中国农业科学 ›› 2017, Vol. 50 ›› Issue (7): 1252-1262.doi: 10.3864/j.issn.0578-1752.2017.07.008

• 土壤肥料·节水灌溉·农业生态环境 • 上一篇    下一篇

东北黑土区旱田改稻田后土壤有机碳、全氮的变化特征

贾树海,张佳楠,张玉玲,党秀丽,范庆锋,王展,虞娜,邹洪涛,张玉龙   

  1. 沈阳农业大学土地与环境学院/农业部东北耕地保育重点实验室,沈阳 110866
  • 收稿日期:2016-08-29 出版日期:2017-04-01 发布日期:2017-04-01
  • 通讯作者: 张玉玲,E-mail:yuling_zhang@163.com;张玉龙,E-mail:ylzsau@163.com
  • 作者简介:贾树海,E-mail:jiashh024@163.com。
  • 基金资助:
    国家自然科学基金面上项目(41571280)、国家自然科学基金青年基金项目(41101276)

Changes of the Characteristics of Soil Organic Carbon and Total Nitrogen After Conversation from Upland to Paddy Field in Black Soil Region of Northeast China

JIA ShuHai, ZHANG JiaNan, ZHANG YuLing, DANG XiuLi, FAN QingFeng, WANG Zhan, YU Na, ZOU HongTao, ZHANG YuLong   

  1. College of Land and Environment, Shenyang Agricultural University/Key Laboratory of Northeast Arable Land Conservation, Ministry of Agriculture, Shenyang 110866
  • Received:2016-08-29 Online:2017-04-01 Published:2017-04-01

摘要: 【目的】分析东北黑土区旱田改稻田后土壤有机碳、全氮含量及其密度和13C、15N自然丰度值的动态变化,探讨旱田改稻田后土壤有机碳(氮)的固定能力及其稳定性,揭示旱田改稻田后土壤有机碳(氮)的演变规律,为东北黑土的合理利用和培肥提供理论依据。【方法】结合野外实地调查,选择典型黑土区旱田土壤(种植大豆年限大于60年)和改种不同年限的稻田土壤(3、5、10、17、20和25年,旱田改稻田前种植历史基本相同,均为大豆),利用稳定同位素分析技术,研究旱田改稻田后土壤有机碳、全氮的动态变化特征。【结果】旱田改稻田25年间,在0—60 cm土层,土壤有机碳和全氮含量的变化趋势均表现为:在改种的前3年迅速下降,降幅分别为13.60%—43.27%和10.40%—40.60%,在3—25年间随改种年限延长呈逐渐增加的趋势,且在20—60 cm土层出现累积,但在3—5年期间增加幅度较大,在5—25年期间增加较为缓慢,在改种17—25年期间,稻田土壤有机碳和全氮含量均高于旱田土壤;0—60 cm土层土壤有机碳和全氮密度的变化趋势与其含量的变化趋势大致相同,在改种的3年间0—60 cm土层土壤有机碳和全氮密度分别降低了26.53%和21.89%,在改种5—25年间0—60 cm土层稻田土壤有机碳和全氮密度均大于旱田土壤,增幅分别为9.87%—21.48%和10.2%—19.3%;旱田改稻田后,土壤全氮与有机碳的变化密切相关,土壤全氮与有机碳的含量、密度之间均呈显著线性正相关关系(P<0.01)。在0—60 cm土层,土壤δ13C值在改种的3年间明显上升,在3—25年间随改种年限延长呈逐渐下降趋势,且大于5年的稻田土壤δ13C值均低于旱田土壤,而土壤δ15N值在改种的25年间随改种年限延长呈逐年下降趋势,各年限稻田土壤δ15N值均低于旱田土壤,相同年限土壤的δ13C值和δ15N值均随着土层加深而增大;0—40 cm土层土壤δ13C值与土壤有机碳含量之间呈显著线性负相关关系(P<0.01),但各土层土壤δ15N值与土壤全氮含量之间则无显著相关性。【结论】东北黑土区旱田改稻田大于5年后,稻田土壤具有明显的固碳(氮)能力,稳定性碳(氮)在20—60 cm土层累积;改种稻田年限小于5年,应注重有机碳(氮)的补充,以维持和提高土壤有机碳(氮)水平。

关键词: 黑土;旱田改稻田;土壤有机碳;土壤全氮;&delta, 13C自然丰度值;&delta, 15N自然丰度值

Abstract: 【Objective】The aims of this article were to analyze the dynamic changes in the contents of soil organic carbon and total nitrogen and their densities, and in the values of 13C and 15N natural abundance, explore the sequestration and stability of soil organic carbon and total nitrogen, and to reveal the evolving rule of soil organic carbon (nitrogen) after conversation from upland to paddy field in black soil region of northeast China. The results would provide a theoretical basis for the reasonable utilization and fertilization in black soil. 【Method】 Combined with field investigation, the upland field (soybean planted for over 60 years) and paddy field with different years (3, 5, 10, 17, 20 and 25 a, soybean was planted in all the fields before their conversation to paddy field) were chosen as research objectives, and stable isotope analysis technology was employed to study the changes of the characteristics of soil organic carbon and total nitrogen after conversation from upland to paddy field. 【Result】 In 25 years of conversation from upland to paddy field, the changes of soil organic carbon and total nitrogen contents in the 0-60 cm soil layers showed the similar change trends of rapid drop in the first 3 years, the soil organic carbon and total nitrogen contents were decreased by 13.60%-43.27% and 10.40%-40.60%, then gradually increased with the extension of plant years between 3 to 25 years of conversation, and showed accumulation in the 20-60 cm soil layers, but increased faster between 3 to 5 years of conversation, increased slower between 5 to 25 years of conversation, between 17 to 25 years of conversation, the soil organic carbon and nitrogen contents in the paddy field all higher than in the upland field; the densities of soil organic carbon and total nitrogen in the 0-60 cm soil layers showed the similar change trends with their contents, they were decreased by 26.53% and 21.89% in the first 3 years, and their densities in the paddy field all higher than in the upland field between 5 to 25 years of conversation, they were increased by 9.87%-21.48% and 10.2%-19.3%. The close relationship was found between the changes of soil organic carbon and total nitrogen after conversation from upland to paddy field, also significant positive relationships were found between soil total nitrogen with organic carbon contents and it density (P<0.01), soil 13C natural abundance value in the 0-60 cm soil layers was significantly increased in the first 3 years, and dropped gradually between 3 to 25 years of the conversation. And soil 13C natural abundance value was lower in the paddy filed for more than 5 years than in the upland field. Soil 15N natural abundance value declined gradually with time during the conversation for 25 years, and it was lower in the paddy field than in the upland field in every year. Soil 13C and 15N natural abundance values increased with soil depth in the same years. It was found a significant negative relationship between soil 13C natural abundance value and soil organic carbon contents in the 0-40 cm soil layers (P<0.01), but there was no significant relationship between 15N natural abundance values and total nitrogen contents. 【Conclusion】 After conversation from upland to paddy field for more than 5 years, paddy field showed stronger ability of carbon (nitrogen) sequestration and accumulation of stable carbon (nitrogen) in the 20-60 cm soil layers. After the conversation less than 5 years, more attention should be paid to supplementation of organic carbon and nitrogen for soil in order to maintain and promote the level of soil carbon and nitrogen.

Key words: black soil, conversation from upland to paddy field, soil organic carbon, soil total nitrogen, 13C natural abundance value, 15N natural abundance value