中国农业科学 ›› 2007, Vol. 40 ›› Issue (3): 524-531 .

• 土壤肥料·节水灌溉 • 上一篇    下一篇

盆栽条件下红黄泥微生物量氮和固定态铵的动态变化

仇少君,彭佩钦,李 玲,刘 强,荣湘民   

  1. 中国科学院亚热带农业生态研究所亚热带农业生态重点试验室
  • 收稿日期:2006-07-12 修回日期:2006-11-05 出版日期:2007-03-10 发布日期:2007-03-10
  • 通讯作者: 彭佩钦

Dynamics of Soil Microbial Biomass Nitrogen and Fixed Ammonium in reddish clayey soil during Pot Experiment

  

  1. 中国科学院亚热带农业生态研究所亚热带农业生态重点试验室
  • Received:2006-07-12 Revised:2006-11-05 Online:2007-03-10 Published:2007-03-10

摘要: 【目的】研究盆栽条件下红黄泥微生物和晶格对有机、无机氮源的固定以及土壤微生物量氮(SMBN)和固定态铵的动态变化。【方法】采用15N示踪技术对有机无、机氮源交叉标记进行盆栽试验,设置单施尿素(15NU)、标记尿素与稻草配施(15NU-S)和标记稻草与尿素配施(15NS-U)3个处理。【结果】在水稻生育期内,SMBN和固定态铵占全氮比例分别为2.20%~4.00%和4.77%~ 8.37%;SMBN在孕穗期出现最低值,各处理固定态铵在分蘖期出现最低值。水稻成熟时,SMBN和固定态铵各处理间差异不显著。微生物和晶格固定的尿素氮分别为4.01~15.14 和0.47~4.82 mg•kg-1,占施用尿素氮的1.76%~8.83%和0.28%~2.11%;固定的秸秆氮分别为0.97~2.85和0.09~0.50 mg•kg-1,占施用秸秆氮的1.69%~4.98%和0.15%~0.87%。有机无机肥配施促进了微生物对尿素氮的固定,降低了晶格的固定。单施尿素处理和有机无机肥配施处理SMBN的最大释放率为66.04%和69.15%,固定态铵最大释放率为87.75%和87.64%。【结论】盆栽水稻条件下,土壤微生物和矿物晶格对外源氮的固定和释放是一个动态的过程,有机无机肥配施对SMBN和固定态铵有明显影响。

关键词: 土壤微生物量氮, 固定态铵, 盆栽, 红黄泥

Abstract: 【Objective】It was studied the immobilization of nitrogen by microbe and crystal cell in reddish clayey soil after amending urea and straw as well as the dynamics of soil microbial biomass nitrogen (SMBN) and fixed ammonium during the period of rice growth. 【Method】 A flooded pot experiment was conducted during the period of rice growth and composed of four treatments which were control group (CK), labeled urea group (15NU), the combined application of labeled urea and rice straw powder group (15NU-S) and the combined application of labeled rice straw power and urea group (15NS-U). 【Result】 During the period of rice growth, the percentage of SMBN and fixed ammonium to total nitrogen were 1.90% ~ 5.91% and 4.77% ~ 8.37%, respectively; SMBN was minimum at rice booting stage and fixed ammonium was minimum at rice tillering stage; For SMBN, there was no significant difference between fertilizers treatments at rice matured stage and the same to fixed ammonium. The immobilization of urea nitrogen by microbe and crystal cell were 4.01 ~ 15.14 mg·kg-1 and 0.47 ~ 4.82 mg·kg-1, respectively; and the percentage of labeled substrate SMBN and labeled substrate fixed ammonium to urea nitrogen were 1.76% ~ 8.83% and 0.28% ~ 2.11%, respectively. The immobilization of rice straw nitrogen by microbe and crystal cell were 0.97 ~ 2.85 mg·kg-1 and 0.09 ~ 0.50 mg·kg-1, respectively; and the percentage of labeled substrate SMBN and labeled substrate fixed ammonium to rice straw nitrogen were 1.69% ~ 4.98% and 0.15% ~ 0.87%, respectively. The combined application of urea and rice straw powder groups (CAURS, including 15NU-S and 15NS-U) increased the assimilation of microbe, decreased the immobilization of crystal cell. There was a significant negative relationship between SMBN and fixed ammonium. The maximum releasing rate of SMBN in 15NU and CAURS were 66.04% and 69.15%, respectively; those of fixed ammonium in 15NU and CAURS were 87.75% and 87.64%, respectively.【Conclusion】During the period of rice growth, the immobilization of labeled substrate nitrogen by microbe and crystal cell was a dynamic process. SMBN and fixed ammonium reached the minimum at the booting stage and the tillering stage, respectively. The CAURS increased the assimilation of chemical fertilizer by microbe and decreased the immobilization of chemical fertilizer by crystal cell.

Key words: Soil microbial biomass nitrogen, Fixed ammonium, Pot experiment, Reddish clayey soil