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草业学报 ›› 2024, Vol. 33 ›› Issue (2): 80-92.DOI: 10.11686/cyxb2023124

• 研究论文 • 上一篇    下一篇

施磷对紫花苜蓿土壤呼吸速率及活性有机碳组分的影响

魏孔钦(), 赵俊威, 张前兵()   

  1. 石河子大学动物科技学院,新疆 石河子 832003
  • 收稿日期:2023-04-17 修回日期:2023-05-16 出版日期:2024-02-20 发布日期:2023-12-12
  • 通讯作者: 张前兵
  • 作者简介:E-mail: qbz102@163.com
    魏孔钦(1998-),男,甘肃榆中人,在读硕士。E-mail: 1609913844@qq.com
  • 基金资助:
    国家自然科学基金项目(31660693);国家现代农业产业技术体系资助

Effects of phosphorus application on soil respiration rate and active organic carbon components of alfalfa

Kong-qin WEI(), Jun-wei ZHAO, Qian-bing ZHANG()   

  1. College of Animal Science & Technology,Shihezi University,Shihezi 832003,China
  • Received:2023-04-17 Revised:2023-05-16 Online:2024-02-20 Published:2023-12-12
  • Contact: Qian-bing ZHANG

摘要:

探究施磷对紫花苜蓿土壤呼吸速率及活性有机碳组分含量的影响,明确不同施磷处理条件下苜蓿田土壤呼吸速率及土壤活性有机碳组分之间的关系,以期为人工草地土壤固碳和可持续发展提供数据支撑。本试验采用随机区组设计,设置0(P0)、50(P1)、100(P2)和150 kg·hm-2(P3)4种施磷水平,重复3次。研究不同施磷水平下紫花苜蓿0~60 cm土层的土壤有机碳(SOC)、微生物量碳(MBC)、溶解性有机碳(DOC)、颗粒有机碳(POC)、易氧化有机碳(EOC)含量、土壤温湿度及呼吸速率(RS)。结果表明,不同土层SOC、MBC、DOC、POC和EOC含量随施磷量增加而升高,在P3处理下达到最大,分别为15.77 g·kg-1、0.42 g·kg-1、0.34 g·kg-1、4.68 g·kg-1和2.06 g·kg-1,且显著大于P0处理(P<0.05)。SOC、MBC、DOC、POC及EOC在垂直分布上均以0~20 cm土层含量最高,分别占总含量的38.35%~41.58%、38.31%~39.49%、45.54%~46.65%、46.29%~47.35%和40.40%~44.17%。施磷处理使土壤RS提高了0.31%~14.90%,且刈割前后差异显著(P<0.05)。随施磷量增加,不同土层MBC、DOC、POC及EOC的敏感指数均呈上升趋势。施磷处理下0~30 cm土层微生物量碳敏感指数最高,30~60 cm土层易氧化有机碳敏感指数最高。建议用微生物量碳指示表层土壤有机碳的变化,而易氧化有机碳可指示深层土壤有机碳的变化。各活性有机碳组分有效率随施磷量增加变化规律不明显。结构方程结果表明,施磷可直接影响SOC含量,也可通过改变MBC、DOC、POC和EOC含量而间接影响SOC含量。综上,施磷提高了土壤RS,但持续磷输入整体增加了苜蓿田土层内SOC、MBC、DOC、POC和EOC含量,提高了固碳潜力及土壤质量,可为全球磷沉降背景下人工草地生态系统土壤有机碳动态变化及人工草地管理提供科学依据。

关键词: 磷, 苜蓿, 土壤呼吸, 土壤有机碳, 活性有机碳

Abstract:

This research aimed to investigate the effect of phosphorus application on soil respiration rate and active organic carbon content of alfalfa, and to clarify the relationship between soil respiration rate and soil active organic carbon fraction in alfalfa fields under different phosphorus application treatments. It was envisaged these data would support identification of practices to maximize soil carbon sequestration and sustainable development of artificial grassland. The experiment was laid out in a randomized group design with four levels of phosphorus application: 0 (P0), 50 (P1), 100 (P2) and 150 kg·hm-2 (P3), and replicated three times. Soil organic carbon (SOC), microbial carbon (MBC), dissolved organic carbon (DOC), particulate organic carbon (POC), easily oxidized organic carbon (EOC), soil temperature and humidity and respiration rate (RS) were studied in under the different levels of phosphorus application for soil horizons to 60 cm depth. It was found that, the contents of SOC, MBC, DOC, POC and EOC increased with increasing phosphorus application across the different soil depths, reaching a maximum of 15.77 g·kg -1, 0.42 g·kg -1, 0.34 g·kg -1, 4.68 g·kg -1 and 2.06 g·kg -1, respectively, under the P3 treatment. These values were significantly (P<0.05) higher than under the P0 treatment. Vertically, SOC, MBC, DOC, POC and EOC all had the highest distribution in the 0-20 cm soil layer, accounting for 38.35%-41.58%, 38.31%-39.49%, 45.54%-46.64%, 46.29%-47.35% and 40.40%-44.17%, respectively, of the total content. The phosphorus application treatments increased soil RS by 0.31%-14.90% and the difference was significant before and after mowing (P<0.05). The sensitivity indices for MBC, DOC, POC and EOC in each soil depth showed an increasing trend with increasing phosphorus application, and the MBC sensitivity index was higher than the DOC, POC and EOC sensitivity indices. The highest sensitivity index of microbial carbon was found in the 0-30 cm soil layer under phosphorus application, and the highest sensitivity index of easily oxidized organic carbon was found in the 30-60 cm soil layer. It is suggested that microbial carbon is an indicator of changes in surface soil organic carbon and oxidizable organic carbon is an indicator of changes in deep soil organic carbon. The efficiency of each reactive organic carbon component does not change significantly with increasing phosphorus application. The results of structural equation models indicate that phosphorus application can affect SOC content directly and also indirectly through changes in MBC, DOC, POC and EOC content. In conclusion, phosphorus application increased soil RS, but sustained phosphorus input increased the SOC, MBC, DOC, POC and EOC contents in the various soil horizons of the alfalfa field, improving carbon sequestration potential and soil quality. These results provide scientific evidence of the dynamic changes of soil organic carbon in sown grassland ecosystems and will enhance sown grassland management with respect to optimizing phosphorous fertilizer use.

Key words: phosphorus, alfalfa, soil respiration, soil organic carbon, active organic carbon