有机肥施用对盐渍土富里酸荧光特性的影响

为探讨有机肥长期培肥盐渍土后土壤富里酸(FA)结构组成及土壤环境的变化特征,对黑龙江西北部盐渍土壤连续5 a采取不同施肥处理,设置CK(对照)和TR1(处理1,施用有机肥8 000 kg/hm2)、TR2(处理2,施用有机肥4 000 kg/hm2及化肥N 80 kg/hm2、P₂O₅ 50 kg/hm2、K₂O 35 kg/hm2)、TR3(处理3,施用化肥N 160 kg/hm2、P₂O₅ 100 kg/hm2、K₂O 70 kg/hm2) 4个处理组,分析土壤中富里酸荧光光谱特征的变化情况. 结果表明:与CK比较,TR1、TR2处理可明显增加土壤中ρ(富里酸),增幅分别为98.24%、72.16%；二维荧光参数分析显示,各处理下富里酸腐殖化程度均表现为TR1>TR2>TR3>CK；三维荧光光谱区域积分比值分析结果进一步证实,TR1、TR2处理通过增加可见区类富里酸的荧光响应比值和减少紫外区类富里酸的荧光响应比值来提高富里酸的腐殖化程度. 根据三维荧光光谱结合平行因子分析结果,可将富里酸分为C1组分(生物可利用富里酸组分)、C2组分(陆生来源富里酸组分)及C3组分(类蛋白组分)；施用有机肥主要增加C1组分的比例,其次为增加C2组分的比例,说明施用有机肥可提高盐渍土供肥能力,对盐渍土生态环境改善具有积极作用. 传统荧光图谱解析手段结合统计分析结果显示,施用有机肥可明显提高盐渍土富里酸含量并增加其腐殖化程度. 

Effects of Organic Fertilizer Application on Fluorescence Characteristics of Fulvic Acid in Saline Soil

In order to understand the structural composition of fulvic acid (FA) in soil, and the change features of the soil environment after the organic fertilizer-based fertility of saline soil, different fertilization treatments (CK (control), TR1 (application of organic fertilizer (8000 kg/hm2)), TR2 (application of organic fertilizer (4000 kg/hm2)+Fertilizer N (80 kg/hm2), P₂O₅ (50 kg/hm2), K₂O (35 kg/hm2)), TR3 (application of Fertilizer N (160 kg/hm2)), P₂O₅ (100 kg/hm2), K₂O (70 kg/hm2))) were conducted on saline soil that was reclaimed for five years in Northwest Heilongjiang to analyze the changes in the fluorescence spectral characteristics of fulvic acid in the soil. The results showed that, compared with CK, TR1 and TR2 significantly enhanced fulvic acid (ρ) in the soil by 98.24% and 72.16% respectively. Two-dimensional fluorescent parameter analysis showed that the humification degree of fulvic acid involved in each treatment was TR1>TR2>TR3>CK. Excitation-emission matrix regional integration analysis further confirmed that TR1 and TR2 enhanced the humification degree of FA by increasing the ratio of fulvic-like fluorescence in the visible region and decreasing the ratio of fulvic-like fluorescence in the ultraviolet region. Based on excitation-emission matrix, coupled with the result of the parallel factor analysis, fulvic acid could be divided into bioavailable fulvic acid component (component C1), terrestrial source fulvic acid component (component C2) and albuminoid component (component C3). The application of organic fertilizer could mainly increase the bioavailable FA component, followed by terrestrial source FA component, showing that organic fertilizer can improve the fertilizer supply ability of saline soil and play a positive role in improving the ecological environment of saline soil. Traditional fluorescence spectrum analysis, coupled with the statistical analysis result, showed that the application of organic fertilizer could significantly improve fulvic acid contents of saline soil and increase the humification degree of fulvic acid.