Projecting future nitrogen inputs: are we making the right assumptions?
Global use of reactive nitrogen (N) has increased over the past century to meet growing food and biofuel demand, while contributing to substantial environmental impacts. Addressing continued N management challenges requires anticipating pathways of future N use. Several studies in the scientific lit...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2022-01-01
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| Series: | Environmental Research Letters |
| Subjects: | |
| Online Access: | https://doi.org/10.1088/1748-9326/ac6619 |
| _version_ | 1797746995368034304 |
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| author | Srishti Vishwakarma Xin Zhang Nathaniel D Mueller |
| author_facet | Srishti Vishwakarma Xin Zhang Nathaniel D Mueller |
| author_sort | Srishti Vishwakarma |
| collection | DOAJ |
| description | Global use of reactive nitrogen (N) has increased over the past century to meet growing food and biofuel demand, while contributing to substantial environmental impacts. Addressing continued N management challenges requires anticipating pathways of future N use. Several studies in the scientific literature have projected future N inputs for crop production under a business-as-usual scenario. However, it remains unclear how using yield response functions to characterize a given level of technology and management practices (TMP) will alter the projections when using a consistent dataset. In this study, to project N inputs to 2050, we developed and tested three approaches, namely ‘Same nitrogen use efficiency (NUE)’, ‘Same TMP’, and ‘Improving TMP’. We found the approach that considers diminishing returns in yield response functions (‘Same TMP’) resulted in 268 Tg N yr ^−1 of N inputs, which was 61 and 48 Tg N yr ^−1 higher than when keeping NUE at the current level with and without considering changes in crop mix, respectively. If TMP continue to evolve at the pace of past five decades, projected N inputs reduce to 204 Tg N yr ^−1 , a value that is still 59 Tg N yr ^−1 higher than the inputs in the baseline year 2006. Overall, our results suggest that assuming a constant NUE may be too optimistic in projecting N inputs, and the full range of projection assumptions need to be carefully explored when investigating future N budgets. |
| first_indexed | 2024-03-12T15:44:48Z |
| format | Article |
| id | doaj.art-297ea731b77745ecbf8c069f20a926da |
| institution | Directory Open Access Journal |
| issn | 1748-9326 |
| language | English |
| last_indexed | 2024-03-12T15:44:48Z |
| publishDate | 2022-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | Environmental Research Letters |
| spelling | doaj.art-297ea731b77745ecbf8c069f20a926da2023-08-09T15:29:06ZengIOP PublishingEnvironmental Research Letters1748-93262022-01-0117505403510.1088/1748-9326/ac6619Projecting future nitrogen inputs: are we making the right assumptions?Srishti Vishwakarma0https://orcid.org/0000-0003-1674-4197Xin Zhang1https://orcid.org/0000-0003-1619-1537Nathaniel D Mueller2https://orcid.org/0000-0003-1857-5104Appalachian Laboratory, University of Maryland Center for Environmental Science , Frostburg, MD, United States of AmericaAppalachian Laboratory, University of Maryland Center for Environmental Science , Frostburg, MD, United States of AmericaDepartment of Ecosystem Science and Sustainability, Colorado State University , Fort Collins, CO, United States of America; Department of Soil and Crop Sciences, Colorado State University , Fort Collins, CO, United States of AmericaGlobal use of reactive nitrogen (N) has increased over the past century to meet growing food and biofuel demand, while contributing to substantial environmental impacts. Addressing continued N management challenges requires anticipating pathways of future N use. Several studies in the scientific literature have projected future N inputs for crop production under a business-as-usual scenario. However, it remains unclear how using yield response functions to characterize a given level of technology and management practices (TMP) will alter the projections when using a consistent dataset. In this study, to project N inputs to 2050, we developed and tested three approaches, namely ‘Same nitrogen use efficiency (NUE)’, ‘Same TMP’, and ‘Improving TMP’. We found the approach that considers diminishing returns in yield response functions (‘Same TMP’) resulted in 268 Tg N yr ^−1 of N inputs, which was 61 and 48 Tg N yr ^−1 higher than when keeping NUE at the current level with and without considering changes in crop mix, respectively. If TMP continue to evolve at the pace of past five decades, projected N inputs reduce to 204 Tg N yr ^−1 , a value that is still 59 Tg N yr ^−1 higher than the inputs in the baseline year 2006. Overall, our results suggest that assuming a constant NUE may be too optimistic in projecting N inputs, and the full range of projection assumptions need to be carefully explored when investigating future N budgets.https://doi.org/10.1088/1748-9326/ac6619nitrogen budgetnitrogen use efficiencyprojection scenariostechnology and management practicescrop mixyield response functions |
| spellingShingle | Srishti Vishwakarma Xin Zhang Nathaniel D Mueller Projecting future nitrogen inputs: are we making the right assumptions? Environmental Research Letters nitrogen budget nitrogen use efficiency projection scenarios technology and management practices crop mix yield response functions |
| title | Projecting future nitrogen inputs: are we making the right assumptions? |
| title_full | Projecting future nitrogen inputs: are we making the right assumptions? |
| title_fullStr | Projecting future nitrogen inputs: are we making the right assumptions? |
| title_full_unstemmed | Projecting future nitrogen inputs: are we making the right assumptions? |
| title_short | Projecting future nitrogen inputs: are we making the right assumptions? |
| title_sort | projecting future nitrogen inputs are we making the right assumptions |
| topic | nitrogen budget nitrogen use efficiency projection scenarios technology and management practices crop mix yield response functions |
| url | https://doi.org/10.1088/1748-9326/ac6619 |
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