Justus-Liebig-University Giessen Institute of Landscape Ecoology and Resources Management Martin Bach Assessment of agricultural nitrogen balances for

Justus-Liebig-University Giessen Institute of Landscape Ecoology

and Resources Management

Martin Bach

Assessment of agricultural nitrogen balances for

municipalities – Example Baden-Wuerttemberg

[email protected]

EEA Agri-water Expert meeting, Copenhagen, 21-22 Feb 2005

Institute of Landscape Ecology and Resources Management

EU, OECD: Agri-sustainability indicator - environmental pressures (water, atmosphere) - waste of resources

Effectiveness of policies: EU Nitrate Directive, national action programmes

Verification of supra-national treaties, e.g. OSPARCOM

Sustainability Strategy Program of the German Gouvernment: DUX-Indicator (‚German Environment Index‘) „Trend of the national nitrogen surplus“

Component of „National Gross Environmental Budget“ (UGR, Umwelt- ökonomische Gesamtrechnung), indicating the external costs of nitrogen losses into air, terrestrial ecosystems, surface waters, groundwater, sea

WFD implementation: source appointment, prediction of efficiency of reduction measures

Farm level: Optimization of N-management (tools e.g.: EMA in the UK; REPRO, QSL in Germany)

Usage of ‚nitrogen balance surplus‘


„Best available indicator“ for water quality eutrophication by non-point source N losses

e.g. Modelling approaches of EUROHARP models,especially MONERIS

WFD: ‚10 km² basin units‘

spatially differentiated calculation of N surplus

max resolution of ag-census based N balance

Germany: municipalities (EU LAU level 2)

Nitrogen soil surface surplus in the WFD context


Problems

Lack of data (data secrecy)

Estimation of N mineral fertilizing quantities

Ag-census based calculationof nitrogen soil surface surplus


Missing data of the Agricultural Census

Background

Data secrecy policy: a statistical data won‘t be published when based on three or less individual values

Replacement

by estimated figures: missing data recalculted as thedifference between „sum over a county“ and „sum over all muncipalities with published data“


Missing data of the Agricultural Census- Crop acreage

Crop (acreage) No. of missing data

Fraction of municipalities*

Missing quantity% of state total

Agricultural land total 9 0,8 % 0,1 %

Arable land 31 1,4 % 0,1 %

Pasture 16 26,6 % 0,1 %

Orchards 295 n.d. 2,3 %

Vineyards n.d. 0,1 % 2,9 %

Wheat 53 4,8 % 0,1 %

Barley 117 10,5 % 0,7 %

Legumes 326 29,3 % 12,6 %

Potatoes 139 12,5 % 1,9 %

Sugar beet 143 12,9 % 4,0 %

Fodder maise 163 14,7 % 1,7%

Oilseed rape 232 20,9 % 2,8 %

Vegetable 340 30,6 % 12,1 %

*) n = 1112 municipalities


Livestock (heads) No. of missing data

Fraction of municipalities*

Missing quantity % of state total

Bovines total 113 10,2 % 0,6 %

- therefore cows 172 15,5 % 1,4 %

Pigs total 235 21,2 % 2,4 %

- therefore souws 339 30,5 % 7,6 %

Sheep 442 39,8 % 32,1 %

Poltry 284 25,6 % 42,1 %

*) n = 1112 municipalities

Missing data of the Agricultural Census- Livestock


„farmer‘s N fertilization scheme“:

N plant demand = N mineral fertilization + N organic fertilizer*efficiency factor + other N supply

N plant demand: crop specific N demand for optimal harvest yield (table values)

N organic fertilizing: N supply to the field with farm produced manure; N supply = N excretion of livestock minus volatilzation losses

Efficiency factor: fraction of N in manure which is availabe for the field crop, according to farmers fertilization calculation

Other N supply: N-fixation by legumes, secondary organic fertilizers

Estimation approch of nitrogen mineral fertilization

N mineral fertilization = N plant demand – N organic fertilizer*efficiency factor – other N supply


Estimation approach of nitrogen mineral fertilization

„Validation“ of the assessment:

Estimated N mineral fertilizer amounts summed up over all crops and all counties in Germany mineral fertilizer consumption of agriculture in total (census based)

Best calibration with an efficiency factor = 36 % (average Germany 1998/2000).

