N-flow in Danish agriculture And FarmAC in Amazonas

Transcription

1 N-flow in Danish agriculture And FarmAC in Amazonas Ib Sillebak Kristensen & Nick Hutchings Aarhus University Dept. of Agroecology Foulum. Denmark 10. Feb Campinas, Brazil.

2 part 1 Principles for Nutrient flows, examplified on average DK agriculture

3 Farm N balance & N-leaching Nitrate (mg/l) N-surplus (kg/ha) Groundwater recharge year (CFC-year) Nitrate in oxic groundwater (nitrate>1mg/l, iron<0.2 mg/l & oxygen>1mg/l) Moving average of nitrate in groundwater Upward nitrate trend Downward nitrate trend N surplus in agriculture Hansen et al. Env Sci. Tech. (2011)

4 N-eff. in Danish Agriculture

5 Danish Farm N surplus Development and Variation N- surplus (kg N/ha/yr) Nsurp2008 Nsurp2002 Nsurp1996 Nsurp1990 Expon. (Nsurp2008) Expon. (Nsurp2002) Expon. (Nsurp1996) Expon. (Nsurp1990) Livestock density (kg Manure- N/ha/yr.) Dalgaard et al. BiogeoSciences 9 (2012)

6 N-flow on 4 organic dairy farms in Estonia in 1998 Herd 30 N/cow in milk & animals 75N/cow in manure from stable 20 hkg DM grass/ha Fodder 13 hkg grain/ha Manure 35 N/cow (47 %) in manure amm. los Grass Field 21 hkg grain/ha 40 N/cow in manure from compost

7 Farm Herd Manure from grazing Milk & animals Feed Manure from stable Fodder & straw Feeding loss Straw Manure Manure Fixation Precipitation Fertilizer Seed Field Cash crops Surplus

8 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 = 112

9 N-flows, [kg N/ha] +/- standard diviation Farm Dairy cattle, demo LSU/ha 1,9 Inputs Outputs Concentrated feed 95 +/- 4 Herd = 190 DE N-surplus Herd = 211 +/- 42 = 20% SD 61 +/- 2 Milk N-eff Herd = 61 / 272 = 22% N-effHerd Feed 177 +/- 30 N-loss manure /- 30 Artificial fertilizer 58 +/- 3 Field/Soil balance on 100 ha Fixation 31 +/- 8 N-surplus Field = 116 +/- 43 = 37% SD Nedbør m.v. 16 +/- 5 N-eff Field = 177 / 293 = 60% N-effField Total inputs 200 +/- 10 N-surplus Farm gate = 139 +/- 11 = 8% SD Total outputs 61 +/- 2 Farm-N tabel.xls N-eff Farm gate = 61 / 200 = 31% N-effFarm gate D:\ibdata\tekst\Fasset\Farm_N\Internet\FarmN\Farm-N tabel.xlssheet= TestFig Field-balance: Un-secure Farm-balance: Reliable 9

10 Farm Herd Manure from grazing Milk & animals Feed Manure from stable Amm. loss stable Manure Straw Fodder & straw Feeding loss Straw Manure Amm. loss manure storage Manure Fixation Precipitation Field Amm. loss spreading Fertilizer Denitrification Seed Cash crops Surplus = leaching and soil N changes

11 N-losses in DK-agriculture, 1999 Kg N ha -1 year -1 Farm gate N-surplus 125 Amm. los in: % N-los of input - Stall -9 9 % - Storage -4 4 % Field N-surplus 112 Amm. los: - Spreading % - Grazing -1 7 % - Fertiliser -5 3 % - Crops -4 4 % Denitrifikation % Change in soil-n 0 N-leaching (=difference) - 78

12 N/ha Farmgate N balancer on arable sandy soil 200 Dairy conv. 150 Pig conv. 100 Dairy organic 50 Arable organic 0 Arable conv. LU/ha 0,00 0,50 1,00 1,50 2,00

13 Danish emission coefficients for ariel losses from animal manure. Year Ammonia loss DenitrificationAmmonia loss Denitrification Total in stall in stall in storage in storage % of ab dyr % of ab stall % of Slurry Deep Slurry Deep Slurry Deep Slurry Deep ab dyr Animals Stall litter litter litter litter Creatures Solide floor Part slatted Deep litter Pigs Part slatted for slaughter Full slatted Feather Deep litter Fer animals Ditch S ee Poulsen et al. (1998) and Hutching s et al. (2001). F rom file=c HR - 99_06.xlsx

14 Farm Herd Manure from grazing Milk & animals Feed Manure from stable Manure Fodder & straw Manure Amm. loss Manure Fixation Precipitation Field Amm.loss Fertilizer Seed Organic soil-n Change in soil-n N Denitrifikation Cash crops Leaching

15 FarmAC model the basics

16 FarmAC model Focusses on livestock farming systems Ø 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 Ø Consistency between GHG and N emissions Ø Capture knock-on effects

17 Deposition Fixation Fertiliser Manure NO NO 3 NH NH 3,N 3, N 2 0,N 2 O 2 NH 3, N O Storage losses Exported NH 3, N 2 O NH NH 3,N 3, N 2 0,N 2 O 2 Exported NH 3, N 2 O Runoff NO 3 Exported NH 3, N 2 O NH NH 3,N 3, N 2 0,N 2 O 2 17

18 Fertiliser Manure CO NO 2 3 NH 3, N O Storage losses Exported NH 3, N 2 O CH NH 4,CO 3, N 2 O Exported NH 3, N 2 O Runoff NO 3 Exported NH 3, N 2 O CH NH 4,CO 3, N 2 O 18 CH NH 4,CO 3, N 2 O

19 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

20 How the model sees grain crops 1 st product (e.g. grain) 2 nd product (e.g. straw) (may or not be harvested) above-ground crop residue root + leaf scenescence

21 How the model sees forage crops Grazed forage Grazed forage Unutilised forage Ungrazable residue root + leaf scenescence Ungrazable residue root + leaf scenescence

22 Grazed yield Modelled yield Grazed yield Modelled yield Unutilised (residue) Ungrazable residue Ungrazable residue Enough production More than enough production

23 Deficit! Modelled yield Grazed yield What the cattle thinks they can eat What the pasture can supply Ungrazable residue Not enough production

24 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

25 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

26 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

27 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

28 Calculating mineral N available N outputs Ammonia emission, which varies between fertiliser, manure, urine application method N 2 O and N 2 emission N 2 O via emission factor (varies between sources) N 2 = N 2 O * factor N leaching, which varies with timing of application of fertiliser/manure Period with drainage

29 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

30 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

31 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

32 Total soil-c Forest Slow degradable ½ time life = 365 years degradeble ½ time life =5 year Quick degradeble ½ time life =1,5 mdr

33 Bare soil

34 Grass no cattle

35 Grass few cattle

36 Grass more cattle

37 N inputs light grazing

38 N outputs light grazing

39 C stored in soil long term

40 Dry matter production long term

41 N inputs long term

42 N outputs long term

43

44 Losses are calculated for the whole crop period

45 So it might be sensible to divide the crop in two

46 Soil-C in farm type DK dairy C (t/ha) Pig Arable År

47 Soil pools never in equilibrium