中国农业科学 ›› 2014, Vol. 47 ›› Issue (4): 702-709.doi: 10.3864/j.issn.0578-1752.2014.04.010

• 土壤肥料·节水灌溉·农业生态环境 • 上一篇    下一篇

寒地稻田土壤氮素矿化特征的研究

 彭显龙1, 刘洋1, 于彩莲2, 王迪1   

  1. 1、东北农业大学资源与环境学院,哈尔滨 150030;
    2、哈尔滨理工大学化学与环境工程学院,哈尔滨 150040
  • 收稿日期:2013-06-14 出版日期:2014-02-15 发布日期:2013-12-18
  • 通讯作者: 彭显龙,Tel:0451-55191094;E-mail:pxl0508@163.com
  • 作者简介:彭显龙,Tel:0451-55191094;E-mail:pxl0508@163.com
  • 基金资助:

    国家自然基金项目(41101281)

Study on the Nitrogen Mineralization Characters of Paddy Soil in Cold Area

 PENG  Xian-Long-1, LIU  Yang-1, YU  Cai-Lian-2, WANG  Di-1   

  1. 1、Resources and Environmental Sciences College of Northeast Agricultural University, Harbin 150030;
    2、Institute of Chemical and Environmental Engineering, Harbin University of Science and Technology, Harbin 150040
  • Received:2013-06-14 Online:2014-02-15 Published:2013-12-18

摘要: 【目的】土壤供氮能力是影响稻田氮效率的主要指标之一,寒地稻田与南方稻田相比具有氮肥用量低和氮素利用效率高的特点,通过比较南北方稻田土壤供氮能力的差异,以期揭示土壤氮素矿化与寒地稻田氮素高效利用的关系。【方法】选择江苏省高肥力的乌栅土和中等肥力勤沙土,以及黑龙江三江平原高中肥力白浆土型水稻土,采用淹水密闭培养法,在25℃、30℃和40℃条件下恒温培养28 d,测定培养前后土壤铵态氮的含量,并分析土壤有机质、全氮和有机氮各组分的含量;通过一级动力学模型和有效积温模型拟合土壤氮素矿化与培养时间的关系。【结果】南方高中肥力土壤酸解氮、氨基酸态氮占土壤全氮比例均高于北方高中肥力土壤,北方稻田土壤碳氮比较高。在25℃培养28 d,南方和北方高肥力土壤间,以及中等肥力土壤间累积矿化氮量无明显差异。当温度为40℃时,南方高肥力和中等肥力土壤28 d累积矿化氮显著高于对应肥力的北方土壤。这与南方土壤有机氮含量或者有机氮所占比例较高有关。One-pool模型拟合显示,在25℃时北方土壤矿化势(N0)比对应肥力南方土壤增加了35.9%—36.3%;当温度为30℃和40℃时,北方土壤与南方对应肥力土壤相比N0降低了6.1%—32.7%和20.9%—36.7%。北方土壤微生物不耐高温,是其40℃矿化势较低的原因。有效积温模型拟合显示,随温度增加同一土壤氮矿化特征常数n值逐渐减小;南方土壤的氮矿化特征常数K值较高,而北方土壤n值高,表示南方中高肥力土壤的初期矿化速率高,而北方中高肥力土壤后期矿化速率高。【结论】土壤矿化氮含量和矿化势受土壤微生物活性、土壤碳氮比、土壤有机氮含量及其占全氮的比例影响,25℃下北方稻田土壤可矿化氮量较高,而且相对南方稻田土壤而言,寒地稻田土壤氮素矿化前期较慢,后期较快的特点与水稻吸氮更协调,这是寒地稻田氮素高效利用的原因之一。

关键词: 寒地 , 稻田 , 温度 , 氮素矿化 , 有机氮

Abstract: 【Objective】Compare to southern paddy fields, total applied nitrogen amount is lower and nitrogen use efficiency is higher in northeast of China. Soil N supply ability is closely related to nitrogen application and nitrogen efficiency. It is very important to compared nitrogen supply ability between southern and northern paddy soil. This would be helpful to reveal the relationship between soil nitrogen supply and high N efficiency in northern paddy.【Method】The tested soil was composed of gleyed paddy soil with high fertility and hydromorphic paddy soil with medium fertility from Jiangsu province, as well as albic paddy soil with high and medium fertility from Heilongjiang province. The samples were incubated at 25℃,30℃ and 40℃ for 28 days, respectively. Soil ammonium nitrogen was detected before and after incubation. At the same time, soil organic matter, total nitrogen and organic N forms were determined before incubation. Effective cumulated temperature model and One-pool model were fitted to the observed mineral-N vs incubation days using non-linear regression procedure. 【Result】 Ratios of the hydrolysamino acid N and amino acid N to total N were higher in southern paddy soil than the northern soil with corresponding fertility, however, the C/N in northern soil was higher. There was no significant difference of cumulative mineralization N on 28 days after incubation between southern and northern paddy soil under 25℃. When the incubation temperature was increased from 25℃ to 40℃, the cumulative mineralization N of southern soil with high fertility or medium fertility was higher than northern soil with corresponding fertility due to high organic nitrogen forms of soil or ratio of organic nitrogen forms to total nitrogen in southern soil. One-pool model between cumulative soil mineralization N and incubation days showed that soil N mineralization potential (N0) of northern soil increased by 35.9%-36.3% compared to southern soil with corresponding fertility under 25℃. On the contrary, N0 of northern soil decreased by 6.1%-32.7% and 20.9%-36.7% than southern soil with corresponding fertility under 30 ℃ and 40℃, respectively. Low soil microbial activity under high temperature may be the reason of lower N0 in northern soil. Effective cumulated temperature model between cumulative soil mineralization N and incubation days showed that the n value of same soil decreased with the increase of temperature. Southern soil had higher K value and Northern soil had higher n value. Therefore, earlier mineralization rate of southern soil was clearly higher than northern soil, but later N mineralization rate was lower. 【Conclusion】 The content of mineralized nitrogen and N0 depends on soil microbial activity, ratio of soil carbon to nitrogen, content of soil organic nitrogen and the proportion of organic form nitrogen to total nitrogen. Nitrogen mineralization potential of northern paddy soil was higher than southern soil under 25 ℃. Compared to southern paddy soil, the rate of nitrogen mineralization in northern soil was slower and faster in the early and late stage, respectively. This nitrogen mineralization character for northern paddy soil matched to rice N uptake, which was one of the reasons for high nitrogen use efficiency in cold area.

Key words: cold area , paddy soil , temperature , N mineralization , organic N forms