外源有机碳对黑土有机碳及颗粒有机碳的影响

为了阐释外源有机碳在土壤有机碳运转中的作用机制,以黑土为供试材料,进行了5年的室外培养试验,并结合室内全土及颗粒组分单独矿化培养试验,研究了不同外源有机碳对黑土有机碳(SOC)、颗粒有机碳(POC)含量及其矿化特征的影响。试验包括单施化肥、牛粪配施化肥、鸡粪配施化肥、秸秆配施化肥和树叶配施化肥5个处理。结果表明:(1)单施化肥黑土SOC的损失主要来源于POC的损失,外源有机碳有利于SOC和POC的累积,与对照相比,禽畜粪便处理的SOC和POC平均增加幅度分别为16.6%和27.8%,植物残体处理的SOC和POC平均增加幅度分别为27.0%和46.4%;(2)一级动力学方程能较好地描述SOC和POC的矿化动态(R~20.9),且POC比SOC易矿化,POC的60d累积矿化量是SOC的3倍以上;(3)禽畜粪便处理和植物残体处理的POC平均矿化率分别为31.5%和29.8%,禽畜粪便处理的POC更易矿化;(4)外源有机碳有效降低了黑土有机碳的矿化,尤其是牛粪,其SOC矿化率为1.9%,比对照低了3.4%,其POC矿化率为24.8%,比对照低17.4%;(5)外源有机碳在黑土中的碳累积能力表现为树叶秸秆牛粪鸡粪。

Effect of Exogenous Organic Carbon on Soil Organic Carbon and Particulate Organic Carbon in Black Soil

To definite the mechanism of the effects of exogenous organic carbon on soil organic carbon transport,we studied effect of exogenous organic carbon on concentrations and mineralization characteristics of soil organic carbon (SOC) and particular organic carbon (POC).We conducted a 5-year outdoor culture combined with the mineralization culture to analyze the translocation.There were 5 treatments:single chemical fertilizer,cow manure combined chemical fertilizer,chicken manure combined chemical fertilizer,corn stalks combined chemical fertilizer and poplar leaves combined chemical fertilizer.The results showed that:(1) SOC loss amount of the control in black soil mainly came from POC loss.The exogenous organic carbon was conducive to the accumulation of SOC and POC.Compared with the control,the average SOC and POC of animal manure treatments increased 16.6％ and 27.8％ respectively;plant residues treatments increased 27.0％ and 46.4％ respectively;(2) The dynamics of both SOC and POC mineralization preferably followed the first-order kinetics (R2＞ 0.9).POC was more easily mineralized than SOC.The 60 days cumulative mineralization amounts of POC were 3 times higher than SOC;(3) The average POC mineralization rate of the treatments added animal manure or plant residues was 31.5％ and 29.8％ respectively.POC of animal manure treatment was easier to be mineralized.(4) The mineralization of black soil organic matter can be retarded by the addition of exogenous organic matter,especially the cow manure.The SOC mineralization rate of the cow manure treatment was 1.9％,3.4％ lower than the control.The POC mineralization rate was 24.8％,17.4％ lower than the control;(5) The ability of storage carbon of exogenous organic carbon in black soil followed the order of poplar leaves ＞ corn stalks ＞ cow manure ＞ chicken manure.