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为进一步理解红壤旱地土壤中碳源与土壤氮养分之间的耦合作用机制,以华中地区典型红壤旱地土壤为研究对象,运用静态培养法,设置室内培养试验,研究了添加葡萄糖、乙酸、草酸3种碳源对红壤旱地土壤中氮素矿化及反硝化的影响.结果表明,在25℃好氧培养下,不同碳源的添加对土壤氮素转化的影响具有较大差异.具体表现为:与对照处理(CK)相比,添加葡萄糖在整个培养期间内显著地促进了土壤可溶性有机氮(DON)含量的减少(p<0.01),在培养第1 d,添加葡萄糖显著地促进了氧化亚氮(N_2O)的排放、硝态氮(NO_3~--N)含量的减少(p<0.01);添加乙酸也显著促进了上述过程(p<0.05),但促进作用没有葡萄糖强烈;而添加草酸对上述过程的促进不显著.30 d培养结束后,葡萄糖、乙酸、草酸3种处理的DON含量分别为14.84、19.46和23.47 mg·kg~(-1),比CK处理(24.20 mg·kg~(-1))分别减少了38.68%、19.59%、3.02%;葡萄糖、乙酸、草酸3种处理的NO_3~--N含量分别为8.77、13.89和20.42 mg·kg~(-1),比CK处理(17.23 mg·kg~(-1))分别减少了49.10%、19.38%和增加了18.51%.研究表明,碳源的可利用性是促进土壤氮素矿化和反硝化的关键因素.
In order to further understand the mechanism of the coupling between soil carbon sources and soil nitrogen in red soils, taking the red soils of typical red soils in central China as the research object, the static culture method was used to set up indoor culture experiments. The effects of adding glucose, acetic acid, oxalic acid 3 Effects of carbon sources on nitrogen mineralization and denitrification in upland red soilsThe results showed that the effects of different carbon sources on soil nitrogen transformation were quite different under aerobic conditions at 25 ℃, Compared with control treatment (CK), adding glucose significantly promoted the decrease of soil soluble organic nitrogen (DON) content (p <0.01) during the whole culture period. Adding glucose significantly promoted the oxidation of (P <0.01). The addition of acetic acid also significantly promoted the above process (p <0.05), but the promotion effect was not as strong as that of glucose. However, the addition of oxalic acid The promotion of the above process was not significant. After 30 days of culture, the DON contents of glucose, acetic acid and oxalic acid were 14.84, 19.46 and 23.47 mg · kg -1, respectively, which were higher than those of CK (24.20 mg · kg ~ (-1)) decreased by 38.68%, 19.59% and 3.02 respectively %. The contents of NO_3 ~ -N in glucose, acetic acid and oxalic acid were 8.77, 13.89 and 20.42 mg · kg -1, respectively, which were lower than CK (17.23 mg · kg -1) 49.10%, 19.38% and 18.51% respectively.Research shows that the availability of carbon source is the key factor to promote soil nitrogen mineralization and denitrification.