Estimation of N-surplus and -losses in Denmark using ’Farm-N’

Ministry of Food, Agriculture and Fisheries

Danish Institute of Agricultural Sciences

Estimation of N-surplus and -losses in Denmark using ’Farm-N’

Dept. for Agroecology, Danish Institute of Agricultural Sciences

www.Farm-N.dk

Ib Sillebak Kristensen



Motivation

• Legislation on the losses of N to the environment – nitrates (EU Nitrates Directive)

– ammonia (EU National Emissions Ceilings Directive)

– nitrous oxide (Kyoto agreement)

• Farm N surplus is good environmental indicator

• Farm N surpluses can be calculated fairly accurately and reliably



Herd Animals

Milk

Manure

Manure

Manurestorage

Manure from storage

Cash crops

Manure fromgrazing

Input-output = Farm gate surplus

N2-fixation

Fertilizer

Field

Concentrate

GrazingSilage, grain& straw (net)

Nitrogen flow on farm

Fields

Cattle / Pigs

Inputs Outputs

Losses

Farm

N-flows, [kg N/ha] +/- standard deviation

Farm Dairy LSU/ha= 1,9Inputs Outputs

Herd , 190 LSU 48 +/- 1 MilkFeed 105 +/- 4 N-surplusHerd = 204 +/- 5

N-effHerd = 61 / 260 = 23% 13 +/- 1 MeatBedding 4 +/- 1

Total 155 +/- 29N-lossManure 24

179 +/- 28

Field = 100 HaN-surplusField = 143 +/- 41

Fertilizer 72 +/- 4 N-effField = 155 / 299 = 52% 0 +/- 0 Crops

Fixation 32 +/- 8

Deposition 16 +/- 5

Total inputs 228 +/- 11 N-surplusFarm gate = 168 +/- 11 Total outputs 61 +/- 2

N-effFarm gate = 61 / 228 = 27%


Farm Dairy LSU/ha= 1,9Inputs Outputs



Total 155 +/- 29N-lossManure 24

179 +/- 28

Field = 100 HaN-surplusField = 143 +/- 41


Fixation 32 +/- 8

Deposition 16 +/- 5


N-effFarm gate = 61 / 228 = 27%

Reliable



The tool

• A whole-farm model for N flow

• Focus on the interaction between crop and livestock production

• Static model, results represent average situation

• Deterministic, so the same input produces the same output

• Underlying assumption: Nutrient quota used to regulate management.

• Desired feature: Best possible management

• As simple as possible



Farm Field Rotation Cattle Pig Manure Balance Results Doc

Farm-N

http://130.226.173.223/farmn/



Field

Rotation 1Arable rotation with grass/clover ley

Rotation 2Continuous maize

Farm-N

http://130.226.173.223/farmn/



Crop rotation

Optimized crop rotation

with respect to- maximum yield- minimum N-surplus

subject to- repeating crop sequence- same crop acreage each year- ad hoc rules

Farm-N

http://130.226.173.223/farmn/



Cattle

BreedCategoriesNumbersFeeding regimeProduction levelEfficiencyHousing type

Farm-N

http://130.226.173.223/farmn/



Pigs

CategoriesNumbersFeeding regimeProduction levelEfficiencyHousing type

Farm-N

http://130.226.173.223/farmn/



Manure

Optimized manure application

with respect to- maximum utilization

subject to- fields allowed to receive manure- crop-specific utilization rates

Farm-N

http://130.226.173.223/farmn/



Balance of field – livestock interactions

Produced - used - losses + bought – sold = 0

System definitions

Technical coefficients

Rest

Farm-N

http://130.226.173.223/farmn/



Results

Farm-N

http://130.226.173.223/farmn/



Results

Distribution of Farm gate N-surplus = 168 kg N/ha

Lost of input7%4%1%7%2%3%5%

Farm-N

http://130.226.173.223/farmn/

N-balances on idealized DK dairy farm, 1.9 LSU/ha irrigated sand.

DK dairy

Grass/clover

Maize

Area use, % low N-eff high N-eff

-grass/clover 30% 70% 30%

-maize 20% 0% 35%

N-import, N ha-1

-feed 109 91 79

-mineral N 72 100 80

-fixation + dep. 48 89 47

N-export, N ha-1 -61 -61 -61

Farm N-balance 168 220 145

N-losses on idealized DK dairy farms, irr. sand. kg N ha-1

DK dairy

Grass/ Clover

Low N-eff

Maize

High N-eff

Farm N-balance 168 220

145

N-losses

-amm. vol. 31 34 28

-denitrification 17 23 18

-acc. soil-N 49 84 53

-leaching 71 79 47

N-losses on idealized DK dairy farms, irr. sand, kg N ha-1

DK dairy

Grass/ clover

low N-eff

Maize

high N-eff

Farm N-balance 168 220 145

N-losses

-amm. vol. 31 34 28

-denitrification 17 23 18

-acc. soil-N (low C/N) 49 (38) 84 (73) 53 (41)

