Environmental Engineering Reference
In-Depth Information
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Canopy surface: represents the pesticide deposit on branches, leaves, fruits,
shoots and green parts (hence the outer part of the plant)
Plant: represents the agrochemical stored inside the plant
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Soil available fraction: the pesticide quantity which can move and can be
transformed by biotic processes
Soil aged fraction: the pesticide trapped within soil micro pores and organic
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matter and not available for transformation
Soil bound fraction: the pesticide fraction that cannot be extracted from the soil
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without altering its physical-chemical structure and therefore not available for
transformation
The models were implemented in four modules, representing environmental
compartments:
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Air considers the processes that happen before the product reaches the soil
including drift and plant interception.
Crop simulates only the plant mass balance, although in this first prototype plant
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is only a sink of pesticide.
Canopy simulates the processes that happen on the leaf surface.
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Soil describes the pesticide flow through the soil profile. Each soil profile has to
be split in numerical layers; the equations which describe the fate of pesticides
differ for the top and bottom layers, because there are different boundary
conditions.
The processes that redistribute the pesticide into the system connect two compartments
and are:
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Penetration: from canopy surface to plant
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Wash off; from canopy surface to soil available fraction
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Ageing: from soil available fraction to soil aged fraction and vice versa
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Binding: from soil available fraction to soil bound fraction
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Plant uptake: from soil available fraction to plant
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Transport in liquid and gaseous phase: between the soil available fraction
compartments of different layers
The output variables of greatest interest due to their importance for environmental
pollution are: amount of pesticide lost due to drift; amount of pesticide volatilized,
amount of pesticide lost due to run off, amount of pesticide lost to the drain system
when present, amount of pesticide leached, and amount of pesticide remaining in
the soil profile.
Crop: Crop Development and Growth
The crop component was developed by PPS and CIRAD. It simulates crop growth
and development for the major crops of Europe. Tropical crops are currently
being added. Crop growth is based on the interception of radiation by green plant
parts and its conversion into dry matter. Crop development goes through vegetative
