Impacts of Shade Trees on the Adjacent Cacao Rhizosphere in a Young Diversified Agroforestry System
Cacao agroforestry systems offer the potential to diversify farmer income sources, enhance biodiversity, sequester carbon, and deliver other important ecosystem services. To date, however, studies have emphasized field- and system-scale outcomes of shade tree integration, and potential impacts on th...
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-01-01
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| Series: | Agronomy |
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| Online Access: | https://www.mdpi.com/2073-4395/12/1/195 |
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| author | Jennifer E. Schmidt Alana Firl Hamran Hamran Nur Insana Imaniar Taylor M. Crow Samantha J. Forbes |
| author_facet | Jennifer E. Schmidt Alana Firl Hamran Hamran Nur Insana Imaniar Taylor M. Crow Samantha J. Forbes |
| author_sort | Jennifer E. Schmidt |
| collection | DOAJ |
| description | Cacao agroforestry systems offer the potential to diversify farmer income sources, enhance biodiversity, sequester carbon, and deliver other important ecosystem services. To date, however, studies have emphasized field- and system-scale outcomes of shade tree integration, and potential impacts on the rhizosphere of adjacent cacao trees have not been fully characterized. Interactions at the root–soil interface are closely linked to plant health and productivity, making it important to understand how diverse shade tree species may affect soil fertility and microbial communities in the cacao rhizosphere. We assessed the impacts of neighboring shade tree presence and identity on cacao yields and physical, chemical, and biological components of the cacao rhizosphere in a recently established diversified agroforestry system in South Sulawesi, Indonesia. Stepwise regression revealed surprising and strong impacts of microbial diversity and community composition on cacao yields and pod infection rates. The presence of neighboring shade trees increased nitrogen, phosphorus, and pH in the rhizosphere of nearby cacao trees without yield losses. Over a longer time horizon, these increases in rhizosphere soil fertility will likely increase cacao productivity and shape microbial communities, as regression models showed nitrogen and phosphorus in particular to be important predictors of cacao yields and microbiome diversity and composition. However, neither presence nor identity of shade trees directly affected microbial diversity, community composition, or field-scale distance-decay relationships at this early stage of establishment. These results highlight locally specific benefits of shade trees in this agroecological context and emphasize the rhizosphere as a key link in indirect impacts of shade trees on cacao health and productivity in diversified systems. |
| first_indexed | 2024-03-10T03:05:17Z |
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| institution | Directory Open Access Journal |
| issn | 2073-4395 |
| language | English |
| last_indexed | 2024-03-10T03:05:17Z |
| publishDate | 2022-01-01 |
| publisher | MDPI AG |
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| series | Agronomy |
| spelling | doaj.art-09c8726fad964fadb7e3a3fa190f952f2023-11-23T12:39:49ZengMDPI AGAgronomy2073-43952022-01-0112119510.3390/agronomy12010195Impacts of Shade Trees on the Adjacent Cacao Rhizosphere in a Young Diversified Agroforestry SystemJennifer E. Schmidt0Alana Firl1Hamran Hamran2Nur Insana Imaniar3Taylor M. Crow4Samantha J. Forbes5Cocoa Plant Sciences, Mars Wrigley, Davis, CA 95616, USACocoa Plant Sciences, Mars Wrigley, Davis, CA 95616, USAMars Indonesia, KIMA X Kav A6, Makassar 90241, IndonesiaMars Indonesia, KIMA X Kav A6, Makassar 90241, IndonesiaCocoa Plant Sciences, Mars Wrigley, Davis, CA 95616, USAMars Sustainable Solutions, Cairns 4878, AustraliaCacao agroforestry systems offer the potential to diversify farmer income sources, enhance biodiversity, sequester carbon, and deliver other important ecosystem services. To date, however, studies have emphasized field- and system-scale outcomes of shade tree integration, and potential impacts on the rhizosphere of adjacent cacao trees have not been fully characterized. Interactions at the root–soil interface are closely linked to plant health and productivity, making it important to understand how diverse shade tree species may affect soil fertility and microbial communities in the cacao rhizosphere. We assessed the impacts of neighboring shade tree presence and identity on cacao yields and physical, chemical, and biological components of the cacao rhizosphere in a recently established diversified agroforestry system in South Sulawesi, Indonesia. Stepwise regression revealed surprising and strong impacts of microbial diversity and community composition on cacao yields and pod infection rates. The presence of neighboring shade trees increased nitrogen, phosphorus, and pH in the rhizosphere of nearby cacao trees without yield losses. Over a longer time horizon, these increases in rhizosphere soil fertility will likely increase cacao productivity and shape microbial communities, as regression models showed nitrogen and phosphorus in particular to be important predictors of cacao yields and microbiome diversity and composition. However, neither presence nor identity of shade trees directly affected microbial diversity, community composition, or field-scale distance-decay relationships at this early stage of establishment. These results highlight locally specific benefits of shade trees in this agroecological context and emphasize the rhizosphere as a key link in indirect impacts of shade trees on cacao health and productivity in diversified systems.https://www.mdpi.com/2073-4395/12/1/195agroforestrycacao (<i>Theobroma cacao</i>)diversificationmicrobiomerhizosphereshade trees |
| spellingShingle | Jennifer E. Schmidt Alana Firl Hamran Hamran Nur Insana Imaniar Taylor M. Crow Samantha J. Forbes Impacts of Shade Trees on the Adjacent Cacao Rhizosphere in a Young Diversified Agroforestry System Agronomy agroforestry cacao (<i>Theobroma cacao</i>) diversification microbiome rhizosphere shade trees |
| title | Impacts of Shade Trees on the Adjacent Cacao Rhizosphere in a Young Diversified Agroforestry System |
| title_full | Impacts of Shade Trees on the Adjacent Cacao Rhizosphere in a Young Diversified Agroforestry System |
| title_fullStr | Impacts of Shade Trees on the Adjacent Cacao Rhizosphere in a Young Diversified Agroforestry System |
| title_full_unstemmed | Impacts of Shade Trees on the Adjacent Cacao Rhizosphere in a Young Diversified Agroforestry System |
| title_short | Impacts of Shade Trees on the Adjacent Cacao Rhizosphere in a Young Diversified Agroforestry System |
| title_sort | impacts of shade trees on the adjacent cacao rhizosphere in a young diversified agroforestry system |
| topic | agroforestry cacao (<i>Theobroma cacao</i>) diversification microbiome rhizosphere shade trees |
| url | https://www.mdpi.com/2073-4395/12/1/195 |
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