Figures (kg N/ha AA, average Germany 1998/2000):

plant demand – organic fertilizer*efficiency factor – other supply = mineral fertilizer

144 – 53 * 0,36 – 15 = 110

used for calculation of mineral fertilizing of individual municipalities

Farmers do not accounted for 64 % of N in their manure (= potential losses when planning crop fertilization schemes)


31 - 49

50 - 69

70 - 89

90 - 109

110 - 129

130 - 177

Gemeindefr. Geb.

k. Angabe (LF=0)

Bodensee

Überschuss Flächenbilanz kg N/ha LF

Nitrogen soil surface surplus kg N/ha AA

no agriculture

no data

Lake Contance

Nitrogen surplus

Results forMunicipalities* Baden-Wuerttemberg 1999

*) EU LAU level 2, NUTS 5


Quality check of nitrogen soil surface surplus results

Nit

rog

en s

urp

lus

bas

ed o

n

Ag

ricu

ltu

ral

Cen

sus

(kg

N/h

a A

A)

40 80 120 160 20040

80

120

160

200

1 : 1-Line

r² = 0,45

Nitrogen surplus acc. to empirical data (kg N/ha AA)

Comparison of Ag-Census based vs. empirical N budgets (mainly farm based data)

Database: Literature review, 8 studies with together 32 municipalities (in 5 German states)(Bach et al.,1996)


<= 40 % 41 - 60 % 61 - 80 % 81 - 125 %126 - 150 % > 150 %

Baden-Wuerttemberg: NO3-conc. in aquifers measured vs. modelled

Source: J. Ruf, Environment Agency Baden-Wuerttemberg, 2004

Groundwater NO3-concentration

Relationmeasurement / model (%)


Assessment of nitrogen balances for municipalities yields reasonable, quantitative figures with high spatially resolution

Results are an operational tool for the WFD status reports (‚at risk‘ vs. ‘not at risk‘; source apportionment)

But:

Farm-gate balances are methodologically more precise and the results indicate the problem closer to its origin (farms with huge livestock density)

Outlook: Prediction of effectiveness (and efficiency) of nitrogen loss reduction measures in ag production systems needs process- oriented nitrogen models (e.g. SWAT, DNDC and others) - ‚nitrogen surplus‘ is not sufficient for this purpose.

Resume



Thank you for your attention!

You are a great audience!


• Groundwater • Tile drainage • Erosion • Surface runoff • WWTP • Urbans areas • Atmospheric deposition

Source: Landesanstalt fuer Umwelt-schutz Baden-Württemberg, 2000

Total Nitrogen emissions from:

MONERIS (Behrendt et al., 1999)

Results Baden-Wuerttemberg


Balance PositionNational

(farm-gate) balance

Soil surface (crop production)

balancekg N/hectare AA

Mineral (chemical) fertilizier +109 +109

Secondary organic fertilizer (sewage sludge, compost) + 4 + 4

Imported fodder + 22

Fodder from domestic processing + 14

Organic fertilizing (manure) + 50

Atmospheric deposition (netto) NH3-deposition on ag area

+ 10 + 10+ 12

Legume nitrogen fixation + 11 + 11

Market export of crop products - 35

Market export of livestock products - 19

Harvest withdrawal -121

Balance surplus = 117 = 75

Nitrogen balance of German agriculture 2000


Wasserschutz-gebietszonen

WSG-ZonenZone IZone IIZone IIIZone IIIAZone IIIB

Landnutzung

N-Saldo

Hydrogeolog.Einheiten

Boden (NAG),Niederschlag

Bsp. Hessen: Auswertung WSG


Schätzung NO3-Konz. in GW-Messstellen Regressionsansatz

log (CNO3) = a0 + a1*Wald% + a2*Siedl% + a3*Grünl%

+ a4*(Acker%*N-Saldo) + a5*Tiefe + a6*SWS

CNO3 = Mittlere Nitratkonz. des Rohwassers (mg NO3/l)

Wald% = Anteil des Waldes an der Gesamtfläche (%)

Grünl% = Anteil des Grünlands an der Gesamtfläche (%) Siedl% = Anteil der Siedlung an der Gesamtfläche (%) Acker%*N-Saldo = Produkt aus Ackerlandanteil und mittlerem

N-Bilanzüberschuss

Tiefe = Mittlere Rohwasserentnahmetiefe (m)

SWS = Geschätzte mittlere Sickerwasserspende (mm/a)


Bsp. Hessen: Regressionsgleichung - Brunnen

Modellschritt r2 Korrigiertes r2

1. Wald% ,259 ,258

2. Grünl% ,341 ,339

3. Tiefe ,397 ,395

4. SWS ,418 ,415

Alle Brunnen-Messstellen (Hessen gesamt), n = 811

log (CNO3) = 1,964 – 7,04E-03*Wald% – 4,15E-03*Grünl%

– 2,43E-03*Tiefe – 6,19E-04*SWS

NO3-Konz. (mg/l) (berechnet)

NO

3-K

on

z . (

mg

/l ) (

ge m

esse

n)

0

25

50

75

100

0 25 50 75 100


Einheit: Nordhessisches Buntsandsteingebiet , n = 82

log (CNO3) = 1,889 – 8,57E-03*Wald% – 5,97E-04*SWS

SQS r2 Korrigiertes r2

Wald% ,697 ,694

SWS ,716 ,709

NO3-Konz. (mg/l) (berechnet)

NO

3-K

on

z . (

mg

/l ) (

ge m

esse

n)

0

25

50

75

100

0 25 50 75 100

Bsp. Hessen: Regressionsgleichung - Quellen (‚SQS‘)


Hydrogeologische

GroßeinheitenBrunnen Quellen (SQS)

n r2 n r2

Hessen gesamt 811 ,415 1057 ,406

Nordhessisches Buntsandsteingebiet 91 ,569 82 ,709

Niederh. Senke und Röt-Muschelkalk 25 ,607 43 ,469

Rheinisches Schiefergebirge 211 ,329 276 ,474

Basaltgebiete 138 ,358 83 ,367

Osthessisches Buntsandstein-Gebiet 192 ,424 228 ,552

Quartär und Tertiär des Untermain 49 ,327 7 n.s.

