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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。
In order to reveal the supply ability and potential of soil carbon and nitrogen in different types of straw mulching fields, the effects of corn stalks, tobacco stalks, rice stalks and rice straw biochar on soil organic carbon mineralization , Organic nitrogen mineralization and nitrification characteristics. The results showed that: after adding 1% different types of straw, the order of organic carbon mineralization rate and cumulative mineralization amount of the treated soil was corn straw> rice straw> tobacco straw> rice straw biochar> control; Compared with rice straw, biochar of rice straw reduced significantly the rate of organic carbon mineralization and the amount of mineralization. After adding different types of straw, the changes of organic nitrogen mineralization rate and nitrification rate were the same in all the treatments, all of them decreased with the increase of incubation time, and then slowly increased and then tended to balance. However, the nitrification rate and mineralization rate of different straw treatments in the early stage of culture showed a negative value, which may be related to the denitrification of soil and the immobilization of nitrogen by microorganisms. Therefore, in the process of straw returning with high carbon and nitrogen ratio, it is necessary to add exogenous nitrogen fertilizer to regulate the microorganisms to slow down the holding of nitrogen and promote the release of nutrients. And straw into biochar for returning to the field, can play a better carbon and nitrogen fixation effect.