denmark

10. Feb. 2015. Campinas, Brazil.

part 1

Principles for Nutrient flows, examplified on average

DK agriculture

Farm N balance & N-leaching

Hansen et al. Env Sci. Tech. (2011)

N-eff. in Danish Agriculture

Danish Farm N surplusDevelopment and Variation

0

50

100

150

200

250

300

350

400

450

0 50 100 150 200 250 300

N-s

urpl

us (k

g N

/ha/

yr)

Livestock density (kg Manure-N/ha/yr.)

Nsurp2008

Nsurp2002

Nsurp1996

Nsurp1990

Expon. (Nsurp2008)

Expon. (Nsurp2002)

Expon. (Nsurp1996)

Expon. (Nsurp1990)

Dalgaard et al. BiogeoSciences 9 (2012)

2008

1990

Herd

Manure

Field

30 N/cow in milk & animals

Fodder 35 N/cow (47 %) in manure amm. los

40 N/cow in manure from compost

13 hkg grain/ha

21 hkg grain/ha

20 hkg DM grass/ha

Grass

N-flow on 4 organic dairy farms in Estonia in 1998

75N/cow in manure from stable

Herd

Manure

Cash crops

Surplus

Field

Milk & animals

Fixation

Precipitation

Fertilizer

Seed

Fodder &straw

Feeding loss Straw

Manure from grazingFarm

Feed

Manure

Manure from stable

DK agriculture N-balance, 1999

Input Kg N ha-1 year-1

N-fertiliser 94

• Seed 2

• Fodder 79

• N-fixation 13

• Precipitation 16 

Output

• Milk -9

• Animals -28

• Cash crops -41 

los in .

-stall -storage = fieldbalance

N-surplus 125 - 9 -4 = 112

N-flows, [kg N/ha] +/- standard diviationFarm Dairy cattle, demo

LSU/ha 1,9Inputs Outputs

Concentrated feed 95 +/- 4 Herd = 190 DEN-surplusHerd = 211 +/- 42 = 20% SD 61 +/- 2 Milk

N-effHerd = 61 / 272 = 22% N-effHerd

Feed 177 +/- 30N-loss manure 23

188 +/- 30Artificial fertilizer 58 +/- 3 Field/Soil balance on 100 ha

Fixation 31 +/- 8 N-surplusField = 116 +/- 43 = 37% SD

Nedbør m.v. 16 +/- 5 N-effField = 177 / 293 = 60% N-effField

Total inputs 200 +/- 10 N-surplusFarm gate = 139 +/- 11 = 8% SD Total outputs61 +/- 2

N-effFarm gate = 61 / 200 = 31% N-effFarm gateFarm-N tabel.XLS D:\ibdata\tekst\Fasset\Farm_N\Internet\FarmN\Farm-N tabel.XLSSheet= TestFig

Farm-balance: Reliable

Field-balance: Un-secure

9

Herd

Manure Amm. loss manurestorage

Cash crops

Surplus = leaching and soil N changes

Field

Milk & animals

Straw

Manure

Fixation

Precipitation

Fertilizer

Seed

Fodder &straw

Feeding loss Straw

Manure from grazingFarm

Amm. loss stableFeed

Manure

Manure from stable

Amm. lossspreading

Denitrification

N-losses in DK-agriculture, 1999 Kg N ha-1 year-1 % N-los of

input

Farm gate N-surplus 125

Amm. los in:

- Stall -9 9 %

- Storage -4 4 %

Field N-surplus 112Amm. los:

- Spreading -8 11 %

- Grazing -1 7 %

- Fertiliser -5 3 %

- Crops -4 4 %

Denitrifikation -16 11 %

Change in soil-N 0

N-leaching (=difference) - 78

0

50

100

150

200

250

0,00 0,50 1,00 1,50 2,00

N/ha

LU/ha

-Farmgate N balancer on arable sandy soil

Arable conv.

Arable organic

Dairy organic

Dairy conv.

Pig conv.

Danish emission coefficients for ariel losses from animal manure. Year 2005.Ammonia loss DenitrificationAmmonia loss Denitrification Totalin stall in stall in storage in storage

% ofSlurry Deep Slurry Deep Slurry Deep Slurry Deep ab dyr

Animals Stall litter litter litter litterCreatures Solide floor 10 0 2 0 12

Part slatted 8 0 2 0 10Deep litter 6 0 14 5 23

Pigs Part slatted 8 0 3 0 10for slaughter Full slatted 16 0 3 0 18Feather Deep litter 20 0 8 10 34Fer animals Ditch 50 0 2 0 51See Poulsen et al. (1998) and Hutchings et al. (2001). From file=CHR-99_06.xlsx

