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Land Use Changes - Coggle Diagram
Land Use Changes
Farming
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Carbon storage reduced due to forest clearance for farmland space. Carbon storage in soil reduced due to oxidation of organic matter and ploughing.
Erosion by wind and water is most severe when crops have been lifted and soil has no protective cover.
Crop irrigation diverts surface water from rivers to cultivated land. Some is extracted by crops and released via transpiration and some is lost to evaporation and soil drainage.
Surface run off increased when heavy machinery compacts the soil. Contour ploughing (horizontal) decreases surface run off, ploughing downhill increases surface run off.
Interception, evaporation and transpiration are decreased compared to in forest and grassland ecosystems but ploughing increases evaporation and soil moisture loss.
Forestry
Increased interception rates ~ conifers have needle-like leaves, evergreen habits and are planted in a high density.
Increased evaporation and transpiration. Reduced run-off and stream discharge due to high interception.
Sudden, temporary changes when timber is felled: increased run-off and stream discharge, decreased evapotranspiration.
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Amount of carbon captured levels off and is balanced by inputs of litter into soil, release of CO2 in respiration and by soil decomposes.
Most carbon is stored in the wood of the tree stem but trees only become an active carbon sink for the 1st 100 years after planting.
Urbanisation
Urban areas have drainage systems which help to remove surface water quickly but this can cause a increase in water level as water from rain goes directly into streams and rivers.
Structures are also built on / near floodplains so water storage capacity is reduced (as no space for water) so increased flood risk.
Artificial surfaces are impermeable so water cannot infiltrate them. They provide no storage for buffer run-off.