【摘要】 氮沉降是影响土壤有机碳矿化的重要因素,而不同形态氮素对有机碳矿化的影响仍不清楚。为探讨不同形态氮输入对湿地土壤有机碳矿化的影响,以黄河三角洲芦苇湿地为例,通过室内培养,研究硝态氮、铵态氮和有机氮输入对土壤有机碳矿化的影响。每种氮输入类型设置对照、低、中、高4个氮输入梯度。结果表明:(1)无机氮(硝态氮和铵态氮)输入抑制表层(0～20cm)土壤有机碳矿化(p<0.05),降幅为8.84%～25.63%,对中层(20～60cm)土壤有机碳矿化无显著影响;硝态氮输入促进下层(60～80cm)土壤有机碳矿化,增幅为23.24%～32.75%,对底层土壤(80～100cm)有机碳矿化无显著影响;铵态氮输入促进60～100cm深度土壤有机碳矿化,增幅为46.42%～109.7%。(2)有机氮输入抑制表层(0～20cm)土壤有机碳矿化(p<0.05),降幅为11.33%～25.93%;对20～40cm深度土壤有机碳矿化无显著作用,对其他土层土壤有机碳矿化主要为促进作用,增幅为26.77%～231.64%。综上,硝态氮、铵态氮输入对0～100cm深度土壤有机碳矿化无显著影响,而有机氮输入则促进0～100cm深度土壤有机碳矿化,且有机氮输入的促进作用大于无机氮(p<0.05)。因此,有机氮输入将显著削弱研究区芦苇湿地土壤有机碳库的稳定性。更多还原

【Abstract】 Nitrogen(N)deposition is an important factor influencing the decomposition of soil organic carbon(SOC).However,little information is known about the effect of N forms on SOC decomposition.The aim of this study is to distinguish the effects of organic and inorganic N additions on SOC decomposition.An incubation experiment is conducted and the soil samples are collected from the reed(Phragmites australis)wetlands in the Yellow River Delta.The level of N additions is set.The results show that,(1)nitrate and ammonium additions suppressed SOC decomposition by 8.84%～25.63%in the depth of 0～20 cm,and have no effect on SOC decomposition in the depth of 20～60 cm.Nitrate addition increased SOC decomposition by 23.24%～32.75%in the depth of 60～80 cm,and had no effect on SOC decomposition in the depth of 80～100 cm.Ammonium accelerated SOC decomposition by 46.42%～109.7%in the depth of 60～100 cm.And(2)organic N addition decreased SOC decomposition by11.33%～25.93%in the depth of 0～20 cm,and had no effect on SOC decomposition in the depth of20～40 cm,and increased SOC decomposition by 26.77%～231.64%in the depth of 40～100 cm.In general,nitrate and ammonium additions have no effect on SOC decomposition in the depth of 0～100 cm,and organic N addition accelerated SOC decomposition in the depth of 0～100 cm.Moreover,the positive effect of organic N addition on SOC decomposition is larger than that of inorganic N addition.Thus,organic N addition will reduce the stability of SOC pools in the reed wetlands of the Yellow River Delta.更多还原