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在室内培养条件下,以硝酸钙和碳酸氢铵为供试肥料,在45%、65%、100%田间持水量(Field Capacity-FC)条件下,研究了硝态氮肥和铵态氮肥在陕西关中塿土中对N2O释放的影响并区分了N2O产生的途径。结果表明,45%FC和65%FC条件下,施用铵态氮肥土壤的N2O释放量大于硝态氮肥,100%FC下反之。但当土壤湿度达到田间持水量时,由于硝化和反硝化作用都很强烈,两种肥料处理的N2O排放均达到最大值,分别为3.20,2.94mgkg-1。在10天培养期内,碳铵处理在各水分条件下释放的N2O总量接近,分别为2.05、2.03、2.94mgkg-1干土,而硝酸钙处理在各水分条件下释放的N2O总量分别为1.53、1.75、3.20mgkg-1干土。但通过硝化反硝化途径产生的N2O量对N2O总释放量的贡献差异较大。45%FC时,碳铵处理硝化和反硝化作用对N2O排放的贡献率分别为84.77%和15.23%;65%FC时分别为71.78%和28.22%;100%FC时的为48.50%和51.50%。由此可见,在本试验期内,硝化作用是土壤N2O排放的主要来源。硝酸钙在土壤中由于不存在硝化作用,所产生的N2O全部来自反硝化过程,在45%FC、65%FC和100%FC条件下,N2O释放量随含水量增加而增加,分别为1.53,1.75和3.20mgkg-1干土。
Under the condition of indoor cultivation, calcium nitrate and ammonium bicarbonate were used as tested fertilizers. Under the conditions of 45%, 65% and 100% field capacity (Field Capacity-FC), the effects of nitrate nitrogen fertilizer and ammonium nitrogen fertilizer in Shaanxi Influence of Guanzhonggeon on N2O Release and Distinguish the Way of N2O Production. The results showed that under the conditions of 45% FC and 65% FC, the N2O flux of ammonium nitrogen fertilizer was higher than that of nitrate nitrogen fertilizer, while 100% FC was the contrary. However, when the soil moisture reached the field capacity, nitrification and denitrification were both intense, and the N2O emissions of the two fertilizers reached the maximum values of 3.20 and 2.94 mg kg-1, respectively. During the 10-day incubation period, the total amount of N2O released by the ammonium bicarbonate treatment was close to 2.05, 2.03 and 2.94 mg kg-1 dry soil, respectively, while the total amount of N2O released by the calcium nitrate treatment under each water condition was 1.53, 1.75, 3.20 mg kg -1 dry earth. However, the contribution of N2O produced by the nitrification and denitrification process to the total N2O release varies greatly. 45% FC, the contributions of ammonium bicarbonate treatment and denitrification to N2O emissions were 84.77% and 15.23%, respectively, with 71.78% and 28.22% at 65% FC and 48.50% and 51.50% at 100% FC respectively. . Thus, nitrification was the main source of soil N2O emissions during the test period. Because of the absence of nitrification in the soil, all the N2O generated from calcium nitrate came from the denitrification process. The N2O emission increased with the increase of water content at 45% FC, 65% FC and 100% FC, which were 1.53, 1.75 and 3.20 mg kg -1 dry earth.