LEACHING OF NUTRIENTS FROM PEATLAND DRAINAGE Bjrn Klve Process and - - PowerPoint PPT Presentation

LEACHING OF NUTRIENTS FROM PEATLAND DRAINAGE

21.1.2014

Bjørn Kløve

Process and Environmental Engineering Department

Water Resources and Environmental Engineering Laboratory bjorn.klove@oulu.fi

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CONTENT

• Leaching from different peatland

uses and peat soil characteristics

• P leaching
• N leaching
• Hydrological controls
• Drainage depth
• Rainfall/snowmelt generated runoff

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Land cover typically consist of forests and peatlands, so water are often brown and humic!

WATER QUALITY AND ORGANIC SOILS

• Water tends to

be brown in color due to humic substances

• Varies based on

hydrology, land use, peat type, soil types etc

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PEAT SOILS: ACCUMULATION

• Several compounds have been accumulated in peat due

to plant growth and past geochemical environment (e.g. precipitation of Fe) catchment and groundwater properties

• Peat soils will have different content of Fe, P, metals etc.
• N? C?
• What happens after drainage?

How does drainage influence leaching? P , N, Fe, metals humic substances?

Björn Klöve, 19.4.2012

Peat harvesting

Leaching influenced by: Soil type Drainage depth Local climate Hydrology (temporal variation)

SUB SOIL INFLUENCE

• Sub soil influence water quality
• Erosion and SS transport
• Acide sulphide soils

PEATLAND CULTIVATION AND LEACHING

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On cultivated soils

• Good yield, high ET

, low runoff, less leaching

• Nutrients updtake by plants important
• Manure should not be applied

LEACHING

Pristine Drained Nutrient uptake Areation of peat, release of Some leaching nutriens flow patterns also from deep peat runoff and flooding release nutrients

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P

• High variation between sites in soil natural P and

P leaching potential after drainage

• P fertilization will result in P accumulation in top

soil layers

• P loads temporal variation
• high with low runoff from unfertilized peatlands
• Increase with runoff from cultivated sites?
• As from cultivated mineral soils?

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FE AND P IN DIFFERENT PEATLAND USES AT PELSO

0,00 0,50 1,00 1,50 2,00 2,50 3,00 0-15 45-60 kg / m3 Depth (cm)

Total P

0,00 0,50 1,00 1,50 2,00 2,50 3,00 0-15 45-60 Depth (cm)

Total Al

0,00 1,00 2,00 3,00 4,00 5,00 6,00 7,00 0-15 45-60 kg / m3 Depth (cm)

Total Fe

0,00 1,00 2,00 3,00 4,00 5,00 6,00 7,00 0-15 45-60 Depth (cm)

Total Ca

Cultivated peatland Peat extraction Peatland forest Pristine bog

Hyvärinen, Mustamo, Ronkanen ja Klöve 2012 julkaisematon aineisto

PHOSPHOROUS LEACHING

• P depends on soil and land

use (fertiilization)

• LAND USE EFFECTS:
• Cultivated sites: high P

with runoff

• Cutover peatlands:

high P in low flow

Kløve, B. 2001. Characteristics of nitrogen and phosphorus loads in peat mining wastewater. Water Research 35 (10), 2353-2362.

Björn Klöve, 19.4.2012

P LEACHING: PEAT HARVESTING

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0.05 0.1 0.15 0.2 0.25 0.3 100 200 300 400 500 600 700 Q (l/s) PO4-P in (mg/l)

0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 100 200 300 400 500 600 700 Q (l/s) Ptot in (mg/l)

PO4-P AND DRAINAGE DEPTH: PEAT HARVESTING

R2 = 0.3557

0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 20 40 60 80 100 120 Ojitussyvyys (cm) PO4-P in (mg/l)

Björn Klöve, 19.4.2012

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P rich soils due to deposition as P-Fe Vivianite

• High variation between sites

Fe(PO4)2 Fe3(Po4)2 · 8H2 2[Fe3(PO4)2 · 8H2O]

Björn Klöve, 19.4.2012

N

N leaching

• N released from peat
• N added as fertilizers
• N surplus and N in soil can

leach Peat harvesting:

• N leached as NH4-N and Org-

N and occasionally as NO3-N

• N leaching depends of

drainage, high on newly drained sites

• Difference between sites

probably smaller than with P leaching

Björn Klöve, 19.4.2012

N – PEAT HARVESTING

LEACHING AND RUNOFF: PEAT HARVEST.

• P high in old water rich in humus substances (peat harvesting=
• P probably high in runoff after cultivation
• NO3-N high in areated layers and released in high runoff events

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P ET P from PH NO3 ”old water” P arable land

KIITOS

Björn Klöve, 19.4.2012

Runoff through soil or not?

Snowmelt and leaching

HYDROLOGICAL PATHWAYS STUDIES

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Riku Eskelinen

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SNOW, FROST AND SNOWMELT

CONCLUSION FROM SNOW MELT RUNOFF STUDIES

• Snowmelt runoff, if soil is frozed, result in overland flow and

low nutrient concentration in runoff

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Low K, as water freezes Overland flow

LEACHING HYDROLOGY

• Drained site deep peat

Inundated

• Drained shallow peat

Sesonally flooded

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LEACHING OF NUTRIENTS: SUMMARY

• Variation between catchments due to

variation in land use, soil properties and to some extent climate

• On cultivated soils
• good yield, hihgh ET, low runoff, little

leaching

• Nutrients updtake by plants
• High temporal variation of nutrient

leaching due to interaction between climate-hydrology-soils-geochemistry- vegetation interaction

Björn Klöve, 19.4.2012 25

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Thank you for attention Acknoweldgements

• PhD researchers and other staff
• Recent funders: MMM, Vapo Oy, MVTT

, Nesssling, EU-EAKR programme etc.

WHY IMPORTANT TO KNOW ABOUT LACHING PROCESSES

• Nutrient input in surface waters can result

in reduced water quality

• When to reduce loading?
• Characteristics of loading must be known

for efficient removal

• Drainage influence P, N, metals and water

pH

• Environmental aspects in management
• ptions should consider leaching

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DRAINAGE

• Catchemnt runoff cut-off and nutrients

not trapped in peatlands

• Changes in hydrology, water chemistry,

vegetation if left alone

• Intense land use after drainage
• Water transport throught decomposed

soils

• Soils areated
• Organic matter decay
• pH increased
• Excepts on AS soils
• Sub soil influence
• ph, metals
• Erosion

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