Water Pollution Monitoring Of Nitrates Leaching From Agricultural Fields With Industrial Crop Harvesting Practices. The Belgian Case Of Onsite Lysimeters

As A Monitoring Tool. Fonder Nathalie (1), Jean Marie Marcoen(2),

Dimitri Xanthoulis (3)

(1) Epuvaleau npo, Avenue de la Faculté d’Agronomie, 5030 Gembloux ; fonder@epuvaleau.eu(2) GRENeRA, Geopedology Laboratory, Gembloux Agricultural University, Passage des déportés, 2, 5030 Gembloux ; JM.Marcoen@ulg.ac.be;(3) Gembloux Agricultural University, Department of Hydrology and Rural Hydraulics, Passage des déportés, 2, 5030 Gembloux ;

d.xanthoulis@ulg.ac.be

OUTLINESClimate : Cold Temperate, ocean influenced

Latitude : 52°N

Annual Temperature : 10°C

Rainfall : 800-1200 mm/yr

Rain Frequency : 200 days/yr

Belgium is a Kingdom with FEDERAL STATE GOV.

3 Communities, corresponding to population groups (language and culture)

3 Regions corresponding to economic autonomy desires

(In charge of Agriculture and Water management, amongst other)

Federal Government manage Army, Foreign Affairs, Public Health, Justice, Finance, Social Security, etc.

6 Mi Inh

1 Mi Inh

3,5 MI Inh

Area = 32500 KM2

Pop. 10,5 Mi Inh.

Density 315 Inh/Km2

Context

1991 : European Nitrate Directive (91/676/CEE) aims at moderating or preventing water pollution from nitrates released by agricultural practices

2000 : creation of NITRAWAL, npo as a consortium of 4 partners to provide support to farmers (1 from Water sector, 1 from agricultural sector, 2 scientific partners from Walloon universities – GRENeRA, ECOP)

2002 : Transposition into the Wallon law with the PGDA (Programme de Gestion Durable de l’Azote) / Sustainable Nitrogen Management Program

- standards on mineral and organic fertilization rates- agricultural practices code

2005 : Condemnation by EU for non complete transcription- PGDA review process

2007 : New PGDA having impacts on the operation managements by farmers

2003 – now : scientific studies- test the relevance of the environmental indicator defined,- adequacy standards / water quality preservation,- advices on crop rotation and sequences

Material and method

Data collection

Crops rotation above lysimeters implementation

Plots / Years

P1 P2 P3 P4 P5

2002 Sugar beets Sugar beets Spinach / Beans Wheat Broad Beans / Chervil

2003 Wheat + Inset crop

Broad Beans / Cabbages

Flax + Inset crop

Sugar beets Wheat + Inset crop

2004 Beans Spinach / Beans + Inset crop

Broad Beans / Cabbages

Wheat + Inset crop

Sugar beets

2005 Wheat + Inset crop

Chicories Carrots Broad Beans Wheat + Inset crop

2006 Broad Beans / Spinach

Wheat Potatoes Wheat + Inset crop

Haricots

2007 Wheat Carrots Sugar beets Beans Wheat + Inset crop

2008 Carrots Broad Beans / Cabbages

Wheat Wheat + Inset crop

Sugar beets

2009 Beans Leeks Broad Beans Broad Beans Wheat

Results for Water Quantity

Water Budget :

Water collected = Infiltration water

In Wallonia : Pluviometry = 100%, Infiltration = 6 to 28%

In Lysimeters,

Water collected = P + I – ETM (assumption to have a closed lysimeter)

P= Pluviometry

I = Irrigation

ETM= ET * Kc (cultural coefficient)

Results obtained over 5 drainage seasons = 12 to 14%

The Walloon Environmental indicator APL

APL = Azote Potentiellement Lessivable / Potentially Leachable Nitrogen

Issued from the “Survey Surface Agricole” (Agricultural Surface Survey) - 25 farms

- total of 220 fields

Annual sampling - first at spring, leading to fertilisation rate recommendations

- secondly at autumn, to assess residue after harvest

Annual APL (Environmental Indicator) is defined per crops and their related acceptable nitrogen residue in the soil after harvest.

If above, - penalties for the farmers

Lysimeter project : no plots received any negative assessment from the Environmental indicator

Nevertheless, high to very high values of nitrate content are observed in lysimeters

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AP

L (k

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APL 60-90 cm (kg N-NO3/ha) APL 30-60 cm (kg N-NO3/ha)

APL 0-30 cm (kg N-NO3/ha) cc NO3- (mg/l)

cumulative collected volume (l)

Plot P1Disturbed soil lysimeterimplementation on 8 August 2003

Crops

Wheat Carrots

N Fertilisation

2004 20082003

Spinach

66 U N-min

97 U N-min

B BeansPhaceliaWheatBeansOat

80 U N-min

58 U N-min

78 U N-min

65 U N-min

58 U N-min200 U N-org

2005 2006 2007

Wheat

WHO Drinking water standard (50 mg NO3-/L)

Summary Table for Water Quality

Conclusion and recommendation

- Lysimeters are reliable to collect representative seepage water amounts

- Lysimeters confirm the reliability of APL Environmental Indicator

- Unfortunately, respect of legislation ≠ water quality preservation

- N management has to be defined over the whole crop rotation sequence and not per individual crops

Conclusion and recommendation-Cereals + inset crop / without OK / non OK

- Sugar beet OK

- Potato with no winter cover non OK

- Any vegetable should have a winter cover crop

- Spinach + beans (+ inset crop) non OK (OK)

- Broad beans + Spinach or cabbage or wheat non OK

Works in progress investigate :

- specific crop sequences and rotations,

- fertilisation recommendation rates for the different crops grown in the Belgian Walloon region

THANK YOU FOR

YOUR ATTENTION