Model based evaluation of agro-environmental measures in the federal

state of Brandenburg/Germany concerning nitrogen pollution of ground

and surface water

K. Christian Kersebaum Bettina Matzdorf

Joachim Kiesel Annette Piorr

Jörg Steidl

Leibniz-Centre for Agricultural Landscape Research (ZALF) e. V.W

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Outline

o Introduction

o Meteorological characterisation of the study area

o Agro-environmental measures in the Federal state of Brandenburg

o Modelling diffuse nitrogen leaching from the root zone for different

agricultural management options

o Identification of vulnerability zones for water resources

o Evaluation of actual agro-environmental measures

o Conclusions

• Description of the STATUS QUO (water quality) and evaluation

• Definition of a target status

•Development and realization of measure programs and management plans

• Collecting data about the present status of ground water and surface water

Introduction: Requirements of the Water Framework Directive of the EU

Development of measure programs

Goal: Most efficient allocation of measures for the reduction of nutrient pollution of water

resources

3) Allocation of measures to enhance their effectiveness

• Weighting the emissions from agricultural land on the basis of the retention potential of soils and aquifers

• Allocation within the region according to a priority ranking

2) Development and evaluation of mitigation options

• Catalogue of potential measures• Side specific evaluation regarding the targets and the

consequences for productivity (-> socio-economic effects)

1) Status quo analysis on land use related emissions

• Identification of land use induced problematic areas• Estimation of activity requirements

Climatic zoning regarding average air temperature (1961-1990)

Climatic zoning regarding average precipitation (1961-1990)

Climatic zoning regarding average potential evapotranspiration (1961-1990)

Spatial distribution of agro-environmental measures in Brandenburg Germany (status 2000/2001)

on arable land on grassland

B3-G organic grassland A5 special nature conservationA7 extensive fruit areasA3 restricted grassland A2 extensive grassland riversides A1 extensive grassland

B1 controlled integrated horticultureB5 conversion arable land to pasture

B3-G organic legume production

B3-D organic farming permanent crops

B3-A organic arable farming B4 soil conservation measures

Methods: Scheme of the nitrogen model HERMES

Scenarios for the evaluation of agro-environmental measures

Agriculture:• conventional arable management (= reference for no agro-environmental measures)• Organic farming (with actual live stock density)• pasture intensive• grassland extensive• set aside

Grounwater level (water management)• 6 constant gw distances: 30, 60, 100, 150, 200, 500 cm below ground

all variants were simulated for • 8 soil types• 5 climatic zones with representative stations and years

Smallest common geometry after intersection of soil map, gr.water map, CORINE land cover, field block map - > ca. 420.000 polygons

Simulation of cases:8 soils x 6 gw-levels x 8 livestock density classes x 5 land use systems x 5 climates = 9600 cases

0 - 2 0

6 5 - 8 0 > 8 0

N - A u s t r a g ( k g / h a * a ) a u s d e r W u r z e l z o n e

K e i n e A c k e r n u t z u n g / k e i n e D a t e n

2 0 - 3 5

5 0 - 6 5

0

3 5 - 5 0 organic farming

pasture extensive

arable land conventional

pasture intensive

Simulated N-leaching for conventional and extensive management systems (100% Scenarios)

FundamentalsMedium range soil mapGroundwater distances: HYM 50/DEM 25weather: DWD representative stationsLand use: Corine / biotope typesfertilization: Brandenburg Agro ReportLive stock density: Agricultural statistics

N leaching from root zone[kg N ha-1]

no agriculture/no dataBerlin

Simulated nitrate leaching from the root zone of agricultural used land in Brandenburg considering the actual percentage of agro-environmental measures

FundamentalsMedium range soil mapGroundwater distances: HYM 50/DEM 25weather: DWD representative stationsLand use: Corine / biotope typesfertilization: Brandenburg Agro ReportLive stock density: Agricultural statistics Agro-enironmv. measures: InVeKos data

Nitrate leaching [kg N ha-1]

non agricultural land

no leaching

Model based estimation of the site specific nitrate leaching risk (according to Federal State Soil Research, Lower Saxony Hannover)

Main land use type and soil texture field capacity of eff.root zone (FCrt)

Weather data, soil, land use simulation groundwater recharge (GWR)

GWR [mm year-1] Soil solution exchange frequency [% year-1] = x 100 (ExF)

FCrt [mm year-1]

Assessment of the downward displacement respectively nitrate leaching risk:

ExF [% year-1] < 70 70 - < 100 100 - <150 150 - <250 > 250

Risk very low low medium high very high

Exchange frequency 1*a-1 in % coverage of

aquifer < 70 70-100 100-150 150-250 > 250

covered very low very low low low medium partly covered very low low medium medium high

not covered very low low medium high very high

Assessment of potential risk for groundwater pollution

Estimation of areas with high impact risk for groundwater

very low

very highnon agricultural land

low

high

medium

vulnerability

N leaching risk

Klassen der Relevanz

0 (sehr wenig relevant)

1 (wenig relevant)

2 (mittel relevant)

3 (sehr relevant)

4 (äußerst relevant)

Kersebaum, Steidl, Kiesel

Potential risk for groundwater pollution with nitrogen in Brandenburg

Risk classes

0 (very low risk)

1 (low risk)

2 (medium risk)

3 (high risk)

4 very high risk)

Assessment of surface water pollution risk based on travel times

Acc. to Steidl, 2001

ditches

groundwater affected sites

riverrecharge areas

wetdraine

dsites

pollution risk small very high

weightingfactor:

transit time years

high

( x leaching root zone)

very high

classes of potential impact

High relevancerelevantsmall relevancesmall relevance,if GW-distance controlled

not relevant

Non agricultural land

Not evaluated

Classification of Brandenburg regarding the potential impact on surface water for nitrogen pollution

fundamentals: Travel time analysis(Kunkel & Wendland, 1999)N-decay in aquifer(Wendland & Kunkel, 1999)

Effects of the present agro-environmental measures in Brandenburg regarding the reduction of nitrogen leaching

non agricultural land

rivers

lakes

no effectReduction of N leaching [kg N ha-1]

Distribution of agro-environmental measures (AEM) between areas vulnerable or non-vulnerable for nutrient pollution of water resources

non vulnerable areasAEM in non vulnerable areasnot estimatedvulnerable areasAEM in vulnerable areas

Summary

o simulations based on spatial agro-meteorological information can be used for the site specific assessment of agricultural management effects regarding water pollution.

o evaluation of agro-environmental measures considering the targets of the EU Water Framework Directive requires a characteristic of sites regarding their potential impact on ground and surface water.

o evaluation of agro-environmental measures in Brandenburg showed that the measures are effective in most of the cases to reduce nitrogen leaching from the root zone. Nevertheless, 75% of the

measures were placed in areas with low impact on the water resources.

o the effect of the present agro-environmental measures regarding the aims of the Water Framework Directive are therefore not at an optimum.

o the method gives a good indication for a targeted allocation of measures and can be used as a basis for the development of measure plans to enhance the effectiveness for the improvement of water quality.

Thank you for your attention