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采用静态箱—气相色谱法对保护性耕作和常规耕作小麦田的N_2O排放进行了原位测量,测量了土壤温度、水分、无机氮等相关影响因子。结果表明:(1)保护性耕作及常规耕作麦田N_2O的排放具有明显的季节性变化规律,各处理变化趋势较为一致。(2)N_2O的平均排放通量和季节排放量,除免耕秸秆还田外,保护性耕作与常规耕作差异显著。(3)在小麦生长季内,保护性耕作农田均表现为N_2O的排放源。(4)各处理N_2O季节排放量大小顺序为:耙耕秸秆还田(1.64 kg/hm~2)>旋耕秸秆还田(1.59 kg/hm~2)>常规耕作秸秆还田(1.48 kg/hm~2)>深松秸秆还田(1.42 kg/hm~2)>常规耕作无秸秆还田(1.34 kg/hm~2)>免耕秸秆还田(1.33 kg/hm~2),即,与常规耕作相比,保护性耕作(除免还)N_2O排放量增加。(5)温度是制约N_2O排放的关键因素,随着温度的升高N_2O表现出增加的趋势。(6)N_2O排放与水分、土壤无机氮含量无相关性。
In situ measurements of N_2O emissions from conservation tillage and conventional tillage wheat fields were carried out using static box-gas chromatography (GC-MS), and related factors such as soil temperature, moisture and inorganic nitrogen were measured. The results showed that: (1) The seasonal variation of N 2 O emission in conservation tillage and conventional tillage fields was obvious, and the trend of the treatments was consistent. (2) The mean emission fluxes and seasonal emissions of N_2O, except tillage straw, have significant difference between conservation tillage and conventional tillage. (3) During the wheat growing season, all the conservation tillage farms showed N2O emission sources. (4) The sequence of seasonal emissions of N_2O in all treatments was as follows: (1. 64 kg / hm ~ 2)> straw returning to field (1.59 kg / hm ~ (1.42 kg / hm ~ 2)> conventional tillage without straw (1.34 kg / hm ~ 2)> no tillage with straw (1.33 kg / hm ~ 2) Conservation tillage (save for return) increases N_2O emissions compared with conventional tillage. (5) Temperature is the key factor that restricts the emission of N 2 O, N 2 O shows an increasing trend with the increase of temperature. (6) There is no correlation between N2O emission and water and soil inorganic nitrogen content.