中国农业科学 ›› 2022, Vol. 55 ›› Issue (8): 1579-1588.doi: 10.3864/j.issn.0578-1752.2022.08.009

• 土壤肥料·节水灌溉·农业生态环境 • 上一篇    下一篇

东北黑土不同开垦年限稻田土壤有机氮矿化特征

高佳蕊(),方胜志,张玉玲(),安晶,虞娜,邹洪涛   

  1. 沈阳农业大学土地与环境学院/农业农村部东北耕地保育重点实验室,沈阳 110866
  • 收稿日期:2021-03-12 接受日期:2021-11-11 出版日期:2022-04-16 发布日期:2022-05-11
  • 联系方式: 高佳蕊,E-mail: 1203997865@qq.com。
  • 基金资助:
    国家自然科学基金面上项目(41571280)

Characteristics of Organic Nitrogen Mineralization in Paddy Soil with Different Reclamation Years in Black Soil of Northeast China

GAO JiaRui(),FANG ShengZhi,ZHANG YuLing(),AN Jing,YU Na,ZOU HongTao   

  1. College of Land and Environment, Shenyang Agricultural University/Key Laboratory of Northeast Arable Land Conservation, Ministry of Agriculture and Rural Affairs, Shenyang 110866
  • Received:2021-03-12 Accepted:2021-11-11 Published:2022-04-16 Online:2022-05-11

摘要:

【目的】分析东北黑土自然荒地开垦种稻后土壤矿化氮含量、氮净矿化速率和氮净矿化率,探讨土壤供氮能力及其特点,揭示土壤氮素的演变规律,为东北黑土的合理利用和培肥提供理论依据。【方法】以东北黑土自然荒地(0 a,为对照土壤,原始自然草甸植被)和不同开垦年限(12、35、62和85 a)的稻田(地形、种植制度、施肥和水分管理等大致相同)土壤为研究对象,采用长期淹水密闭-间歇淋洗培养方法,研究黑土自然荒地开垦种稻后土壤有机氮矿化的特征。【结果】在培养初期(约1个月),各年限土壤累积矿化氮量迅速增加,之后呈缓慢增加趋势;在淹水培养结束(297 d)时,土壤累积矿化氮量为212.43—388.11 mg·kg-1,各开垦年限土壤累积矿化氮量大小顺序为0、12、35、85和62 a。土壤有机氮矿化过程可用混合模型(Special 模型)很好地进行描述,并可将土壤有机氮库分为增量氮库和其他组分氮库,与对照土壤(0 a)相比,各年限稻田土壤增量氮库的氮矿化势(NF)均呈下降趋势,其中,开垦12 a与开垦35、62和85 a稻田土壤的NF 之间均无显著差异(P>0.05),但开垦12和35 a稻田土壤的NF显著高于开垦62和85 a稻田土壤(P<0.05),而矿化速率常数(kF)均呈上升趋势,但各年限田土壤的kF 之间均无显著差异(P>0.05);开垦12和35 a稻田土壤其他组分氮库的矿化速率常数(k0)无显著变化(P>0.05),但开垦62和85 a稻田土壤的k0则显著下降(P<0.05)。各年限土壤氮净矿化速率在培养4 d时为最大,之后逐渐下降,在淹水培养结束(297 d)时,土壤氮净矿化速率大小顺序与其累积矿化氮量的大小顺序相一致;各年限土壤氮净矿化率在淹水培养初期较高,之后缓慢增加,在培养结束(297 d)时,土壤氮净矿化率为78.60—101.82 mg·g-1,各开垦年限土壤氮净矿化率的大小顺序为0 a、35 a、12 a、85和62 a;土壤全氮和C/N是影响土壤矿化氮量和氮净矿化速率的重要因素(P<0.05)。土壤初始矿质氮与NF之和可用来表征当季稻田土壤供氮能力大小,与对照土壤(0 a)相比,各年限稻田土壤的供氮能力显著下降(P<0.05),开垦12和35 a稻田土壤的供氮能力显著高于开垦62和85 a的稻田土壤(P<0.05)。【结论】黑土自然荒地开垦种稻85 a间,稻田土壤的供氮能力均有所下降,种稻大于35 a时下降显著,因此在稻田土壤地力培育中应注重土壤有机质含量的提高。

关键词: 黑土区, 稻田土壤, 种稻年限, 矿化氮, 土壤供氮能力

Abstract:

【Objective】 The aim of this study was to analyze the mineralized nitrogen (N) content, net N mineralized rate and net N mineralized ratio (the ratio of mineralized N to total N) in paddy soil with different reclamation years in black soil, and to explore the soil N supply capacity and its characteristics, and to reveal the soil N evolution law, so as to provide the theoretical basis for rational utilization and fertilization of black soil in Northeast China.【Method】 The natural wasteland (0 years, as the control soil, original natural meadow vegetation) and paddy soils with different reclamation years (12, 35, 62 and 85 a) (topography and cropping system, fertilization, and water management, roughly the same) in black soil region were selected as the research object, and the characteristics of soil organic N mineralization after cultivated rice form natural wasteland in black soil were studied by the water-logged incubation method.【Result】 During the early stages of incubation (about 1 month), the cumulative mineralized N increased rapidly in each year, then showed a slow increase trend. At the end of incubation (297 d), the cumulative mineralized N ranged from 212.43 to 388.11 mg·kg-1, and the order of cumulative mineralized N was 0, 12, 35, 85 and 62 a. The mineralization process of soil organic N could be well described by a hybrid model (Special model), and the soil organic N pools could be divided into the increment N pool (the N pool made available after a drying and rewetting event) and the resistant N pool. Compared with the control soil (0 a), the potentially mineralisable N (NF) of the increment N pool in all paddy soils showed a decreasing trend in each year. There was no significant difference between paddy soils of 12 and 35 years, as well as 62 and 85 years, but the NF in paddy soils of 12 and 35 years were significantly higher than that of 62 and 85 years (P<0.05). The rate constant (kF) of mineralization of the increment N pool in paddy soils all showed an upward trend, but there was no significant difference between kF of all paddy soils in each year (P>0.05). Compared with the control soil (0 a), the rate constant (k0) of mineralization of the resistant N pool in paddy soils of 12 and 35 years did not change significantly (P>0.05), but k0 in 62 and 85 years decreased significantly (P<0.05). The net N mineralization rate of the soils in each year were the largest at 4 days of incubation, and then decreased gradually. At the end of water-logged incubation (297 d), the order of the soil net N mineralization rate was consistent with that of the cumulative mineralization N. The net N mineralized ratio was relatively high at the beginning of incubation, and then increased slowly. At the end of incubation (297 d), the net N mineralized ratio ranged from 78.60 to 101.82 mg·g-1, and the order was 0, 35, 12, 85 and 62 a. Soil total N and C/N were important factors affecting the amount of mineralization N and the net N mineralization rate in paddy soils with different reclamation years (P<0.05). The sum of initial mineral N and NF could be used to characterize the N supply capacity of paddy soil in rice growing season; compared with the control soil (0 a), the N supply capacity of paddy soil in each year decreased significantly (P<0.05), and the soils of 12 and 35 years were significantly higher than that of 62 and 85 years (P<0.05).【Conclusion】 During 85 years of rice cultivation from natural wasteland in black soil, the N supply capacity in paddy soil have declined, and the decline was significant after 35 years rice cultivation. Therefore, the improvement of soil organic matter content should be paid attention in the soil fertility cultivation in paddy fields.

Key words: black soil region, paddy soil, rice cultivation year, mineralizated nitrogen, soil nitrogen suppying capacity