% of ab dyr % of ab stall

Herd

Manure

Cash crops

Denitrifikation

Leaching

Field

Organic soil-N

Milk & animals

Manure

Fixation

Precipitation

Fertilizer

Seed

Fodder &straw

Manure from grazingFarm

Change in soil-N

Feed

Manure

N

Manure from stable

Amm.loss

Amm. loss

FarmAC model – the basics

FarmAC model Focusses on livestock farming systems

Can be used for arable agriculture Intended to have wide applicability Simple enough that demand for inputs and

parameters is manageable Complex enough to describe consequences of

mitigation/adaptation measures Mass flow for C and N

Consistency between GHG and N emissions Capture knock-on effects

17

DepositionFixationFertiliserManure

NH3, N2OExported

NH3, N2ONH3,N20,N2

NH3, N2ONH3,N20,N2

NO3NO3

NH3, N2ONH3,N20,N2

NH3, N2OExported

NH3, N2OExported

NO3Runoff

NH3, N OStoragelosses

18

NO3Runoff

NH3, N2OExported

FertiliserManure

NO3CO2

NH3, N2OCH4,CO2

NH3, N2OCH4,CO2

NH3, N2OCH4,CO2

NH3, N2OExported

NH3, N2OExported

NH3, N OStoragelosses

Components• Cattle model (simplified Australian)

– energy and protein determine growth/milk

• Animal housing and manure storage (mainly IPCC)

• Crop model

– Potential growth * N limitation * water limitation

• Soil model

– simple soil water model

– simple soil C and N model

1st product (e.g. grain)

2nd product (e.g. straw)(may or not be harvested)

above-groundcrop residue

root + leafscenescence

How the model sees grain crops

Grazed forage

root + leafscenescence

Ungrazable residue

root + leafscenescence

Ungrazable residue

Unutilised forage

Grazed forage

How the model sees forage crops

Enough production More than enough production

Grazed yield

Unutilised (residue)

Ungrazableresidue

Modelledyield

Grazedyield

Ungrazableresidue

Modelledyield

Grazedyield

Ungrazableresidue

Modelledyield

Deficit!

Not enough production

What the pasturecan supply

What the cattlethinks they can eat

Running FarmAC (1)• Define crop sequences

– area, soil type, irrigation– crop sequence (crops and bare soil)

• Define yield potentials and grazed yields– also define fate of crop residues

• Define livestock numbers, feed rations, livestock housing and manure storage– calculates manure production– calculates livestock production

• Decide manure and fertiliser applications

Running FarmAC (2)• Simulate!

• What can go wrong

–grazed yield cannot be achieved

–total production of grazed forage does not equal total consumption of grazed forage

Yield modelling• Potential yield (water and N unlimited)

– for all crop products

– input by users

• Calculate water-limited yield (Water balance)

• Calculate N uptake at water-limited yield

– includes N in above and below-ground crop residues

• Calculate mineral N available

• Mineral N or maximum uptake determines yield

Calculating mineral N available • Mineral N = mineral N input - losses

• N inputs

–atmosphere

–N fixation

–fertiliser

–manure

–urine

–mineralised soil, manure organic N, dung and crop residue N

Calculating mineral N available • N outputs

– Ammonia emission, which varies between

• fertiliser, manure, urine

• application method

– N2O and N2 emission

• N2O via emission factor (varies between sources)

• N2 = N2O * factor

– N leaching, which varies with

• timing of application of fertiliser/manure

• Period with drainage

Growth• Potential crop N uptake = crop N

uptake with water-limited yield

• If mineral N available >= potential crop N uptake

–Modelled growth = water-limited growth

• Otherwise

–Modelled growth = mineral N available/potential crop N uptake

How to define a permanent crop• The fertilisation necessary to achieve a

given yield will change with time

–For grazed crops, the fertilisation will be determined by the year with the least mineralisation of soil N

–Means that excessive fertiliser will be applied in other years

• Break the permanent crop into several crops

Amazonian forest

• Simulated here by teak• Main features:

– no export of products

– deep roots, high rainfall 1000 mm drainage and high temperature

– high C:N ration in residues

– N input 10 kg/ha/yr from precipitation

Forest

Quick degradeble ½ time life =1,5 mdr

degradeble ½ time life =5 year

Slow degradable ½ time life = 365 years

Total soil-C

Bare soil

Grass – no cattle

Grass – few cattle

Grass – more cattle

N inputs – light grazing

N outputs – light grazing

C stored in soil – long term

Dry matter production – long term

N inputs long term

N outputs long term

Losses are calculated for the whole crop period

So it might be sensible to divide the crop in two

Soil-C in farm type

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90

100

110

120

130

2000 2020 2040 2060 2080 2100

År

C (

t/h

a)

DK dairy

Pig

Arable

Soil pools never in equilibrium