-leaching(low C/N) 71 (82) 79 (89) 47 (57)



Conclusions

• A web-based prototype is available• Uses data available to the farmer• Negotiations with Danish authorities on its

use for screening environmental impacts



Future developments

• Farm P balance ?• Data import from farm management programs

?• Online collaboration on system definitions

(farmer, adviser, regulation authority) ?• Internationalisation ?



www.farm-N.dk/FarmNTool

Herd Animals

Milk

Manure

Manure

Manurestorage

Manure from storage

Cash crops

Manure fromgrazing

Input-output = Farm gate surplus

N2-fixation

Fertilizer

Field

Rouhage+ grain for fodder

Straw

Storage:-rouhage-grain-straw

Concentrate

GrazingSilage, grain& straw (net)


Farm Dairy LSU/ha= 1,9Inputs High C/N Outputs



Total 155 +/- 29Grazed 45 +/- 13 N-lossManure 24Conserved 85 +/- 25Grain 26 +/- 2 0 +/- 0 Manure

179 +/- 28

Manure 0 +/- 0 Field = 100 Ha 0 +/- 0 GrainN-surplusField = 143 +/- 41


Fixation 32 +/- 8

Deposition 16 +/- 5


N-effFarm gate = 61 / 228 = 27%


Farm Max grass/clover LSU/ha= 1,9Inputs Outputs



Total = 205 +/- 42Grazed = 89 +/- 26 N-lossManure 21

Conserved = 111 +/- 33Grain = 6 +/- 1 0 +/- 0 Manure

186 +/- 29



Fixation 73 +/- 18

Deposition 16 +/- 5


N-effFarm gate = 61 / 251 = 24%


Farm Max. maize & W/C LSU/ha= 1,9Inputs Outputs



Total 165 +/- 40Grazed 25 +/- 7 N-lossManure 25Conserved 133 +/- 39Grain 8 +/- 1 0 +/- 0 Manure

182 +/- 29



Fixation 31 +/- 8

Deposition 16 +/- 5


N-effFarm gate = 61 / 230 = 26%


Farm Arable, irrigated LSU/ha= 0,5Inputs Outputs



0 +/- 0N-lossManure 9

0 +/- 0 Manure

46,3 +/- 7

Manure 0 +/- 0 Field = 100 Ha 90,6 +/- 9 GrainN-surplusField = 92 +/- 14


Fixation 2 +/- 0

Deposition 16 +/- 5


N-effFarm gate = 121 / 223 = 55%


Farm Pig, sand LSU/ha= 1,4Inputs Outputs



0 +/- 0N-lossManure 25

0 +/- 0 Manure

130 +/- 21

Manure 0 +/- 0 Field = 100 Ha 90,8 +/- 9 GrainN-surplusField = 110 +/- 23


Fixation 2 +/- 0

Deposition 16 +/- 5


N-effFarm gate = 180 / 315 = 57%



http://www.Farm-N.DK/

Litteraturliste

Berntsen, J. and Petersen, B. M. 2005: C-TOOL, Danish version see http://web.agrsci.dk/jbe/bin/ctool.html. Jørgensen, M. S., Detlefsen, N., and Hutchings, N. J. 2005: FarmN: A Decision Support Tool for Managing Nitrogen Flow at the Farm Level. EFITA (European Federation for Information Technology in Agriculture, Food and the Environment) konferencen, Vila Real, Portugal, 25.-27. juli-2005. http://130.226.173.223/farmn/FarmNTool.pdf 1-7. Kristensen, I. S. 2005a: Nitrogen balance from cash crop farms (2002). http://www.lcafood.dk/processes/agriculture/N_balance_cash_crop_farms_2002.htm. Kristensen, I. S. 2005b: Nitrogen balance from dairy farms (2002). http://www.lcafood.dk/processes/agriculture/N_balance_dairyfarms_2002.htm#table_1. Kristensen, I. S. 2005c: Nitrogen balance from pig farms (2002). http://www.lcafood.dk/processes/agriculture/N_balance_pigfarms_2002.htm. Kristensen, I. S. 2005d: Uncertanties on Farm Gate N-balances, see. http://www.agrsci.org/afdelinger/forskningsafdelinger/jpm/medarbejdere/isk/oversigtsside_med_publikationer. Kristensen, I. S., Detlefsen, N., Hutchings, N., and Petersen, B. M. 2005: Documentation of the used coefficients in Farm-N. http://130.226.173.223/farmn/Documentation%20of%20the%20used%20coefficients%20in%20Farm.pdf. Petersen, B. M. and Berntsen, J. 2003: The turnover of soil organic matter on different farm types. http://www.darcof.dk/enews/sep03/orgmat.html. DARCOF.eNews. September 2003.

Estimation of N-surplus and -losses in Denmark using ’Farm-N’

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