外加营养物对干旱区土壤硫交换通量的影响

Effects of Additive Nutrients on the Exchange Fluxes of Volatile Sulfur in Paddy Field Soil in Arid Area

应用静态箱式采样法,利用热解析仪与气相色谱联用的方法进行定量分析,研究不同营养添加物对干旱区水稻田土壤挥发性有机硫化物(VOSCs)地-气交换通量的影响。结果显示:在稻田土壤中施入不同的营养添加物后,除硫酸钠外,其余添加物质均可以促进VOSCs的释放;作为有机硫源,甲硫氨酸和半胱氨酸的添加明显地提高了土壤VOSCs的释放通量,表明含硫氨基酸是VOSCs的有效前体,淹水稻田土中的微生物通过分解作用释放VOSCs,释放的气体除了有大量的COS(羰基硫)和CS_2(二硫化碳)外,还有少量的DMS(二甲基硫)、CH_3SH(甲硫醇)以及DMDS(二甲基二硫);作为氮、硫源,硝酸铵和硫酸铵均可促进VOSCs的释放,但硫酸铵的作用时间相对较长,这主要归因于氮源和硫源的共同作用;碳源也能少量地促进VOSCs的释放。另外,培养条件(如温度等)对VOSCs的地-气交换通量也有一定的影响。

In this paper,the effects of different additive nutrients on the soil-air exchange fluxes of volatile organic sulfur compounds（ VOSCs） were studied. After collected by static chamber enclosure,the samples were determined by gas chromatography coupled with preconcentration and thermal desorption. The results showed that,except for sodium sulfate,the others of added materials could promote the release of VOSCs after adding different nutrients in paddy soil in arid area. As the organic sulfur nutrients,methionine and cysteine increased obviously the emission of VOSCs. As for the sorts of released gases,there were a large amount of COS（ carbonyl sulfide） and CS2（ carbon disulfide）,and a small quantity of DMS（ dimethyl sulfide）,CH3SH（ methyl mercaptan） and DMDS（ dimethyl disulfide）. These results showed that methionine and cysteine were the effective precursors of VOSCs.The microbial decomposition of sulfur-containing amino acids in waterlogged paddy soil could act as one source of biogenic sulfur gas emission. Both ammonium nitrate and ammonium sulfate could enhance the emission of VOSCs,but the latter caused the release time longer comparatively. This was mainly due to the combined effect of sulfur and nitrogen additions. The added carbon also caused an increase in the soil-air exchange fluxes. In addition,the culture conditions,such as temperature,had also the significant effects on the soil-air exchange fluxes of VOSCs.