长期不同施肥条件下红壤小麦和玉米季CO2、N2O排放特征

摘要

基于中国农业科学院红壤实验站红壤旱地小麦-玉米轮作长期定位试验,采用静态箱/气相色谱法,研究红壤旱地连续施肥16 a后,不同施肥条件下小麦季和玉米季土壤CO2和N2O的排放特征.结果表明,CO2和N2O排放具有明显的季节性,施肥对土壤CO2和N2O排放有明显影响,且有机肥的施用显著促进了土壤CO2和N2O排放.不施肥对照(CK)、氮磷配施(NP)、氮钾配施(NK)、氮磷钾配施(NPK)和有机无机肥配施(NPKM)处理小麦季和玉米季土壤CO2累积排放量分别为5 904、8 062、4 298、9 235、14 098和4 708、7 530、5 435、7 089、15 472 kg·hm-2,土壤N2O累积排放量分别为0.34、0.63、0.44、0.62、1.00和0.25、0.39、0.35、0.52、1.73 kg· hm-2,小麦休闲期土壤CO2和N2O累积排放量平均占小麦生长季的63.52％和28.43％,玉米休闲季平均占玉米生长季的49.98％和32.72％,说明休闲期土壤CO2和N2O累积排放量不容忽视.除玉米季NP、NK、NPK处理外,其他各处理小麦季和玉米季土壤CO2排放通量与5 cm深处土壤温度显著相关；而土壤N2O排放通量与土壤温度间均未表现出显著相关性；除NPKM处理外,其他各处理土壤CO2或N2O排放通量与土壤水分间相关性均未达显著水平.%Fluxes and cumulative emissions of CO2 and N2O from red soil during the wheat and corn seasons under different patterns of long-term fertilization (CK, NP, NK, NPK and NPKM) were monitored by making use of the long-term, 16-year wheat-corn rotation experiment on upland red soil in the Qiyang Red Soil Experiment Station, Chinese Academy of Agricultural Sciences. The static dark chamber method and gas chromatograph technique were used to collect and measure concentrations of CO2 and N2O. Results show that emissions of CO2 and N2O varied obviously with the seasons. Fertilization significant affected the emissions of CO2 and N2O, and application of manure significantly promoted the emission of CO2 and N20. The cumulative emission of CO2 from Treatment CK, NP, NK, NPK and NPKM was measured to he 5 904, 8 062, 4 298, 9 235 and 14 098 kg · hm -2 and 4 708, 7 530, 5 435, 7 089 and 15 472 kg· hm-2, respectively, in the wheat season and corn season, and the cumulative emission of N2O, 0. 34, 0. 63, 0. 44, 0. 62 and 1. 00 kg · hm~2 and 0. 25, 0. 39, 0. 35, 0. 52 and 1. 73 kg · hm ~2. On average, the cumulative emissions of CO2 and N2 O during the wheat fallow period accounted for 63. 52% and 28.43% , respectively, of the total of the whole wheat season, and the cumuJetive emissions of CO2 and N2O during the corn fallow period for 49. 98% and 32. 72% , respectively, of the total of the whole corn growth season, which suggest that emission of CO2 and N2O during the fallow season should not be neglected. Flux of CO2 emission in all the treatments was significantly related to soil temperature at 5 cm depth, except for Treatment NP, NK. And NPK in the corn season, but flux of N2O emission was not in any of the treatments. None of the treatments, except for Treatment NPKM, showed any significant relationship between flux of CO2 or N2O emission and soil water content.