Suitability of walnut and pistachio shells as soilless substrates for producing Genovese basil in aquaponic systems
IntroductionThe use of agricultural by-products, such as walnut and pistachio shells, is emerging as a sustainable substrate alternative to conventional substrates in soilless farming systems like hydroponics and aquaponics. These materials offer a promising solution for agri-waste management while...
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Frontiers Media S.A.
2025-07-01
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| Series: | Frontiers in Horticulture |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fhort.2025.1486312/full |
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| author | Gina P. Suárez-Cáceres Sandamali Lokuhitige Nathan T. Kaufman Alharith Alghaithy Mikaila B. Hishaw Irwin R. Donis-Gonzalez Víctor M. Fernández-Cabanás Jackson A. Gross |
| author_facet | Gina P. Suárez-Cáceres Sandamali Lokuhitige Nathan T. Kaufman Alharith Alghaithy Mikaila B. Hishaw Irwin R. Donis-Gonzalez Víctor M. Fernández-Cabanás Jackson A. Gross |
| author_sort | Gina P. Suárez-Cáceres |
| collection | DOAJ |
| description | IntroductionThe use of agricultural by-products, such as walnut and pistachio shells, is emerging as a sustainable substrate alternative to conventional substrates in soilless farming systems like hydroponics and aquaponics. These materials offer a promising solution for agri-waste management while advancing circular economy objectives in sustainable agriculture.MethodsThe present study evaluates the performance of crushed walnut shell (CWS) and line-waste pistachio shell (LWPS) as partial to complete replacements for coconut coir (CC) in decoupled aquaponic systems, using Genovese basil (Ocimum basilicum) as a model crop. Two independent experiments were conducted concurrently, one for each nutshell substrate (n=6 replicate trays). Each experiment included nine treatments: a control group (50% peat moss/50% perlite), four nutshell-based blends (10%, 25%, 33%, and 50% of either CWS or LWPS), and four CC-based blends at the same inclusion rates. Plant growth metrics, including height, number of nodes and leaves, SPAD chlorophyll index, fresh and dry shoot weight, and root development were measured to assess treatment performance.ResultsOverall, basil grown in lower inclusion rates of CWS and LWPS media performed comparably to those grown in CC-based media. However, growth suppression was observed in the 33% and 50% CWS treatments, likely due to juglone toxicity. In contrast, LWPS exhibited a modest growth benefit at 25%, before declining at higher levels, which may be acributed to reduced water holding capacity.DiscussionThese findings suggest that walnut and pistachio shells can serve as effective components of soilless growing media when used at moderate inclusion rates. While higher concentrations presented limitations, low to moderate inclusion levels yielded growth performance comparable to that of CC. These findings support the potential of regionally sourced nutshell by-products as viable alternatives to imported growing media, contributing to a more diversified and resilient horticultural supply chain. |
| format | Article |
| id | doaj-art-eb18aea195e94f5bb9fdc0ccb0cb9c99 |
| institution | DOAJ |
| issn | 2813-3595 |
| language | English |
| publishDate | 2025-07-01 |
| publisher | Frontiers Media S.A. |
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| series | Frontiers in Horticulture |
| spelling | doaj-art-eb18aea195e94f5bb9fdc0ccb0cb9c992025-08-20T03:12:50ZengFrontiers Media S.A.Frontiers in Horticulture2813-35952025-07-01410.3389/fhort.2025.14863121486312Suitability of walnut and pistachio shells as soilless substrates for producing Genovese basil in aquaponic systemsGina P. Suárez-Cáceres0Sandamali Lokuhitige1Nathan T. Kaufman2Alharith Alghaithy3Mikaila B. Hishaw4Irwin R. Donis-Gonzalez5Víctor M. Fernández-Cabanás6Jackson A. Gross7Urban Greening and Biosystems Engineering Research Group, Departamento de Agronomía, Universidad de Sevilla, Escuela Téchnica Superior en Ingenierı́a Agronómica (ETSIA), Seville, SpainDepartment of Animal Sciences, University of California, Davis, Davis, CA, United StatesDepartment of Animal Sciences, University of