西北地区旱田耕层土壤N_2O排放特征的研究

Emission Characteristic in Field Soil of Northwest Region

以冬小麦田耕作层原状土为研究对象,观测了小麦不同生长期、同一生长期不同温度下,耕层土壤N2O的释放特征。实验表明:温度对0～5cm土壤N2O释放的影响未达显著性差异;对0～10cm、0～15cm、0～20cm土层土壤N2O释放影响差异显著,且当温度增加到30℃时,温度变化对土壤N2O释放过程的影响效应强于25℃、20℃、15℃时。耕层中,不同层次土壤N2O的排放规律不同,30℃时,N2O主要产生于5～20cm土层,且表观值以5～10cm贡献最大占43%;而25℃时,以10～20cm土层贡献率最大;而20℃、15℃时,0～5cm土层排放大于5～10cm、10～15cm、15～20cm。小麦生育期耕作层土壤N2O排放以孕穗期最大,且排放峰值提前,而小麦生长后期(开花期和成熟期),N2O排放出现低谷,且峰值推后,反应物以土壤氮为主。

The paper described observation of N 2 O emission characteristic under the various growth periods of wheat and v arious temperature in untouched soil of win ter wheat field.The experiment show ed:at soil depth of 0～5cm,temperatu re had no significant effects on N 2 O emission,but at soil depth of 0～10c m,0～15cm,0～20cm,temperature had s ignificant influence on N 2 O e-mission.In addition,when the temperature reached at 30℃,the influence of temperature on N 2 O emission was greater than that at temperature of 25℃,20℃,15℃respectively.The N 2 O emission rule differed at differen t depth of the soil layer.When at 30℃,N 2 O mainly came from the layer at depth o f 5～20cm,the outlook value reached a t peak at depth of 5～10cm,amounting f or43%.When at 25℃,N 2 O mainly came from the layer at depth o f 10～20cm,when at 20℃,and 15℃.The co ntribution of N 2 O from the layer at depth of 0～5cm was la rger than that from the layer at depth of 5～10cm,10～15cm,15～20cm,respectively.During the growth period,the N 2 O emission reached the maximum value during booting period,and the emiss ion peak value was advance date.At the later period of t he growth,the N 2 O emission was weak,and the peak valu e was delayed.