长江中游稻田种植模式对土壤有机碳及碳库管理指数的影响

Effects of paddy field cropping patterns on soil organic carbon and carbon pool management index in the middle reaches of the Yangtze River

  • 摘要: 为探讨稻田种植模式对土壤有机碳库的影响,优化种植制度,以长江中游地区种植面积较广的紫云英-早稻-晚稻种植模式(CRR)为对照,设置油菜-早稻-晚稻(RRR)、马铃薯-早稻-晚稻(PRR)、紫云英-早稻-甘薯||晚大豆(CRI)、油菜-早稻-甘薯||晚大豆(RRI)5种种植模式,通过测定土壤有机碳、活性有机碳及其组分的含量和作物产量,分析其对土壤有机碳、活性有机碳及其组分、碳库管理指数及经济效益的影响。结果表明:晚稻收获后,与CRR处理相比,CRI、RRI、RRR处理的土壤有机碳含量提高12.06%~21.01%(P < 0.05),CRI、RRI、PRR处理的活性有机碳和微生物量碳含量比对照处理分别提高16.80%~20.45%和38.24%~50.00%(P < 0.05),各处理的可溶性有机碳含量提高3.13%~15.64%(P>0.05),CRI、RRI处理能显著促进土壤总有机碳和微生物量碳含量的积累,PRR处理则有利于土壤活性有机碳含量的积累。PRR处理提高了土壤碳库活度和碳库活度指数,RRI、CRI处理提高了土壤碳库指数,且CRI、RRI、PRR处理的土壤碳库管理指数均显著高于对照17.30%~33.49%(P < 0.05)。与对照相比,PRR、CRI处理的经济效益分别提高12.05%和9.86%(P < 0.05)。作物产量与微生物量碳存在极显著正相关关系(P < 0.01),土壤碳库管理指数与活性有机碳相关系数最高,呈极显著正相关(P < 0.01)。综上所述,与对照相比,各种植模式均有利于增加作物产量并可引起土壤有机碳及其组分的变化,其中紫云英-早稻-甘薯||晚大豆和马铃薯-早稻-晚稻模式的综合效果较好,可以在长江中游地区推广应用。

     

    Abstract: To explore the effects of paddy field planting patterns on soil organic carbon pools and to optimize cropping systems, in this study, we examined five typical paddy field cropping patterns in the middle reaches of the Yangtze River, including Chinese milk vetch-early rice-late rice (CRR, control), rape-early rice-late rice (RRR), potato-early rice-late rice (PRR), Chinese milk vetch-early rice-sweet potato||late soybean (CRI), and rape-early rice-sweet potato||late soybean (RRI). Soil organic carbon, active organic carbon and its components, carbon pool management index, and economic benefits were analyzed by measuring the content of soil organic carbon, the active organic carbon components in the paddy fields, and the crops yields. The results showed that after late rice harvest, compared to CRR, the CRI, RRI, and RRR treatments increased the soil organic carbon content by 12.06%-21.01% (P < 0.05); the CRI, RRI, and PRR treatments increased the active organic carbon content and microbial biomass carbon content by 16.80%-20.45% and 38.24%-50.00% (P < 0.05), respectively; while CRR, RRI, RRR and PRR increased the dissolved organic carbon content by 3.13%-15.64% (P>0.05). The CRI and RRI treatments significantly promoted the accumulation of soil total organic carbon and microbial biomass carbon, while the PRR treatment promoted the accumulation of soil active organic carbon. Compared to CRR, PRR increased the soil carbon pool activity and carbon pool activity index; RRI and CRI increased the soil carbon pool index; and CRI, RRI, and PRR significantly increased the soil carbon pool management index by 17.30%-33.49% (P < 0.05). The economic benefits of PRR and CRI increased by 12.05% and 9.86%, respectively (P < 0.05). There was an extremely significant positive correlation between rice yield and microbial biomass carbon (P < 0.01), and the correlation coefficient between the soil carbon bank management index and active organic carbon was the highest, with a significant positive correlation (P < 0.01). In summary, each cropping pattern is beneficial for increasing crop yield and changing the content of soil organic carbon and its components. Among them, Chinese milk vetch-early rice-sweet potato||late soybean and potato-early rice-late rice have better comprehensive effects, which can be popularized and applied in the middle reaches of the Yangtze River.

     

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