California, Davis, Davis, CA, United StatesDepartment of Agriculture and Biological Engineering, University of California, Davis, Davis, CA, United StatesDepartment of Animal Sciences, University of California, Davis, Davis, CA, United StatesDepartment of Agriculture and Biological Engineering, University of California, Davis, Davis, CA, United StatesUrban Greening and Biosystems Engineering Research Group, Departamento de Agronomía, Universidad de Sevilla, Escuela Téchnica Superior en Ingenierı́a Agronómica (ETSIA), Seville, SpainDepartment of Animal Sciences, University of California, Davis, Davis, CA, United StatesIntroductionThe use of agricultural by-products, such as walnut and pistachio shells, is emerging as a sustainable substrate alternative to conventional substrates in soilless farming systems like hydroponics and aquaponics. These materials offer a promising solution for agri-waste management while advancing circular economy objectives in sustainable agriculture.MethodsThe present study evaluates the performance of crushed walnut shell (CWS) and line-waste pistachio shell (LWPS) as partial to complete replacements for coconut coir (CC) in decoupled aquaponic systems, using Genovese basil (Ocimum basilicum) as a model crop. Two independent experiments were conducted concurrently, one for each nutshell substrate (n=6 replicate trays). Each experiment included nine treatments: a control group (50% peat moss/50% perlite), four nutshell-based blends (10%, 25%, 33%, and 50% of either CWS or LWPS), and four CC-based blends at the same inclusion rates. Plant growth metrics, including height, number of nodes and leaves, SPAD chlorophyll index, fresh and dry shoot weight, and root development were measured to assess treatment performance.ResultsOverall, basil grown in lower inclusion rates of CWS and LWPS media performed comparably to those grown in CC-based media. However, growth suppression was observed in the 33% and 50% CWS treatments, likely due to juglone toxicity. In contrast, LWPS exhibited a modest growth benefit at 25%, before declining at higher levels, which may be acributed to reduced water holding capacity.DiscussionThese findings suggest that walnut and pistachio shells can serve as effective components of soilless growing media when used at moderate inclusion rates. While higher concentrations presented limitations, low to moderate inclusion levels yielded growth performance comparable to that of CC. These findings support the potential of regionally sourced nutshell by-products as viable alternatives to imported growing media, contributing to a more diversified and resilient horticultural supply chain.https://www.frontiersin.org/articles/10.3389/fhort.2025.1486312/fullagricultural by productsaquaponicscircular economyhydroponicsOcimum basilicumsoilless production |
| spellingShingle | Gina P. Suárez-Cáceres Sandamali Lokuhitige Nathan T. Kaufman Alharith Alghaithy Mikaila B. Hishaw Irwin R. Donis-Gonzalez Víctor M. Fernández-Cabanás Jackson A. Gross Suitability of walnut and pistachio shells as soilless substrates for producing Genovese basil in aquaponic systems Frontiers in Horticulture agricultural by products aquaponics circular economy hydroponics Ocimum basilicum soilless production |
| title | Suitability of walnut and pistachio shells as soilless substrates for producing Genovese basil in aquaponic systems |
| title_full | Suitability of walnut and pistachio shells as soilless substrates for producing Genovese basil in aquaponic systems |
| title_fullStr | Suitability of walnut and pistachio shells as soilless substrates for producing Genovese basil in aquaponic systems |
| title_full_unstemmed | Suitability of walnut and pistachio shells as soilless substrates for producing Genovese basil in aquaponic systems |
| title_short | Suitability of walnut and pistachio shells as soilless substrates for producing Genovese basil in aquaponic systems |
| title_sort | suitability of walnut and pistachio shells as soilless substrates for producing genovese basil in aquaponic systems |
| topic | agricultural by products aquaponics circular economy hydroponics Ocimum basilicum soilless production |
| url | https://www.frontiersin.org/articles/10.3389/fhort.2025.1486312/full |
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