添加有机肥对滨海盐渍土壤溶解性有机碳特征的影响

【目的】研究添加有机肥对滨海盐渍土壤溶解性有机碳(DOC)的影响,探究土壤DOC的组分来源以及滨海盐渍土壤碳库的稳定性,为改良滨海盐渍土并发挥其碳汇效应提供依据。【方法】以江苏大丰滨海两种不同盐分的盐渍土壤为研究对象,利用紫外-可见光谱和三维荧光光谱结合平行因子分析法,分析添加牛粪有机肥后两种盐渍土壤中DOC含量及紫外-可见光谱、三维荧光光谱特征的动态变化。【结果】添加有机肥的土壤DOC含量显著增加,且有机肥的添加提高了土壤DOC的腐殖化程度,试验第15天和第60天时高盐土壤DOC的腐殖化程度更高,土壤中DOC主要来源于添加的有机肥。三维荧光光谱特征显示,添加有机肥后土壤DOC中类富里酸峰较为明显。平行因子分析法将土壤DOC分为4个荧光组分:C1为外源类短波类腐殖质组分(紫外光区为类富里酸、海洋类富里酸),C2为外源类腐殖质组分(紫外光区、可见光区均为类富里酸),C3为内源类蛋白质组分(类络氨酸、类色氨酸),C4为内源类蛋白质组分(类络氨酸),随时间的变化各组分的占比也表现出不同的情况。【结论】滨海两种盐渍土壤添加牛粪有机肥后,土壤中DOC的含量、类腐殖质组分占比及腐质化程度均显著提高,类络氨酸组分的占比显著降低(P<0.05)。添加有机肥有利于盐渍土壤中活性碳库的稳定,但由于影响DOC的因素众多,不同的盐渍土壤表现情况各异。

Effects of organic fertilizer addition on dissolved organic carbon in coastal saline soils

【Objective】To establish a theoretical basis to improve coastal saline soil and its carbon sink function,this study investigated the effects of organic fertilizer on the dissolved organic carbon(DOC)content and component sources in coastal saline soil,alongside the stability of the soil carbon pool.【Method】Two types of saline soil with differing salinities(i.e.,high and low salt content)in the Jiangsu coastal area,China,were selected to explore changes in soil DOC content and its ultraviolet-visible(UV-Vis)spectrum and three-dimensional(3 D)fluorescence spectrum by UV-Vis spectroscopy and 3 D fluorescence spectroscopy.This was carried out alongside parallel factor analysis following the addition of organic cow manure fertilizer.【Result】The results showed that the DOC content and degree of DOC humification for soils treated with organic cow manure fertilizer increased significantly(P<0.05),compared with the control treated with no organic cow manure fertilizer.The extent of DOC humification in the soil samples collected on days 15 and 60 following the addition of cow manure from the high-salt soil was obvious higher than its low-salt counterpart.The DOC in soil was mainly sourced from the addition of organic cow manure fertilizer;following this,the 3 D fluorescence spectrum showed that the DOC fulvic acid peak was clearer.The parallel factor analysis identified four fluorescence components in the soil DOC:(1)C1 was the exogenous short-wave humic-like component(including UV region fulvic-like acid and marine fulvic-like acid);(2)C2 was the exogenous humic-like component(including UV region fulvic-like acid and visible region fulvic-like acid);(3)C3 was the endogenous protein-like component(including tryosine-like acid and tryptophan-like acid);(4)C4 was the endogenous protein-like component(only tryptophan-like acid).The proportion of each component in the soil DOC varied with time.【Conclusion】This study demonstrated that the addition of organic cow manure fertilizer to coastal saline soil increased the degree of DOC humification and the proportion of humic-like components in soil,while it significantly reduced the proportion of ammonia-like components(P<0.05).This indicates that the organic cow manure fertilizer is conducive to the stability of the active carbon pool in saline soil.However,as many factors affect soil DOC,the effects of organic cow manure fertilizer on soil DOC may different in other areas.