Attenuation of urban agricultural production potential and crop water footprint due to shading from buildings and trees
Urban agriculture requires local water to replace ‘hydrologic externalities’ associated with food produced outside of the local area, with an accompanying shift of the water footprint (WF) for agricultural production from rural to urban areas. Water requirements of urban agriculture have been diffic...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2015-01-01
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| Series: | Environmental Research Letters |
| Subjects: | |
| Online Access: | https://doi.org/10.1088/1748-9326/10/6/064007 |
| _version_ | 1797748756004732928 |
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| author | Mark S Johnson Michael J Lathuillière Thoreau R Tooke Nicholas C Coops |
| author_facet | Mark S Johnson Michael J Lathuillière Thoreau R Tooke Nicholas C Coops |
| author_sort | Mark S Johnson |
| collection | DOAJ |
| description | Urban agriculture requires local water to replace ‘hydrologic externalities’ associated with food produced outside of the local area, with an accompanying shift of the water footprint (WF) for agricultural production from rural to urban areas. Water requirements of urban agriculture have been difficult to estimate due to the heterogeneity of shading from trees and buildings within urban areas. We developed CityCrop, a plant growth and evapotranspiration (ET) model that couples a 3D model of tree canopies and buildings derived from LiDAR with a ray-casting approach to estimate spatially-explicit solar inputs in combination with local climate data. Evaluating CityCrop over a 1 km ^2 mixed use, residential neighborhood of Vancouver Canada, we estimated median light attenuation to result in 12% reductions in both reference ET (ET _o ) and crop ET (ET _c ). However, median crop yields were reduced by only 3.5% relative to potential yield modeled without any light attenuation, while the median crop WF was 9% less than the WF for areas unimpeded by shading. Over the 75 day cropping cycle, median crop water requirements as ET _c were 17% less than that required for a well-watered grass (as ET _o ). If all lawns in our modeled area were replaced with crops, we estimate that about 37% of the resident population could obtain the vegetable portion of their diet from within the local area over a 150 day growing season. However doing so would result in augmented water demand if watering restrictions apply to lawns only. The CityCrop model can therefore be useful to evaluate trade-offs related to urban agriculture and to inform municipal water policy development. |
| first_indexed | 2024-03-12T16:10:22Z |
| format | Article |
| id | doaj.art-4f73bfc19b2f459694c3026b856f6149 |
| institution | Directory Open Access Journal |
| issn | 1748-9326 |
| language | English |
| last_indexed | 2024-03-12T16:10:22Z |
| publishDate | 2015-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | Environmental Research Letters |
| spelling | doaj.art-4f73bfc19b2f459694c3026b856f61492023-08-09T14:10:18ZengIOP PublishingEnvironmental Research Letters1748-93262015-01-0110606400710.1088/1748-9326/10/6/064007Attenuation of urban agricultural production potential and crop water footprint due to shading from buildings and treesMark S Johnson0Michael J Lathuillière1Thoreau R Tooke2Nicholas C Coops3Institute for Resources, Environment and Sustainability, University of British Columbia , 418-2202 Main Mall, Vancouver, British Columbia V6T 1Z4, Canada; Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia , Vancouver, BC, CanadaInstitute for Resources, Environment and Sustainability, University of British Columbia , 418-2202 Main Mall, Vancouver, British Columbia V6T 1Z4, CanadaFaculty of Forestry, University of British Columbia , 2424 Main Mall, Vancouver, BC V6T 1Z4, CanadaFaculty of Forestry, University of British Columbia , 2424 Main Mall, Vancouver, BC V6T 1Z4, CanadaUrban agriculture requires local water to replace ‘hydrologic externalities’ associated with food produced outside of the local area, with an accompanying shift of the water footprint (WF) for agricultural production from rural to urban areas. Water requirements of urban agriculture have been difficult to estimate due to the heterogeneity of shading from trees and buildings within urban areas. We developed CityCrop, a plant growth and evapotranspiration (ET) model that couples a 3D model of tree canopies and buildings derived from LiDAR with a ray-casting approach to estimate spatially-explicit solar inputs in combination with local climate data. Evaluating CityCrop over a 1 km ^2 mixed use, residential neighborhood of Vancouver Canada, we estimated median light attenuation to result in 12% reductions in both reference ET (ET _o ) and crop ET (ET _c ). However, median crop yields were reduced by only 3.5% relative to potential yield modeled without any light attenuation, while the median crop WF was 9% less than the WF for areas unimpeded by shading. Over the 75 day cropping cycle, median crop water requirements as ET _c were 17% less than that required for a well-watered grass (as ET _o ). If all lawns in our modeled area were replaced with crops, we estimate that about 37% of the resident population could obtain the vegetable portion of their diet from within the local area over a 150 day growing season. However doing so would result in augmented water demand if watering restrictions apply to lawns only. The CityCrop model can therefore be useful to evaluate trade-offs related to urban agriculture and to inform municipal water policy development.https://doi.org/10.1088/1748-9326/10/6/064007urban agriculturecrop water useevapotranspirationwater footprint92.40.Je Evapotranspiration92.40.Oj Eco-hydrology; plant ecology |
| spellingShingle | Mark S Johnson Michael J Lathuillière Thoreau R Tooke Nicholas C Coops Attenuation of urban agricultural production potential and crop water footprint due to shading from buildings and trees Environmental Research Letters urban agriculture crop water use evapotranspiration water footprint 92.40.Je Evapotranspiration 92.40.Oj Eco-hydrology; plant ecology |
| title | Attenuation of urban agricultural production potential and crop water footprint due to shading from buildings and trees |
| title_full | Attenuation of urban agricultural production potential and crop water footprint due to shading from buildings and trees |
| title_fullStr | Attenuation of urban agricultural production potential and crop water footprint due to shading from buildings and trees |
| title_full_unstemmed | Attenuation of urban agricultural production potential and crop water footprint due to shading from buildings and trees |
| title_short | Attenuation of urban agricultural production potential and crop water footprint due to shading from buildings and trees |
| title_sort | attenuation of urban agricultural production potential and crop water footprint due to shading from buildings and trees |
| topic | urban agriculture crop water use evapotranspiration water footprint 92.40.Je Evapotranspiration 92.40.Oj Eco-hydrology; plant ecology |
| url | https://doi.org/10.1088/1748-9326/10/6/064007 |
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