Native Grasses Enhance Topsoil Organic Carbon and Nitrogen by Improving Soil Aggregates and Microbial Communities in Navel Orange Orchards in China
In Gannan navel orange (<i>Citrus sinensis</i>) orchards—a typical sloped farmland ecosystem—selected native grasses outperform conventional green manure due to their stronger ecological adaptability and lower management requirements. However, few studies have investigated how native gra...
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| Main Authors: | , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-05-01
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| Series: | Horticulturae |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2311-7524/11/5/560 |
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| Summary: | In Gannan navel orange (<i>Citrus sinensis</i>) orchards—a typical sloped farmland ecosystem—selected native grasses outperform conventional green manure due to their stronger ecological adaptability and lower management requirements. However, few studies have investigated how native grasses enhance soil organic carbon and nitrogen contents at the soil aggregate level. A 5-year field study was carried out to analyze the impacts of the native grasses practice on the accumulation of soil organic carbon and nitrogen and the physicochemical properties and microbial communities of soil aggregates in navel orange orchards. Three treatments were tested: (i) clean tillage (CK); (ii) intercropping <i>Centella asiatica</i> (L.) Urban (CA); (iii) intercropping <i>Stellaria media</i> (L.) Cvr. (SM). Our work found that, compared to CK, the soil physical properties improved under the long-term management of native grasses, and the content of nutrients in the soil increased. The contents of SOC (+118.3–184.2%) and total nitrogen (TN) (+73.3–81.5%) changed significantly. The proportion of soil macro-aggregates and the stability of soil aggregates increased, and the contents of SOC and TN in the soil aggregates increased. In addition, under the long-term management of native grasses, the community diversity of beneficial microbes and the abundance of functional genes related to nitrogen cycling increased significantly in the soil aggregates. Native grasses increased the content of nutrients in the soil aggregates by increasing aggregate stability and the abundance of related microorganisms, altering the microbial community structure, and increasing the abundance of related genes for nutrient cycling, thereby enhancing the sequestration of SOC and TN in topsoil. Our results will provide a theoretical basis for the carbon enhancement and fertilization of native grasses as green manure in navel orange orchards and their popularization and application. |
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| ISSN: | 2311-7524 |