论文部分内容阅读
微生物对铵态氮(NH4+)和硝态氮(NO3-)具有不同的生物偏好性,两者电荷恰好相反致使两类离子具有各异的生物化学特征,两者间丰度的比例变化势必会影响土壤腐殖化的方向。论文以添加玉米秸秆的白浆土作为供试对象,通过添加相同氮素数量、不同形态氮素配比(NH4+∶NO3-为4∶1、NH4+∶NO3-为1∶1和NH4+∶NO3-为1∶4),试图揭示其对腐殖质组成变化的差异影响,结果表明:(1)无论外源氮素以何种形态为主,秸秆-白浆土混料中的微生物活性均可获得提升,其对混料中较易利用的水溶性有机碳(CWSS)、可提取腐殖酸(CHE)及胡敏酸(CHA)等组分皆可产生矿化分解作用,相比之下,铵硝等比例供应对CWSS及惰性的胡敏素组分(CHu)均可产生较为强烈的分解转化,在其驱动下,微生物对混料CHA的降解程度最高,使之结构趋于简单的程度最大,但CHA组分在此过程有“再合成”的可能;(2)受到硝态氮占优的供氮影响下,微生物可消耗混料CHE并使之降解片段进入CHu组分,不利于腐殖质活性的增加;(3)微生物利用外源以铵态氮为主的氮素形态更有利于其对CHA中较为简单有机分子片段的降解并使之向富里酸(CFA)转化,有利于腐殖质活性提升。
Microorganisms have different biological preferences for ammonium nitrogen (NH4 +) and nitrate nitrogen (NO3-). The exact opposite charge results in different biochemical characteristics for both types of ions. The ratio of abundance between the two is bound to be Affect the direction of soil humification. In this paper, albic soils with corn stalks were used as test objects. By adding the same amount of nitrogen, the ratio of different forms of nitrogen (NH4 +: NO3-: 4:1, NH4 +: NO3-: 1 and NH4 +: NO3- (1: 4). The results showed that: (1) The activity of microorganisms in straw-albicosol could be enhanced regardless of the forms of exogenous nitrogen , Which is able to produce mineralization and decomposition of more readily available components such as water-soluble organic carbon (CWSS), extractable humic acid (CHE) and humic acid (CHA) in the mixture. In contrast, ammonium The equal proportion of nitric oxide supplied to CWSS and inert humin component (CHu) all produced strong decomposition and transformation. Under the driving of microorganisms, the degree of degradation of mixed CHA was the highest, and the structure tended to be the simplest, (2) Under the influence of nitrogen supply, which is dominated by nitrate nitrogen, the microorganisms can consume the CHE of the mixture and degrade the fragments into the CHu component, which is unfavorable to the humus (3) The use of exogenous nitrogen-based nitrogen forms by microorganisms is more conducive to the use of more simple organic molecules in CHA Degradation segment and make it to the fulvic acid (CFA) transformation, help to enhance the activity of humus.