长期施肥对土壤有机质δ^(13)C值影响的初步研究

Preliminary Study of Impact of Long-term Fertilization on δ13C Values of Soil Organic Matter

以黑土、棕壤、草甸土和水稻土为供试土壤,通过田间定位并结合室内培养试验,初步研究了不同施肥(包括施用化肥、有机肥以及有机肥配施化肥)条件下全土有机质和胡敏酸的δ13C值。结果表明:一般与未施肥的处理相比,田间施用有机肥以及有机肥配施化肥使全土有机质和胡敏酸的δ13C值均呈下降趋势;培养试验中,施用猪粪后全土有机质和胡敏酸的δ13C值也呈下降趋势,而施用玉米秸秆后则呈增加趋势。产生上述结果的可能原因,一方面是由于不同有机肥料的δ13C值不同,另一方面则是由于施肥改变了土壤有机质的数量与结构组成。初步分析表明,施肥后全土有机质和胡敏酸的δ13C,值与其有机碳数量及结构组成之间并不存在显著的相关性,而全土有机质的δ13C值与其有机碳数量的增加量和增加率之间则存在显著的相关性。

Four long-term agricultural field experiments combined with an laboratory incubation experiment were conducted to evaluate the effect of organic, inorganic and organic＋inorganic fertilizer application on δ^13C value of soil organic matter （SOM） and humic acid （HA） in black soil, brown soil, meadow soil and paddy soil. Compared with unfertilized control plot, δ^13C value of SOM and HA decreased after the application of organic and organic＋inorganic fertilizer. And in the incubation experiment, δ^13C value of SOM and HA decreased after pig manure application, but increased after corn stalk application. There are two possible reasons for these results： the δ^13C value varied with different organic fertilizers, the amounts or structural compositions of SOM were changed by fertilization. Correlation analysis showed that there was no significant relationship between δ^13C value and organic carbon （ OC ） content or structural composition of SOM and HA, but the relationship was significant between δ^13C value and the increasing amount or rate of OC content of SOM.