菌渣还田量对紫色水稻土净温室气体排放的影响

Effects of Mushroom Residue Application Rates on Net Greenhouse Gas Emissions in the Purple Paddy Soil

中国是食用菌生产大国,每年食用菌菌渣产出量较大,为探明菌渣还田量对紫色水稻土净温室气体排放的影响,于2017年3~9月,通过盆栽试验,采用静态暗箱/气相色谱法,研究了不施肥(CK)、常规施肥(NPK)、9 t·hm^(-2)菌渣+NPK(LM)、18 t·hm^(-2)菌渣+NPK(MM)、36 t·hm^(-2)菌渣+NPK(HM)这5种处理稻田土壤温室气体的排放规律,并采用土壤碳库法对农田系统净温室气体排放(NGHGE)进行评价.结果表明:(1)土壤温室气体(包括CH_4、CO_2、N_2O)排放随着菌渣还田量的增加而增加,CH_4排放量顺序为:HM>MM>LM≈NPK>CK;HM处理显著增加了CH_4的排放通量(P<0.01),其他处理差异并不显著(P>0.05),CH_4排放通量LM处理呈双峰型曲线,MM处理呈多峰型,HM处理呈现非常明显的单峰型曲线;CO_2累积排放量大小依次为:MM>NPK≈LM>HM>CK,CO_2排放通量曲线LM处理呈单峰型、MM处理呈双峰型、HM处理呈现多峰型;NPK处理N_2O累积排放量显著高于其他处理,N_2O排放通量曲线NPK处理呈双峰型、LM和MM处理呈现多峰型,HM呈单峰型变化;(2)LM处理土壤固碳能力较低,NPK、MM与HM处理土壤固碳能力均较高;MM处理土壤固碳能力显著高于其他处理(P<0.01),比纯施化肥处理提高了59.2%,比LM和HM处理提高了87.79%和65.65%;与土壤固碳能力相反,LM处理植物固碳能力最高,比NPK和MM处理提高了16.1%~22.2%,约为CK处理和HM处理的2.1倍;(3)MM处理整个水稻生产期NGHGE值最小,为-490.29 kg·hm^(-2),表现为温室气体的"汇",18 t·hm^(-2)菌渣还田是紫色水稻土净温室气体排放最优的还田方式.

China is the leading country for production of edible mushrooms and also outputs numerous mushroom residues.The recycling of mushroom residue can solve environmental pollution problems,provide nutrients for the farmland,and play an important role in reducing greenhouse gas emissions and increasing soil carbon sequestration capacity.In order to investigate the effects of mushroom residue amounts on net greenhouse gas emissions in purple paddy soil,potted experiments using static opaque chamber and gas chromatography methods were used to study the changes of greenhouse gases,soil carbon sequestration,and net greenhouse gas emissions（NGHGE） in the paddy soil with five treatments： no fertilizer（CK）,conventional fertilization（NPK）,9 t·hm（-2） mushroom residue ＋ NPK（LM）,18 t·hm（-2） mushroom residue ＋ NPK（MM）,and 36 t·hm2 mushroom residue ＋ NPK（HM） from March 2017 to September 2017.The results showed that：（1） The greenhouse gas emissions（including CH4,CO2,and N2O） increased with increasing additions of mushroom residue.The emissions of CH4 from highest to lowest followed： HM MM LM≈NPK CK.The HM treatment significantly increased the CH4 emission flux（P 〈 0.01） more than the other treatments and showed an obvious single peak curve,while the CH4 emission flux with the LM treatment showed a bimodal curve,and the MM treatment showed a multiple peak curve.The CO2 emission flux followed： MM 〉 NPK≈LM HM 〉 CK; and the curves for the LM,MM,and HM treatments were a single peak curve,bimodal curve,and multiple peak curve,respectively.The N2O cumulative emission from the NPK treatment was significantly higher than with the other treatments.The N2O emission flux of the NPK treatment was a bimodal curve and that of the HM treatment was a single peak curve,while the N2O emission flux of treatments LM and MM showed multiple peak curves.（2） The carbon sequestration capacity with the LM treatment was lower than that of the other treatments and that from the MM treatment was the highest.The carbon sequestration capacity of the MM treatment increased by 59.2% compared to that of the NPK treatment and increased by 87.79% and 65.65% compared to that of the LM and HM treatments.The LM treatment has the highest carbon sequestration capacity,which was higher than that of the NPK and MM treatments and about 2.1 times greater than the CK treatmentand HM treatment.（3） The minimum NGHGE value was-490.29 kg·hm（-2） for the whole rice production period,and 18 t·hm（-2） mushroom residue applied to the soil was the best way to reduce net greenhouse gas emissions in purple paddy soil.