不同施肥模式对热区晚稻水田CH_4和N_2O排放的影响

Effects of Different Fertilization Modes on Greenhouse Gas Emission Characteristics of Paddy Fields in Hot Areas

由于农田温室气体排放的原位观测主要集中于温带和亚热带地区,热带地区农田土壤温室气体的排放往往被忽视.研究不同施肥模式下海南稻田温室气体排放特征对于准确评估我国农田土壤CH_4和N_2O排放及制定相应的减排措施有重要意义.本研究设置5个处理:空白对照(CK)、常规施肥(CON)、优化施肥(YH)、优化施肥与缓控释肥配施(ZYH1)、优化施肥、缓控释肥和有机肥三者配施(ZYH2),采用静态箱-气相色谱法,通过田间小区试验研究晚稻生长季CH_4和N_2O排放动态特征,并估算全球增温潜势(GWP)以及温室气体排放强度(GHGI).结果表明,CK、CON、YH、ZYH1和ZYH2处理的CH_4晚稻生长季累计排放量分别为175. 70、60. 30、63. 00、62. 80和56. 60 kg·hm^(-2),相应处理的N2O晚稻生长季累积排放量分别为0. 78、3. 40、1. 03、1. 44和0. 44 kg·hm^(-2). ZYH2的产量较CK、CON、YH和ZYH1分别提高了29. 69%、11. 81%、6. 74%和10. 36%,GWP较CK、CON、YH和ZYH1分别降低了64. 80%、43. 23%、12. 93%和15. 15%,同时,GHGI分别降低了76. 49%、52. 52%、20. 54%和23. 87%.相关分析结果表明:土壤温度和Eh是驱动CH_4排放变化的主要因素.综合产量及温室气体减排效果而言,优化施肥+羊粪有机肥+缓控释肥处理(ZYH2)是当地值得推广的减肥模式.

Greenhouse gas emissions studies commonly focus on temperate and subtropical regions.As a result,greenhouse gas emissions from agricultural soils in tropical areas are often neglected.Therefore,greenhouse gas fluxes in a Hainan paddy field under different fertilization regimes were studied.This research provides an accurate assessment of CH4 and N2 O emissions from paddy fields in China and sound mitigation measures.Through static chamber/gas chromatography techniques,CH4 and N2 O emissions,global warming potential(GWP),and greenhouse gas emissions intensity(GHGI)in late rice season under five fertilizer treatments were measured.The treatments included:control(CK),conventional treatment(CON),optimized fertilization treatment(YH),optimized fertilization combined with controlled slow-release fertilizer treatment(ZHY1),optimized fertilization combined with controlled slowrelease fertilizer and organic fertilizer treatment(ZHY2).The results showed that the cumulative CH4 emissions in the CK,CON,YH1,ZYH1,and ZYH2 treatments were 175.70,60.30,63.00,62.80,and 56.60 kg·hm-2,and the cumulative N2 O emissions were 0.78,3.40,1.03,1.44,and 0.44 kg·hm-2,respectively.Correlation analysis showed that soil temperature and Eh were the main factors driving CH4 emission.Compared with CK,CON,YH,and ZYH1,the yield of rice in ZYH2 treatment increased by29.69%,11.81%,6.74%,and 10.36%,respectively.While GWP of ZYH2 decreased by 64.80%,43.23%,12.93%,and15.15%,and GHGI decreased by 76.49%,52.52%,20.54%,and 23.87%,respectively.Therefore,in terms of yield and greenhouse gas emissions,optimal fertilization combined with sheep manure and slow release fertilizer treatment(ZYH2)is feasible in this region.