With the aim of investigating the effects of biochar and nitrogen input on the season variation of carbon dioxide (CO2 ),methane (CH4 )fluxes,we measured CO2 and CH4 cumulative emission,CO2+CH4 emission intensity in dry farmland.A field experiment was performed over two years to measure CO2 and CH4 emissions by continuous observation using static chamber technique.Soil temperature and mois-ture were also measured at the same time.Three treatments were laid out with three replicates per experi-ment:C0 N0 (no biochar,no N),C0 N1 (no biochar,225 kg·hm-2 ),C1 N1 (50 t·hm-2 biochar,225 kg· hm-2 ).The results showed that:(1)the dry spring maize farmland was source for CO2 under three treat-ments during the experimental period.The rates of CO2 emission increased and peaked on the 22th June 2014 and the 1st July 2015 during the maize growing season.The rates then decreased and were maintained at a relatively low level during the fallow season.Biochar and nitrogen amendments decreased the CO2 flux and cumulative CO2 emission during the maize growing season.(2)The flux and cumulative CO2 emission were significantly lower in C1 N1 treatment than that in C0 N0 treatment during the two spring maize grow-ing seasons.(3)There was significantly positive correlation between CO2 flux and soil temperature.Both exponential equation and quadratic equation could be used to simulate the relationships,of which the corre-lation of 10 cm temperature was better than of 0 cm temperature.The CO2 flux had negative correlation with soil moisture.(4)The CH4 flux was between -16.08-73.96 μg·m-2 ·h-1 for all of the treat-ments, and was sink for CH4 .Biochar and nitrogen amendments increased the CH4 flux and cumulative CH4 emission during the maize growing season which were also affected by annual environmental factors. The CH4 emission had positive correction with soil moisture but negative with soil temperature.The addi-tion of biochar and nitrogen could reduce CO2 and increase CH4 fluxes and cumulative emission from dry farmland.Comprehensive consideration of two aspects,a reasonable addition of nitrogen and biochar would be beneficial for controlling greenhouse gas emission from dry farmland.Briefly,biochar and nitrogen amendment significantly increased the yield of maize,while reduced CO2+CH4 emissions intensity significantly.%为了研究生物炭与氮肥对旱作春玉米农田 CO2和 CH4排放通量季节变化、累积排放总量及 CO2+ CH4排放强度的影响,试验设置C0 N0(不加生物炭,不施氮肥)、C0 N1(不加生物炭,施氮肥225 kg·hm-2)和 C1 N1(添加生物炭50 t·hm-2,施氮肥225 kg·hm-2)3个处理,采用密闭式静态暗箱-气相色谱法对不同生物炭和氮肥输入旱作春玉米农田CO2和CH4排放通量进行连续观测,同时对影响通量变化的0~20 cm土层温度和水分因子进行测定。结果表明：(1)试验期内不同处理春玉米农田均表现为 CO2累积通量的源,且 CO2排放通量均呈现一定的峰值变化规律。(2)C1 N1处理减少了春玉米生长季农田CO2排放通量和累积排放总量,在试验的2个生长季内农田CO2平均排放通量和累积排放总量各处理均表现为C0 N0> C0 N1> C1 N1,且C1 N1处理降低显著。(3)土壤CO2排放通量与土壤温度变化呈显著正相关关系,可用指数方程和二次方程较好拟合二者关系,且与10 cm 土层温度的相关性优于0 cm土层温度,但土壤 CO2排放通量与土壤含水量呈负相关关系。(4)试验各处理农田土壤CH4排放通量在-16.08~-73.96μg·m-2·h-1之间,表现为大气CH4的净吸收库；C1 N1处理增加了土壤CH4排放通量和累积排放总量,但作用效果的显著性受年际环境因子的影响；农田土壤 CH4排放通量与土壤含水量呈显著正相关关系,与土壤温度呈显著负相关关系。研究发现,添加生物炭和施氮减少了旱作农田春玉米生长季CO2排放通量和累积排放总量,增加了CH4排放通量和累积排放总量,总体上显著增加了春玉米产量,显著减少农田CO2+CH4排放强度。
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