Elevated soil nitrogen pools after conversion of turfgrass to water-efficient residential landscapes
As a result of uncertain resource availability and growing populations, city managers are implementing conservation plans that aim to provide services for people while reducing household resource use. For example, in the US, municipalities are incentivizing homeowners to replace their water-intensiv...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2016-01-01
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| Series: | Environmental Research Letters |
| Subjects: | |
| Online Access: | https://doi.org/10.1088/1748-9326/11/8/084007 |
| _version_ | 1797748503538040832 |
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| author | Hannah Heavenrich Sharon J Hall |
| author_facet | Hannah Heavenrich Sharon J Hall |
| author_sort | Hannah Heavenrich |
| collection | DOAJ |
| description | As a result of uncertain resource availability and growing populations, city managers are implementing conservation plans that aim to provide services for people while reducing household resource use. For example, in the US, municipalities are incentivizing homeowners to replace their water-intensive turfgrass lawns with water-efficient landscapes consisting of interspersed drought-tolerant shrubs and trees with rock or mulch groundcover (e.g. xeriscapes, rain gardens, water-wise landscapes). While these strategies are likely to reduce water demand, the consequences for other ecosystem services are unclear. Previous studies in controlled, experimental landscapes have shown that conversion from turfgrass to shrubs may lead to high rates of nutrient leaching from soils. However, little is known about the long-term biogeochemical consequences of this increasingly common land cover change across diverse homeowner management practices. We explored the fate of soil nitrogen (N) across a chronosequence of land cover change from turfgrass to water-efficient landscapes in privately owned yards in metropolitan Phoenix, Arizona, in the arid US Southwest. Soil nitrate ( ${{{\rm{NO}}}_{3}}^{-}$ –N) pools were four times larger in water-efficient landscapes (25 ± 4 kg ${{{\rm{NO}}}_{3}}^{-}$ –N/ha; 0–45 cm depth) compared to turfgrass lawns (6 ± 7 kg ${{{\rm{NO}}}_{3}}^{-}$ –N/ha). Soil ${{{\rm{NO}}}_{3}}^{-}$ –N also varied significantly with time since landscape conversion; the largest pools occurred at 9–13 years after turfgrass removal and declined to levels comparable to turfgrass thereafter. Variation in soil ${{{\rm{NO}}}_{3}}^{-}$ –N with landscape age was strongly influenced by management practices related to soil water availability, including shrub cover, sub-surface plastic sheeting, and irrigation frequency. Our findings show that transitioning from turfgrass to water-efficient residential landscaping can lead to an accumulation of ${{{\rm{NO}}}_{3}}^{-}$ –N that may be lost from the plant rooting zone over time following irrigation or rainfall. These results have implications for best management practices to optimize the benefits of water-conserving landscapes while protecting water quality. |
| first_indexed | 2024-03-12T16:06:44Z |
| format | Article |
| id | doaj.art-94d39f21c6e3477286fbb16207fbd442 |
| institution | Directory Open Access Journal |
| issn | 1748-9326 |
| language | English |
| last_indexed | 2024-03-12T16:06:44Z |
| publishDate | 2016-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | Environmental Research Letters |
| spelling | doaj.art-94d39f21c6e3477286fbb16207fbd4422023-08-09T14:20:37ZengIOP PublishingEnvironmental Research Letters1748-93262016-01-0111808400710.1088/1748-9326/11/8/084007Elevated soil nitrogen pools after conversion of turfgrass to water-efficient residential landscapesHannah Heavenrich0Sharon J Hall1School of Life Sciences, Arizona State University , Tempe, Arizona 85287-4501 USASchool of Life Sciences, Arizona State University , Tempe, Arizona 85287-4501 USAAs a result of uncertain resource availability and growing populations, city managers are implementing conservation plans that aim to provide services for people while reducing household resource use. For example, in the US, municipalities are incentivizing homeowners to replace their water-intensive turfgrass lawns with water-efficient landscapes consisting of interspersed drought-tolerant shrubs and trees with rock or mulch groundcover (e.g. xeriscapes, rain gardens, water-wise landscapes). While these strategies are likely to reduce water demand, the consequences for other ecosystem services are unclear. Previous studies in controlled, experimental landscapes have shown that conversion from turfgrass to shrubs may lead to high rates of nutrient leaching from soils. However, little is known about the long-term biogeochemical consequences of this increasingly common land cover change across diverse homeowner management practices. We explored the fate of soil nitrogen (N) across a chronosequence of land cover change from turfgrass to water-efficient landscapes in privately owned yards in metropolitan Phoenix, Arizona, in the arid US Southwest. Soil nitrate ( ${{{\rm{NO}}}_{3}}^{-}$ –N) pools were four times larger in water-efficient landscapes (25 ± 4 kg ${{{\rm{NO}}}_{3}}^{-}$ –N/ha; 0–45 cm depth) compared to turfgrass lawns (6 ± 7 kg ${{{\rm{NO}}}_{3}}^{-}$ –N/ha). Soil ${{{\rm{NO}}}_{3}}^{-}$ –N also varied significantly with time since landscape conversion; the largest pools occurred at 9–13 years after turfgrass removal and declined to levels comparable to turfgrass thereafter. Variation in soil ${{{\rm{NO}}}_{3}}^{-}$ –N with landscape age was strongly influenced by management practices related to soil water availability, including shrub cover, sub-surface plastic sheeting, and irrigation frequency. Our findings show that transitioning from turfgrass to water-efficient residential landscaping can lead to an accumulation of ${{{\rm{NO}}}_{3}}^{-}$ –N that may be lost from the plant rooting zone over time following irrigation or rainfall. These results have implications for best management practices to optimize the benefits of water-conserving landscapes while protecting water quality.https://doi.org/10.1088/1748-9326/11/8/084007turfgrassnitrate leachingalternative landscapexeriscapeurban ecosystemwater quality and conservation |
| spellingShingle | Hannah Heavenrich Sharon J Hall Elevated soil nitrogen pools after conversion of turfgrass to water-efficient residential landscapes Environmental Research Letters turfgrass nitrate leaching alternative landscape xeriscape urban ecosystem water quality and conservation |
| title | Elevated soil nitrogen pools after conversion of turfgrass to water-efficient residential landscapes |
| title_full | Elevated soil nitrogen pools after conversion of turfgrass to water-efficient residential landscapes |
| title_fullStr | Elevated soil nitrogen pools after conversion of turfgrass to water-efficient residential landscapes |
| title_full_unstemmed | Elevated soil nitrogen pools after conversion of turfgrass to water-efficient residential landscapes |
| title_short | Elevated soil nitrogen pools after conversion of turfgrass to water-efficient residential landscapes |
| title_sort | elevated soil nitrogen pools after conversion of turfgrass to water efficient residential landscapes |
| topic | turfgrass nitrate leaching alternative landscape xeriscape urban ecosystem water quality and conservation |
| url | https://doi.org/10.1088/1748-9326/11/8/084007 |
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