中文摘要：

为揭示不同类型秸秆还田后烟田土壤碳氮养分的供应能力及潜力,通过室内好氧培养试验,研究了玉米秸秆、烟草秸秆、水稻秸秆及水稻秸秆生物炭对烟田土壤有机碳矿化、有机氮矿化及硝化特征的影响。结果表明：添加1%的不同类型秸秆后,各处理土壤的有机碳矿化速率及其累积矿化量的排序为玉米秸秆≥水稻秸秆〉烟草秸秆〉水稻秸秆生物炭≥对照;添加等量的水稻秸秆生物炭与水稻秸秆相比,土壤的有机碳矿化速率及累积矿化量明显降低。添加不同类型秸秆后,各处理土壤的有机氮矿化速率和硝化速率变化规律一致,均随着培养时间的推进呈现先减少然后缓慢增加再趋于平衡的趋势。而培养前期不同秸秆处理土壤的硝化速率及矿化速率出现负值,这可能与土壤发生反硝化作用及微生物对氮素的固持作用有关。因此,在碳氮比较高的秸秆还田过程中,需要适当添加外源氮肥进行调节,以减缓微生物对氮素的固持作用并利于养分释放。而且秸秆转化为生物炭进行还田,可以起到较好的增碳固氮效果。

英文摘要：

In order to evaluate the supply capacities of carbon and nitrogen nutrients in tobacco fields by different types of straw and stalk returning, the influences of corn stalk, tobacco stalk, rice straw and rice straw biochar on the organic carbon and nitrogen mineralization and nitrification in soils of tobacco fields were studied via aerobic incubation in laboratory. The results showed that： after applying different straws and stalks at 1% by weight, the soil organic carbon mineralization rate and its cumulative mineralization were in the order of corn stalk≥ rice straw≥ tobacco stalk≥ rice straw biochar≥ the control（without stalk or straw returning）. At the same applying rate, the organic carbon mineralization rate and its cumulative mineralization in soils treatedwith rice straw biochar were significantly lower than those with rice straw. After applying the different straws and stalks, the organic nitrogen mineralization rate and nitrification rate in soils changed in similar trends, i.e.reducing first then slowly increasing and reaching a steady state. However, the nitrification rate and mineralization rate in soils treated with different straws were negative at the early incubation stage, which might be related to soil denitrification and nitrogen immobilization by soil microorganisms. Therefore, in the process of straw returning with high carbon/nitrogen ratio, proper exogenous nitrogen was needed to slow down the immobilization for facilitating soil nutrient release. Straw transformed into biochar, then returned in fields,which had better effects on carbon accumulation and nitrogen immobilization.