摘要:为明确伴矿景天间作模式对辣椒植物根系周围土壤镉(Cd)迁移与可利用风险的影响, 于2019年在贵州省遵义市新蒲新区进行田间试验, 设置伴矿景天或辣椒单作、伴矿景天条带式间作辣椒(间作1)、伴矿景天交叉式间作辣椒(间作2)、伴矿景天混合式间作辣椒(间作3)等5种种植模式, 收获期采集辣椒根系周围土壤样品, 测定土壤各形态Cd含量和土壤pH、有机质、全量和有效氮磷钾以及球囊霉素(GRSP)含量。结果表明, 与辣椒单作相比, 间作2和间作3使辣椒根系周围土壤酸溶态Cd显著降低39.6%和41.5% (P<0.05), 可还原态Cd含量显著降低23.9%和29.0% (P<0.05)。同时也降低了土壤Cd迁移和植物可利用风险, 其中间作2和间作3处理土壤Cd迁移性分别降低25.8%和34.2%, 可利用性分别降低11.6%和26.9%。3种伴矿景天间作方式显著提高了土壤易提取球囊霉素含量, 分别提高24.5%、39.9%和40.6% (P<0.05); 间作2和间作3处理显著增加土壤总球囊霉素含量, 分别增加51.7%和86.7% (P<0.05)。冗余分析表明, 土壤环境因子对土壤Cd迁移和可利用风险影响重要性排序为总提取球囊霉素>速效钾>pH>易提取球囊霉素>全钾>全磷>全氮>碱解氮>有效磷>有机质, 土壤总提取球囊霉素、速效钾是影响土壤Cd迁移性和可利用性的关键调控因子。综上所述, 伴矿景天间作措施显著降低了辣椒根系周围土壤Cd迁移和可利用风险, 其中交叉式间作和混合式间作效果优于条带式间作。
关键词:间作/
辣椒/
伴矿景天/
镉/
迁移性/
可利用性
Abstract:A field experiment was conducted in Xinpu New District, Zunyi City, Guizhou Province, in 2019 to explore the effects of different Sedum plumbizincicola intercropping patterns on the migration and availability of cadmium (Cd) in the soil around the roots of Capsicum annum. Five planting patterns were established: monoculture S. plumbizincicola, monoculture C. annum, stripe intercropping of C. annum with S. plumbizincicola (JZ1), cross intercropping of C. annum with S. plumbizincicola (JZ2), and mixed intercropping of C. annum with S. plumbizincicola (JZ3). Soil samples were collected around the C. annum roots at harvest, and the Cd content, soil pH, organic matter content, and contents of total and available nitrogen (N), phosphorus (P), potassium (K), and content of glomalin (GRSP) were measured and analyzed. The results showed that, compared to C. annum monoculture, the contents of acid-soluble Cd and reducible Cd in the soil around the C. annum roots effectively decreased by 39.6% and 23.9% in the cross intercropping system with S. plumbizincicola, and 41.5% and 29.0% in mixed intercropping system with S. plumbizincicola, respectively. The risks of soil Cd migration and availability were also reduced. Stripe intercropping C. annum with S. plumbizincicola had no effect on Cd mobility and availability in the soil around the C. annum root system. The Cd migration of the crossing intercropping and mixed intercropping systems decreased by 25.8% and 34.2%, respectively, and the Cd availability decreased by 11.6% and 26.9%, respectively. The stripe, cross and mixed intercropping systems did not affect the contents of Cd in oxidizable and residual states, but significantly increased the content of easily extracted GRSP in the soil by 24.5%, 39.9%, and 40.6%, respectively. Cross intercropping C. annum with S. plumbizincicola and mixed intercropping treatments also significantly increased the total soil GRSP content by 51.7% and 86.7%, respectively. Redundancy analysis showed that the importance of the soil environmental factors on soil Cd migration and availability followed the order: total extracted GRSP > available potassium > pH > easily extractable GRSP > total potassium > total phosphorus > total nitrogen > alkaline hydrolyzed nitrogen > available phosphorus > organic matter. The extractable GRSP and available potassium from the soil were the key regulatory factors affecting soil Cd migration and availability. In summary, intercropping with S. plumbizincicola significantly reduced the risks of Cd migration and availability in the soil around the C. annum roots, and the effects of cross and mixed intercropping were better than that of stripe intercropping. These results provide a theoretical basis for better usage of farmland with low to medium levels of Cd.
Key words:Intercropping/
Capsicum annum/
Sedum plumbizincicola/
Cadmium/
Mobility/
Availability
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