有机无机肥配施对苹果园温室气体排放的影响

Greenhouse gas emissions from an apple orchard with the mixed application of organic and chemical fertilizers

为研究有机肥代替化肥对苹果园温室气体排放的影响,本研究基于12 a的长期定位试验,采用静态暗箱-气象色谱法监测了果园温室气体(CH4和N_(2)O)排放的动态变化。试验共设置4个处理:对照(CK)、有机肥(M)、化肥(NPK)、有机无机肥配施(MNPK)。结果表明:果园年生活周期内CH4以吸收为主;N_(2)O排放的高峰均出现在施肥后。各处理温室气体累积排放量差异显著(P<0.05),其中M处理的CH4累积吸收量最高,为9.95 kg·hm^(-2);MNPK处理的N_(2)O累积排放量显著高于NPK处理。相关性分析结果显示,土壤含水量、气温及硝态氮、铵态氮均为影响温室气体排放的因素。与NPK处理相比,MNPK处理可显著增加苹果产量,提高氮肥农学利用效率,增加CH4吸收量、N_(2)O排放量和N_(2)O排放系数,降低综合温室气体排放强度。MNPK处理与NPK处理下单位产量CH4的累积吸收量分别为0.04 kg·t^(-1)和0.06 kg·t^(-1),单位产量N_(2)O累积排放量分别为0.05 kg·t^(-1)和0.07 kg·t^(-1),两处理间差异不显著。研究表明,有机无机肥配施在保证产量的前提下更有利于苹果园的可持续发展。

The combination of organic and inorganic fertilizers plays a key role in reducing the use of chemical fertilizers and increasing soil fertility.However,the effect of organic fertilizers relative to those of chemical fertilizers on greenhouse gas emissions in apple orchards remains unclear.Hence,an experiment was conducted to explore the temporal change in greenhouse gas emissions using a static-chamber gas chromatography technique during a long-term experiment.Four treatments were applied as follows:no fertilizer(CK),organic fertilizer only(M),chemical fertilizer only(NPK),and organic fertilizer plus inorganic fertilizer(MNPK).The principal findings were that CH4 was mainly absorbed by the soil,and the peak of N_(2)O emission fluxes always appeared after fertilization.There were significant differences in the cumulative emissions of greenhouse gases among all treatments(P<0.05).The highest cumulative absorption of CH4 was observed in the M treatment(9.95 kg·hm^(-2)).Additionally,the cumulative N_(2)O emissions in MNPK were significantly higher than those in NPK.Correlation analysis results indicated that greenhouse gas emissions were primarily driven by soil water content,air temperature,nitrate nitrogen,and ammonium nitrogen.Yield,nitrogen agronomic efficiency,the absorption of CH4 and the emissions of N_(2)O,and the N_(2)O emission factor were significantly enhanced,whereas greenhouse gas intensity was decreased under the MNPK treatment compared to that of NPK treatment.However,there was a non-significant difference between MNPK treatment(0.04 kg·t^(-1))and NPK treatment(0.06 kg·t^(-1))in yield-scaled CH4 absorption.Moreover,yield-scaled N_(2)O emissions for MNPK treatment and NPK treatment were not significantly different and were 0.05 kg·t^(-1) and 0.07 kg·t^(-1),respectively.In summary,organic fertilizer combined with chemical fertilizer is conducive to the sustainable development of apple orchards while ensuring production.