Kristallin und Rotliegendes 71 ,274 238 ,280

Quartär des Oberrheingrabens 12 n.s. 20 n.s.

Buntsandstein-Gebiet des Odenwaldes 22 ,560 80 ,423

Bsp. Hessen: Ergebnisse (r²)


0%10%20%30%40%50%60%70%80%90%

100%

0,0 10,0 20,0 30,0 40,0 50,0 60,0

c(NO3) im Sickerwasser (berechnet)

Den

itrifi

katio

ns-

Rat

e

Bsp. Baden-Württemberg:Berechnete Denitrifikationsraten

Quelle: J. Ruf, LfU Baden-Württemberg, 2003

Modellberechnung*

Messung Grundwasserleiter

Kluftgrundwasser Karst Sonstige

*) Denitrifikationsrate = f{N-Überschuss LF, N-Deposition Wald, Nutzungsanteile, Sickerwassermenge, c(NO3)-GW gemess. }


1950 1960 1970 1980 1990 20000

50

100

150

0

50

100

150

National balance („farm gate“) Soil surface balance

Nit

rog

en

su

rplu

s (

kg

N/h

a A

A)

Nitrogen balance surplus Germany 1950 to 2002*

*) 2002: preliminary results


Nitrogen Surplus- Soil surface balance -

of the AgriculturalArea (AA) 1999

- Germany, NUTS 3 level (counties) -

21 - 50

51 - 80

81 - 110

111 - 150

151 - 200

201 - 260

kg N / hectare AA


Nitrogen Surplusrelated to the total land area of

the counties (all land uses*) 1999

- Germany, NUTS 3 level (counties) -

*) AA: N soil surface surplus of the agricultural land; other uses (forest; urban and traffic areas): 5 kg N/ha N surplus

kg N / hectare total area

5 - 20

21 - 50

51 - 80

81 - 110

111 - 150

151 - 200

201 - 210


Überschuss Stickstoff-Flächenbilanz

N-Bilanzüberschuss Baden-Württemberg MONERIS Ergebnisse (Behrendt et al.)

Quelle: Landesanstalt für Umwelt-schutz Baden-Württemberg, 2000

<= 70 kg kg N/ha

71 – 80 kg N/ha

81 – 90 kg N/ha

91 – 100 kg N/ha

101 – 110 kg N/ha

111 – 120 kg N/ha

121 – 130 kg N/ha

>130 kg N/ha


Stickstoff-FlächenbilanzüberschussLandwirtschaft (Bach / 1995)

Stickstoff-HoftorbilanzüberschussLandwirtschaft (Zeddies / 2001)

Nährstoffbilanzierung Baden-Württemberg- MONERIS Baden-Württemberg -

Quelle: LfU – Landesanstalt für Umweltschutz Baden-Württemberg – Sachgeb. 41.1


Nährstoffbilanzierung Baden-Württemberg- MONERIS Baden-Württemberg -

Quelle: LfU – Landesanstalt für Umweltschutz Baden-Württemberg– Sachgeb. 41.1

Gesamte spezifische Stickstoff-Emissionen nach MONERIS:

• Grundwasser • Drainagen • Erosion • Abschwemmung • Kläranlagen • Urbane Flächen • Atmosphär. Deposition


Überschuss derStickstoff-

Flächenbilanz der Gemeinden in Hessen 1999

Bach und Frede (2002)

kg N / ha LF

20 - 40 41 - 60 61 - 80 81 - 100101 - 115115 - 130


EU, OECD: Agri-sustainability indicator - environmental pressures (water, atmosphere) - waste of resources

Effectiveness of policies: EU Nitrate Directive, national action programmes

Verification of supra-national treaties, e.g. OSPARCOM

Sustainability Strategy Program of the German Gouvernment: DUX-Indicator (‚German Environment Index‘) „Trend of the national nitrogen surplus“

Component of „National Gross Environmental Budget“ (UGR, Umwelt- ökonomische Gesamtrechnung), indicating the external costs of nitrogen losses into air, terrestrial ecosystems, surface waters, groundwater, sea

WFD implementation: source appointment, prediction of efficiency of reduction measures

Farm level: Optimization of N-management (tools e.g.: EMA in the UK; REPRO, QSL in Germany)

Usage of ‚nitrogen balance surplus‘

Documents

Justus-Liebig-University Giessen Institute of Landscape Ecoology and Resources Management Martin Bach Assessment of agricultural nitrogen balances for