Post on 30-Dec-2015
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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80
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