摘要
以江苏省宿迁市潮土为供试土壤,设置DOC220、DOC440和DOC880 3个添加水溶性有机质(DOM)处理,分别含有机碳(DOC)220、440和880 mg.L-1。试验结果表明,DOM对硝化过程有一定的抑制作用,在培养第16天时,未添加DOM的对照中NH4+-N几乎100%已经转化为NO3--N,而添加DOM的3个处理硝化率分别比对照降低7.83%、13.60%和19.12%;与对照相比,添加DOM的处理中NH4+-N含量降低缓慢,但培养过程中亚硝酸盐的积累显著增加,对照在第12天时NO2--N达到最大积累量67.83 mg.L-1,而DOC220、DOC440和DOC880处理土壤中NO2--N积累量分别在第12、14和16天达到最大值,与对照相比积累量分别增加21.17%、33.91%和59.90%。此外,DOM的添加也降低了NO3--N的生成速率,到第16天时,对照已经达到最大积累量143.61 mg.L-1NO3--N,但此时DOC220、DOC440和DOC880处理中NO3--N含量比对照分别低41.97、78.09和91.30 mg.L-1。为排除因添加DOM带来外源氮所引起的影响,同时进行了相同初始氮量下添加DOM与单施(NH4)2SO4对硝化作用影响的比较试验,结果同样表现出亚硝酸盐积累量的增加和NO3--N生成速率的降低,表明DOM中所含的有机碳及小分子化合物影响了硝化作用。高有机质环境下存在潜在的亚硝酸盐积累风险,对土壤和水体生态系统健康可能有一定影响。
Effect of addition of dissolved organic matter （DOM） on nitrification in fluvo-aquic soil was studied. The soil used in the experiment was collected from Suqian, Jiangsu. The experiment had three treatments different in DOM addition rate ,220,440 and 880 mg·L^-1, respectively. Results show that addition of DOM inhibited nitrification to a certain extent. After 16 days of incubation,nearly 100% of NH4^＋-N in CK had changed into NO3^- -N. Compared with CK,the three treatments,DOC220,DOCA40 and DOC880, decreased by 7.83%, 13.60% and 19. 12%, respectively in nitrication, and hence the decrease in NH4^＋-N concentration in the treatments was much slower than in CK. The addition of DOM, however, increased nitrite accumulation significantly. In CK, NO2^- -N concentration peaked on D 12 in incubation, up to 67.83 mg·L^-1,whereas in Treatment DOC220,DOC440 and DOC880,it did on D 12,14 and 16, and 21.17% ,33.91% and 59.90% higher, respectively. The addition of DOM also decreased the production rate of NO3- -N. The maximum concentration of NO3^- -N, 143.61 mg·L^- 1, in CK was found on D 16, while only 41.97,78.09 and 91.30 mg· L^-1 in Treatment DOC220, DOCA40 and DOC880 respectively, much lower than in CK. In order to eliminate the effect of extraneous nitrogen brought in with the addition of DOM,comparison was made of effects of DOM addition and application of （NH4）2SO4 as the sole nitrogen source on nitrification in soils with same initial nitrogen concentration. Results also show increase in NO2^- -N accumulation and decrease in NO3^- -N production, which indicate that the organic carbon and low molecular organic compounds in DOM affected the process of nitrification. The findings of the experiment implied a high risk of NO2^- -N accumulation existed in environments high in organic matter content,which may have some bad effects on the health of the terrestrial and aquatic systems.
出处
《生态与农村环境学报》
CAS
CSCD
北大核心
2006年第3期45-50,共6页
Journal of Ecology and Rural Environment
基金
国家自然科学基金面上项目(40271098)
关键词
水溶性有机质
硝化作用
亚硝酸盐积累
dissolved organic matter
nitrification
nitrite accumulation
