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生物炭添加和灌溉是番茄地常用的田间管理措施,然而其对反硝化的影响还不清楚.本研究种植试验设置3个灌溉量水平分别为估算作物生育期需水量ET0的50%(W50%)、75%(W75%)、100%(W100%)和3个生物炭添加水平分别为B0(折合纯碳,0)、B25(折合纯碳,25 t·hm-2)、B50(折合纯碳,50 t·hm-2),在2014年和2015年番茄收获后,每个试验小区采集具有代表性的土样进行室内培养试验,采用乙炔抑制法来研究土壤的反硝化损失和不加乙炔研究N_2O的排放量.结果表明生物炭和灌溉量显著改变了土壤的理化性质.与B0相比,添加生物炭能够提高土壤全碳、全氮含量和pH值,降低铵态氮、硝态氮含量,而灌水量降低了土壤中全氮和全碳的含量.因此,与B0/W50%相比,B25/W75%和B50/W100%处理显著减少了反硝化损失量(P<0.05).生物炭和灌溉量的交互作用对土壤无机氮含量和反硝化损失的影响均达到显著水平(P<0.05),且对硝态氮的影响表现为灌溉量>生物炭添加量>两者交互作用,对铵态氮的影响表现为生物炭添加量>灌溉量>两者交互作用,对反硝化损失的影响表现为灌溉量>生物炭添加量>两者交互作用.反硝化损失量与土壤中无机氮含量、(CO_2-C)矿化量与N_2O排放量均呈正相关关系.不同生物炭添加量和灌溉量处理后明显影响了N_2O/DN(P<0.05),培养结束时,各处理下的N_2O累积排放量/DN累积排放量差异较大,介于0.31%~1.88%.
Biochar addition and irrigation are the commonly used field management measures in tomato field, however, their effects on denitrification are still unclear.In this study, three irrigation levels were set for estimating 50% of the water requirement ET0 during crop growth (W50% ), 75% (W75%), 100% (W100%) and three biochar were B0 (equivalent pure carbon, 0), B25 (equivalent pure carbon, 25 t · hm-2) Pure carbon, 50 t · hm-2). After the tomato was harvested in 2014 and 2015, each experimental plot collected representative soil samples for in-house culture experiments. The acetylene inhibition method was used to study the soil denitrification losses and not Acetylene was used to study the N 2 O emission.The results showed that biochar and irrigation significantly changed the physicochemical properties of soil.Compared with B0, adding biochar could increase soil total carbon, total nitrogen and pH value, reduce ammonium nitrogen and nitrate (P <0.05), while the irrigation amount reduced the contents of total nitrogen and total carbon in soils, so B25 / W75% and B50 / W100% treatments significantly reduced the amount of denitrification loss compared with B0 / W50% ) .The interaction of biochar and irrigation volume had significant effects on soil inorganic nitrogen content and denitrification loss (P <0.05), and The effect of nitrate nitrogen on the interaction between the amount of irrigation and the amount of biochar was interaction, and the effect on the amount of ammonium was as follows: the amount of biochar added> the amount of irrigated> interaction, and the effect on the denitrification was irrigated The amount of biochar added> the interaction between the two.The loss of denitrification and soil inorganic nitrogen content, (CO_2-C) mineralization and N_2O emissions were positively correlated.Under the different biochar dosage and the amount of irrigation N 2 O / DN (P <0.05). After the end of culture, the cumulative N 2 O / DN cumulative emissions varied greatly from 0.31% to 1.88%.